[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Michal Babacek (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Michal Babacek updated MODCLUSTER-372:
--------------------------------------
Attachment: callgrind.zip
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, callgrind.zip, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Michal Babacek (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Michal Babacek commented on MODCLUSTER-372:
-------------------------------------------
I've identified these bottle necks:
Three the most expensive functions and their callers:
# Function {{ap_slotmem_mem}} from mod_slotmem/sharedmem_util.c called by:
* {{get_context}} from mod_manager/context.c
* {{get_node}} from mod_manager/node.c
* {{loc_read_node}} from mod_manager/mod_manager.c
* {{find_node_context_host}} from mod_proxy_cluster/mod_proxy_cluster.c
* {{loc_read_context}} mod_manager/context.c
* {{read_context_table}} mod_proxy_cluster/mod_proxy_cluster.c
* {{manager_info}} from mod_manager/mod_manager.c
# Function {{ap_slotmem_do}} from mod_slotmem/sharedmem_util.c called mostly by
* httpd_request and httpd_core functions from httpd sources.
# Function {{find_node_context_host}} from mod_proxy_cluster/mod_proxy_cluster.c called by
* httpd sources, mostly on request_process and request_connection.
So, IMHO, {{find_node_context_host}} is indeed the trouble :)
Attaching the profiling valgrind logs [^callgrind.zip], created as:
{noformat}
valgrind --tool=callgrind --dump-instr=yes --simulate-cache=yes --collect-jumps=yes --compress-strings=no --compress-pos=no --collect-systime=yes ./httpd -f /tmp/hudson/httpd/conf/httpd.conf -E /tmp/hudson/httpd/logs/httpd.log
{noformat}
with this debug setting:
{code}
<IfModule worker.c>
ThreadLimit 50
StartServers 1
ServerLimit 1
MinSpareThreads 50
MaxSpareThreads 50
MaxClients 50
ThreadsPerChild 50
MaxRequestsPerChild 0
</IfModule>
{code}
and 4 worker nodes, 65 contexts each, and several dozens of concurrent client sessions.
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Jean-Frederic Clere (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Jean-Frederic Clere commented on MODCLUSTER-372:
------------------------------------------------
Looking in mod_proxy_cluster.c find_node_context_host() I have spotted something very bad:
+++
/* keep only the contexts corresponding to our balancer */
if (balancer != NULL) {
nodeinfo_t *node;
if (node_storage->read_node(context->node, &node) != APR_SUCCESS)
continue;
+++
We are reading the shared memory for each context that is _very_ bad.
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Michal Babacek (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Michal Babacek commented on MODCLUSTER-372:
-------------------------------------------
I can see I forgot to add {{ServerLimit 40}}, but it would only allow for MaxClients to be higher than 1920, and actually shouldn't have any bearing on the case of mod_cluster and registered contexts.
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Radoslav Husar (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Radoslav Husar updated MODCLUSTER-372:
--------------------------------------
Tester: Michal Babacek
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by RH Bugzilla Integration (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
RH Bugzilla Integration updated MODCLUSTER-372:
-----------------------------------------------
Bugzilla Update: Perform
Bugzilla References: https://bugzilla.redhat.com/show_bug.cgi?id=1030965
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months
[JBoss JIRA] (MODCLUSTER-372) Number of registered contexts negatively affects mod_cluster performance
by Michal Babacek (JIRA)
[ https://issues.jboss.org/browse/MODCLUSTER-372?page=com.atlassian.jira.pl... ]
Michal Babacek updated MODCLUSTER-372:
--------------------------------------
Description:
There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
[^httpd.conf] attached, stay tuned for some profiler outputs...
