<div dir="ltr">Did you try setting the concurrency level much higher than 8 like I suggested earlier? You are probably having multiple connections assigned to the same IO threads.<input name="virtru-metadata" type="hidden" value="{&quot;email-policy&quot;:{&quot;state&quot;:&quot;closed&quot;,&quot;expirationUnit&quot;:&quot;days&quot;,&quot;disableCopyPaste&quot;:false,&quot;disablePrint&quot;:false,&quot;disableForwarding&quot;:false,&quot;expires&quot;:false,&quot;isManaged&quot;:false},&quot;attachments&quot;:{},&quot;compose-window&quot;:{&quot;secure&quot;:false}}"><div class="gmail_extra"><br><div class="gmail_quote" style="">On Wed, Jul 25, 2018 at 12:26 PM, R. Matt Barnett <span dir="ltr">&lt;<a href="mailto:barnett@rice.edu" target="_blank">barnett@rice.edu</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Corrected test to resolve test/set race.<br>
<br>
<br>
<a href="https://gist.github.com/rmbarnett-rice/1179c4ad1d3344bb247c8b8daed3e4fa" rel="noreferrer" target="_blank">https://gist.github.com/<wbr>rmbarnett-rice/<wbr>1179c4ad1d3344bb247c8b8daed3e4<wbr>fa</a><br>
<br>
<br>
I&#39;ve also discovered this morning that I *can* see 1-8 printed on Red <br>
Hat when I generate load using ab from Windows, but only 1-4 when <br>
running ab on Red Hat (both locally and from a remote server).  I&#39;m <br>
wondering if perhaps there is some sort of connection reuse shenanigans <br>
going on.  My assumption of the use of the -c 8 parameter was &quot;make 8 <br>
sockets&quot; but maybe not.  I&#39;ll dig in and report back.<br>
<span class="HOEnZb"><font color="#888888"><br>
<br>
-- Matt<br>
</font></span><div class="HOEnZb"><div class="h5"><br>
<br>
On 7/24/2018 6:56 PM, R. Matt Barnett wrote:<br>
&gt; Hello,<br>
&gt;<br>
&gt; I&#39;m experiencing an Undertow performance issue I fail to understand.  I<br>
&gt; am able to reproduce the issue with the code linked bellow. The problem<br>
&gt; is that on Red Hat (and not Windows) I&#39;m unable to concurrently process<br>
&gt; more than 4 overlapping requests even with 8 configured IO Threads.<br>
&gt; For example, if I run the following program (1 file, 55 lines):<br>
&gt;<br>
&gt; <a href="https://gist.github.com/rmbarnett-rice/668db6b4e9f8f8da7093a3659b6ae2b5" rel="noreferrer" target="_blank">https://gist.github.com/<wbr>rmbarnett-rice/<wbr>668db6b4e9f8f8da7093a3659b6ae2<wbr>b5</a><br>
&gt;<br>
&gt; ... on Red Hat and then send requests to the server using Apache<br>
&gt; Benchmark...<br>
&gt;<br>
&gt;       &gt; ab -n 1000 -c 8 localhost:8080/<br>
&gt;<br>
&gt; I see the following output from the Undertow process:<br>
&gt;<br>
&gt;       Server started on port 8080<br>
&gt;<br>
&gt;       1<br>
&gt;       2<br>
&gt;       3<br>
&gt;       4<br>
&gt;<br>
&gt; I believe this demonstrates that only 4 requests are ever processed in<br>
&gt; parallel.  I would expect 8.  In fact, when I run the same experiment on<br>
&gt; Windows I see the expected output of<br>
&gt;<br>
&gt;       Server started on port 8080<br>
&gt;       1<br>
&gt;       2<br>
&gt;       3<br>
&gt;       4<br>
&gt;       5<br>
&gt;       6<br>
&gt;       7<br>
&gt;       8<br>
&gt;<br>
&gt; Any thoughts as to what might explain this behavior?<br>
&gt;<br>
&gt; Best,<br>
&gt;<br>
&gt; Matt<br>
&gt;<br>
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