users@grizzly.java.net

Re: do select spin on linux

From: John Franey <jjfraney_at_gmail.com>
Date: Thu, 9 Apr 2009 14:00:52 -0400

Thanks.


On Thu, Apr 9, 2009 at 1:02 PM, Jeanfrancois Arcand <
Jeanfrancois.Arcand_at_sun.com> wrote:

> Salut,
>
> John Franey wrote:
>
>> Hi,
>>
>> I'm running stress tests on linux. At some point, cpu utilization goes
>> high. I've verified using the debugger that Controller.doSelect gets zero
>> keys back from handler's select.
>>
>
> Yes this is an issue I've reported awhile ago to the JDK team. This sounds
> like bugparade 6403933
>
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6403933
>
> A connection is reset causes the file descriptor to be selected with events
> POLLHUP and POLLERR but unless there is data waiting to be read then channel
> will not be selected. It's a awkward problem.
>
> This has been fixed in JDK 7 build 50 and will be included in JDK 6u16.
>
>
The last statement in the evaluation of this bug nails it, and the load
pattern described in this bug matches mine:
http://bugs.sun.com/view_bug.do?bug_id=6693490

It sounds like the same root cause?


>
>> Google search led me to this page at apache mina jira DIRMINA-678 <
>> https://issues.apache.org/jira/browse/DIRMINA-678>.
>>
>> Please see especially, this comment from Emannual Lecharmy (31/Mar/09
>> 03:23 PM) <
>> https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711
>> >.
>>
>> So, I'm looking for this 'beautiful hack' in the Controller source code
>> for 1.9.11 and am not seeing it. I think maybe I'm blind :) or the hack is
>> in grizzly 2.0? If its in 2.0, do you think I can make it fit into 1.9.11?
>> Or do you advise I try my application on 2.0 trunk?
>>
>
> I didn't put the hack there (just for Comet) as I never saw it on the
> Controller. Can you share a test case?
>

I don't have a test case and am working on one. I would be surprised if I
can get it to happen without a lot of work.

Is there a code sample from comet that has this hack in it to see if I can
make the same change for my app?


>
> Thanks
>
> -- Jeanfrancois
>
>
>
>> Thanks,
>> John
>>
>>
>>
>>
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