h3. 9 workers, 31 contexts, round robin
!9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8843|147.4|15|60|0|8843|100%|
|9|250|250|14422|240.3|37|215|0|14422|100%|
|9|350|350|17551|292.5|196|443|0|17551|100%|
|9|450|450|21303|355.0|269|603|0|21303|100%|
|9|550|550|24818|413.6|325|686|0|24818|100%|
|9|650|650|26804|446.7|469|800|0|26804|100%|
|9|750|750|29930|498.8|507|985|0|29930|100%|
|9|850|850|30665|511.0|665|1185|0|30665|100%|
|9|950|950|34421|573.6|647|1316|0|34421|100%|
|9|1050|1050|35067|584.4|800|1487|0|35067|100%|
|9|1150|1150|36024|600.4|925|1612|0|36024|100%|
|9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
|9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
|9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
|9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
|9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
|9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
|9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
|9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
|9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
|9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
|9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
h3. 9 workers, 31 contexts, accessing only one of them
!9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8954|149.2|4|42|0|8954|100%|
|9|250|250|14897|248.3|7|33|0|14897|100%|
|9|350|350|20784|346.4|8|68|0|20784|100%|
|9|450|450|26748|445.8|8|69|0|26748|100%|
|9|550|550|32553|542.5|11|92|0|32553|100%|
|9|650|650|38558|642.6|10|60|0|38558|100%|
|9|750|750|43571|726.1|29|329|0|43571|100%|
|9|850|850|46133|768.8|99|494|0|46133|100%|
|9|950|950|50854|847.5|120|501|0|50854|100%|
|9|1050|1050|54451|907.4|154|584|0|54451|100%|
|9|1150|1150|59961|999.3|138|674|0|59961|100%|
|9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
|9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
|9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
|9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
|9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
|9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
|9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
|9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
|9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
|9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
|9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
h3. 9 workers, 1 context
!9-workers-1-context-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8965|149.4|2|12|0|8965|100%|
|9|250|250|14965|249.4|2|22|0|14965|100%|
|9|350|350|20950|349.1|2|23|0|20950|100%|
|9|450|450|26941|449.0|2|26|0|26941|100%|
|9|550|550|32937|548.9|1|26|0|32937|100%|
|9|650|650|38900|648.3|1|19|0|38900|100%|
|9|750|750|44918|748.6|1|11|0|44918|100%|
|9|850|850|50902|848.3|2|22|0|50902|100%|
|9|950|950|56878|947.9|1|14|0|56878|100%|
|9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
|9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
|9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
|9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
|9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
|9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
|9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
|9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
|9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
|9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
|9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
|9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
|9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
h3. 4 workers, 61 contexts, accessing only one of them
!4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|4|500|500|29796|496.6|6|52|0|29796|100%|
|4|650|650|38706|645.0|7|149|0|38706|100%|
|4|800|800|47585|793.0|8|129|0|47585|100%|
|4|950|950|54467|907.7|43|377|0|54467|100%|
|4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
|4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
|4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
|4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
|4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
|4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
|4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
|4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
h3. 4 workers, 1 context
!4-workers-1-context-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|4|500|500|29922|498.7|2|39|0|29922|100%|
|4|650|650|38923|648.7|1|39|0|38923|100%|
|4|800|800|47916|798.5|1|17|0|47916|100%|
|4|950|950|56896|948.2|1|17|0|56896|100%|
|4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
|4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
|4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
|4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
|4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
|4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
|4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
|4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
was:
There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
Stay tuned for some profiler outputs...
