[infinispan-dev] Is anyone else experiencing JGRP-1675

[Radim Vansa]

On 10/16/2013 04:08 PM, Bela Ban wrote:
> (1) Taking flow control out of a config is a *bad thing* unless
>        * your message is small or
>        * you make a blocking RPC. In this case you could use NO_FC,
> bypassing flow control. Not sure if Infinispan does this
Infinispan mostly uses dispatchers with blocking RPC - there are some 
messages with ResponseMode.GET_NONE, but these are usually used only 
after some blocking communication (I think that TxNotificationCommand is 
sent this way). So, for Infinispan the FC may not be really needed.

>
> (2) Use MFC/UFC rather than FC, which is deprecated
I think that FC is misleading acronym for FlowControl - as MFC and UFC 
inherit from FlowControl, shortening it to FC is touting.

Radim

>
> On 10/11/13 3:22 PM, Erik Salter wrote:
>> Hi Radim,
>>
>> If you're using VMs, this may be of use.  I actually experienced a JGroups
>> lockup in production with FC in decrementCredits.  What happened in my case
>> is that virtualization tools had actually screwed with the system clock --
>> it was reported that JBoss took ~1 year to start.
>>
>> http://www.vmware.com/pdf/vmware_timekeeping.pdf
>>
>> The upshot is that I had to take FC out of my stack going forward.
>>
>> Erik
>>
>> -----Original Message-----
>> From: infinispan-dev-bounces at lists.jboss.org
>> [mailto:infinispan-dev-bounces at lists.jboss.org] On Behalf Of Radim Vansa
>> Sent: Friday, October 11, 2013 8:41 AM
>> To: infinispan-dev at lists.jboss.org
>> Subject: [infinispan-dev] Is anyone else experiencing JGRP-1675
>>
>> Hi,
>>
>> since Infinispan moved to JGroups 3.4, we're experiencing occassional
>> deadlocks in some tests - most of threads that send anything over JGroups
>> are waiting in JGroups' FlowControl.decrementCredits. The problem sometimes
>> goes away after several seconds, but it produces some ugly spikes in our
>> througput/response time charts. Originally this affected just some RadarGun
>> tests but this is appearing in some client-server tests as well (we've
>> recently investigated an issue where this appeared in a regular soak test).
>> I was looking into that [1] for some time but haven't really figured out the
>> cause. The workaround is to set up MFC and UFC credits high enough (I use
>> 10M) and stuff works then. I was trying to reproduce that on pure JGroups,
>> but unsuccessfully.
>> I am not asking anyone to dig into that, but I wanted to know whether QA is
>> alone experiencing that or if there are more of us.
>>
>> Radim
>>
>> [1] https://issues.jboss.org/browse/JGRP-1675
>>
>> --
>> Radim Vansa <rvansa at redhat.com>
>> JBoss DataGrid QA
>>
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-- 
Radim Vansa <rvansa at redhat.com>
JBoss DataGrid QA