The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
h3. 9 workers, 31 contexts, round robin
!9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8843|147.4|15|60|0|8843|100%|
|9|250|250|14422|240.3|37|215|0|14422|100%|
|9|350|350|17551|292.5|196|443|0|17551|100%|
|9|450|450|21303|355.0|269|603|0|21303|100%|
|9|550|550|24818|413.6|325|686|0|24818|100%|
|9|650|650|26804|446.7|469|800|0|26804|100%|
|9|750|750|29930|498.8|507|985|0|29930|100%|
|9|850|850|30665|511.0|665|1185|0|30665|100%|
|9|950|950|34421|573.6|647|1316|0|34421|100%|
|9|1050|1050|35067|584.4|800|1487|0|35067|100%|
|9|1150|1150|36024|600.4|925|1612|0|36024|100%|
|9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
|9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
|9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
|9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
|9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
|9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
|9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
|9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
|9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
|9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
|9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
h3. 9 workers, 31 contexts, accessing only one of them
!9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8954|149.2|4|42|0|8954|100%|
|9|250|250|14897|248.3|7|33|0|14897|100%|
|9|350|350|20784|346.4|8|68|0|20784|100%|
|9|450|450|26748|445.8|8|69|0|26748|100%|
|9|550|550|32553|542.5|11|92|0|32553|100%|
|9|650|650|38558|642.6|10|60|0|38558|100%|
|9|750|750|43571|726.1|29|329|0|43571|100%|
|9|850|850|46133|768.8|99|494|0|46133|100%|
|9|950|950|50854|847.5|120|501|0|50854|100%|
|9|1050|1050|54451|907.4|154|584|0|54451|100%|
|9|1150|1150|59961|999.3|138|674|0|59961|100%|
|9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
|9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
|9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
|9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
|9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
|9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
|9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
|9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
|9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
|9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
|9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
h3. 9 workers, 1 context
!9-workers-1-context-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|9|150|150|8965|149.4|2|12|0|8965|100%|
|9|250|250|14965|249.4|2|22|0|14965|100%|
|9|350|350|20950|349.1|2|23|0|20950|100%|
|9|450|450|26941|449.0|2|26|0|26941|100%|
|9|550|550|32937|548.9|1|26|0|32937|100%|
|9|650|650|38900|648.3|1|19|0|38900|100%|
|9|750|750|44918|748.6|1|11|0|44918|100%|
|9|850|850|50902|848.3|2|22|0|50902|100%|
|9|950|950|56878|947.9|1|14|0|56878|100%|
|9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
|9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
|9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
|9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
|9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
|9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
|9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
|9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
|9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
|9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
|9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
|9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
|9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
h3. 4 workers, 61 contexts, accessing only one of them
!4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|4|500|500|29796|496.6|6|52|0|29796|100%|
|4|650|650|38706|645.0|7|149|0|38706|100%|
|4|800|800|47585|793.0|8|129|0|47585|100%|
|4|950|950|54467|907.7|43|377|0|54467|100%|
|4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
|4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
|4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
|4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
|4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
|4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
|4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
|4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
h3. 4 workers, 1 context
!4-workers-1-context-balancer-cpu.png|thumbnail!
||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
|4|500|500|29922|498.7|2|39|0|29922|100%|
|4|650|650|38923|648.7|1|39|0|38923|100%|
|4|800|800|47916|798.5|1|17|0|47916|100%|
|4|950|950|56896|948.2|1|17|0|56896|100%|
|4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
|4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
|4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
|4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
|4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
|4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
|4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
|4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
> Number of registered contexts negatively affects mod_cluster performance
> ------------------------------------------------------------------------
>
> Key: MODCLUSTER-372
> URL: https://issues.jboss.org/browse/MODCLUSTER-372
> Project: mod_cluster
> Issue Type: Bug
> Affects Versions: 1.2.4.Final, 1.2.6.Final
> Environment: RHEL6, other platforms are to be confirmed.
> Reporter: Michal Babacek
> Assignee: Michal Babacek
> Labels: mod_cluster, performace
> Fix For: 1.2.7.Final, 1.3.0.Alpha2
>
> Attachments: 4-workers-1-context-balancer-cpu.png, 4-workers-61-context-accessing-1-balancer-cpu.png, 9-workers-1-context-balancer-cpu.png, 9-workers-31-context-accessing-1-balancer-cpu.png, 9-workers-31-context-round-robin-balancer-cpu.png, httpd.conf
>
>
> There is a performance concern regarding CPU usage on the Apache HTTP Server with mod_cluster set up as a load balancer. Perf tests revealed that the major variable affecting the CPU usage is the overall number of registered contexts. It's noteworthy that these contexts actually don't need to be accessed at all, it's enough that they are present.
> The first test [9 workers, 31 contexts, round robin|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,...] depicts a behavior where all contexts are being accessed in a round robin fashion. Note the CPU usage. If we compare it to the [9 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,1context] test, it becomes apparent that there is something wrong with the CPU usage. As it is clear from the [9 workers, 31 contexts, access 1|https://issues.jboss.org/browse/MODCLUSTER-372#9workers,31contexts,acce...] test, accessing only one of these contexts doesn't help much.
> The last two tests, [4 workers, 61 contexts, accessing 1|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,61contexts,acce...] and [4 workers, 1 context|https://issues.jboss.org/browse/MODCLUSTER-372#4workers,1context] confirm the results, environment differs only in number of nodes and number of contexts.
> [^httpd.conf] attached, stay tuned for some profiler outputs...
> h3. 9 workers, 31 contexts, round robin
> !9-workers-31-context-round-robin-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8843|147.4|15|60|0|8843|100%|
> |9|250|250|14422|240.3|37|215|0|14422|100%|
> |9|350|350|17551|292.5|196|443|0|17551|100%|
> |9|450|450|21303|355.0|269|603|0|21303|100%|
> |9|550|550|24818|413.6|325|686|0|24818|100%|
> |9|650|650|26804|446.7|469|800|0|26804|100%|
> |9|750|750|29930|498.8|507|985|0|29930|100%|
> |9|850|850|30665|511.0|665|1185|0|30665|100%|
> |9|950|950|34421|573.6|647|1316|0|34421|100%|
> |9|1050|1050|35067|584.4|800|1487|0|35067|100%|
> |9|1150|1150|36024|600.4|925|1612|0|36024|100%|
> |9|1250|1250|36635|610.5|1030|1815|0|36635|100%|
> |9|1350|1350|38395|639.9|1096|1942|0|38395|100%|
> |9|1450|1450|39713|661.8|1170|2466|0|39713|100%|
> |9|1550|1550|39455|657.5|1392|2340|0|39455|100%|
> |9|1650|1650|39849|664.1|1465|4240|0|39849|100%|
> |9|1750|1750|42435|707.2|1454|6511|0|42435|100%|
> |9|1850|1850|44714|745.2|1498|4866|0|44714|100%|
> |9|1950|1911|46072|767.8|1554|43016|0|46072|100%|
> |9|2050|1911|44496|741.5|1617|4953|39|44457|99%|
> |9|2150|1911|43715|728.5|1632|5348|125|43590|99%|
> |9|2250|1911|41112|685.1|1764|9800|155|40957|99%|
> h3. 9 workers, 31 contexts, accessing only one of them
> !9-workers-31-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8954|149.2|4|42|0|8954|100%|
> |9|250|250|14897|248.3|7|33|0|14897|100%|
> |9|350|350|20784|346.4|8|68|0|20784|100%|
> |9|450|450|26748|445.8|8|69|0|26748|100%|
> |9|550|550|32553|542.5|11|92|0|32553|100%|
> |9|650|650|38558|642.6|10|60|0|38558|100%|
> |9|750|750|43571|726.1|29|329|0|43571|100%|
> |9|850|850|46133|768.8|99|494|0|46133|100%|
> |9|950|950|50854|847.5|120|501|0|50854|100%|
> |9|1050|1050|54451|907.4|154|584|0|54451|100%|
> |9|1150|1150|59961|999.3|138|674|0|59961|100%|
> |9|1250|1250|62567|1,042.6|198|675|0|62567|100%|
> |9|1350|1350|61939|1,032.2|301|799|0|61939|100%|
> |9|1450|1450|67920|1,131.9|276|844|0|67920|100%|
> |9|1550|1550|73151|1,219.1|261|861|0|73151|100%|
> |9|1650|1650|73937|1,232.2|332|955|0|73937|100%|
> |9|1750|1750|73516|1,225.2|423|1046|0|73516|100%|
> |9|1850|1850|72556|1,209.1|515|1264|0|72556|100%|
> |9|1950|1911|78613|1,310.1|454|50273|0|78613|100%|
> |9|2050|1911|80141|1,335.6|431|1225|39|80102|99%|
> |9|2150|1911|76979|1,282.9|490|1338|127|76852|99%|
> |9|2250|1911|78048|1,300.7|464|1305|136|77912|99%|
> h3. 9 workers, 1 context
> !9-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |9|150|150|8965|149.4|2|12|0|8965|100%|
> |9|250|250|14965|249.4|2|22|0|14965|100%|
> |9|350|350|20950|349.1|2|23|0|20950|100%|
> |9|450|450|26941|449.0|2|26|0|26941|100%|
> |9|550|550|32937|548.9|1|26|0|32937|100%|
> |9|650|650|38900|648.3|1|19|0|38900|100%|
> |9|750|750|44918|748.6|1|11|0|44918|100%|
> |9|850|850|50902|848.3|2|22|0|50902|100%|
> |9|950|950|56878|947.9|1|14|0|56878|100%|
> |9|1050|1050|62874|1,047.8|2|12|0|62874|100%|
> |9|1150|1150|68845|1,147.3|2|99|0|68845|100%|
> |9|1250|1250|74851|1,247.4|2|103|0|74851|100%|
> |9|1350|1350|80826|1,347.0|2|100|0|80826|100%|
> |9|1450|1450|86806|1,446.7|2|19|0|86806|100%|
> |9|1550|1550|92817|1,546.8|2|52|0|92817|100%|
> |9|1650|1650|98774|1,646.1|2|18|0|98774|100%|
> |9|1750|1750|104755|1,745.8|2|18|0|104755|100%|
> |9|1850|1850|110734|1,845.4|2|20|0|110734|100%|
> |9|1950|1910|113419|1,890.2|9|41855|0|113419|100%|
> |9|2050|1911|114437|1,907.1|2|77962|39|114397|99%|
> |9|2150|1911|114481|1,907.9|2|15|128|114353|99%|
> |9|2250|1911|114545|1,908.9|2|24|144|114401|99%|
> h3. 4 workers, 61 contexts, accessing only one of them
> !4-workers-61-context-accessing-1-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29796|496.6|6|52|0|29796|100%|
> |4|650|650|38706|645.0|7|149|0|38706|100%|
> |4|800|800|47585|793.0|8|129|0|47585|100%|
> |4|950|950|54467|907.7|43|377|0|54467|100%|
> |4|1100|1100|62500|1,041.6|54|396|0|62500|100%|
> |4|1250|1250|69446|1,157.3|81|512|0|69446|100%|
> |4|1400|1400|76217|1,270.2|97|517|0|76217|100%|
> |4|1550|1550|80216|1,336.8|152|810|0|80216|100%|
> |4|1700|1700|80797|1,346.5|271|864|0|80797|100%|
> |4|1850|1850|94172|1,569.3|182|822|0|94172|100%|
> |4|2000|1916|91014|1,516.8|253|48650|0|91014|100%|
> |4|2150|1916|95852|1,597.4|205|848|83|95769|99%|
> h3. 4 workers, 1 context
> !4-workers-1-context-balancer-cpu.png|thumbnail!
> ||Nodes||Sessions||Ses.Active||Samples||samples/s||mean resp. ms||max resp. ms||conn. errors||valid samples||%||
> |4|500|500|29922|498.7|2|39|0|29922|100%|
> |4|650|650|38923|648.7|1|39|0|38923|100%|
> |4|800|800|47916|798.5|1|17|0|47916|100%|
> |4|950|950|56896|948.2|1|17|0|56896|100%|
> |4|1100|1100|65889|1,098.1|1|115|0|65889|100%|
> |4|1250|1250|74874|1,247.8|1|101|0|74874|100%|
> |4|1400|1400|83818|1,396.8|1|17|0|83818|100%|
> |4|1550|1550|92830|1,547.0|1|17|0|92830|100%|
> |4|1700|1700|101805|1,696.6|1|11|0|101805|100%|
> |4|1850|1850|110785|1,846.3|1|11|0|110785|100%|
> |4|2000|1916|113747|1,895.6|10|53108|0|113747|100%|
> |4|2150|1916|114825|1,913.6|1|24|83|114742|99%|
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10 years, 5 months