Salut,
Oleksiy Stashok wrote:
> Hi John,
>
>>
>> My apologies.
>>
>>
>> No problem. What was the issue with the test? I'm still interested
>> to reproduce the issue as I suspect a JDK bug.
>>
>>
>> Ok, well I have a simple program now that demonstrates the problem. I
>> also boiled it down to be make it easier to build and run from command
>> line.
>>
>> The idea is to increase the probability of the event described in the
>> evaluation section of http://bugs.sun.com/view_bug.do?bug_id=6693490.
>>
>> proto.TReceive will use grizzly to open and close a socket at high
>> frequency. It is using a ReadFilter to read from the socket and
>> another filter to count the number of reads. After sometime, TRecieve
>> will sleep for about 5 seconds and then continue.
>>
>> proto.UDPSender simply sends a stream of packets at TReceives read socket.
>>
>> The select spin is demonstrated quickly. Start TReciver first and
>> note the cpu utilization; there are no packets arriving and the
>> utilization should be on the low side, and zero during the sleep
>> time. Then run UDPSender for some time, then kill it. There would
>> again be no packets arriving and TReceiver's cpu utilization should be
>> on the low side, and zero during the sleep time. However, if there is
>> a select spin, the cpu utilization would be higher than before
>> UDPSender was started. WIth a single thread spinning, one of the
>> cores would be 100% utilized.
>>
>> Now, how long should you run UDPSender for? On a dual core cpu on my
>> laptop, the effect is demonstrated within 30 seconds of running
>> UDPSender. The spin may to be correlated to the appearance of this
>> exception from TReceiver:
>>
>> Apr 16, 2009 1:57:50 AM com.sun.grizzly.Controller handleSelectException
>> SEVERE: Selector was unexpectedly closed.
>>
>>
>> So, here is how you can run it:
>>
>> 1) unjar the attachment and build using maven.
>> 2) get the class path using maven: mvn dependency:build-classpath
>> 3) run TReceiver using that classpath:
>> java -cp <classpath from above>:target/classes proto.TReceiver
>> 4) run UDPSender (no special classpath needed)
>> java -cp target/classes proto.UDPSender
> Just tried to reproduce this during hour, no success :(
> Can you please write more about:
>> SEVERE: Selector was unexpectedly closed.
>
> is there complete stacktrace?
> Cause I got lots of exceptions, but this one didn't see.
Are you running on linux? Just checking as you usually on OS X :-)
A+
-- Jeanfrancois
>
> Thanks.
>
> WBR,
> Alexey.
>
>>
>>
>> Regards,
>> John
>>
>>
>>
>> Thanks!
>>
>> -- Jeanfrancois
>>
>>
>> John
>>
>>
>>
>> On Tue, Apr 14, 2009 at 10:14 AM, Jeanfrancois Arcand
>> <Jeanfrancois.Arcand_at_sun.com
>> <mailto:Jeanfrancois.Arcand_at_sun.com>
>> <mailto:Jeanfrancois.Arcand_at_sun.com
>> <mailto:Jeanfrancois.Arcand_at_sun.com>>> wrote:
>>
>> Salut,
>>
>> back online
>>
>>
>> John Franey wrote:
>>
>> Jeanfrancois,
>>
>> Just a couple of clarifications:
>>
>> 1) Running from the command line needs the jar files
>> too. Sorry
>> I gave the impression that it was too easy. I think
>> its easiest
>> to run from IDE, especially since a debugger is needed.
>> I hope
>> that is ok.
>>
>>
>> OK I will try to reproduce the issue but I usually don't
>> use IDE (I
>> use vim :-)).
>>
>>
>>
>>
>> 2) Also, the BReceiver won't be idle during the rest
>> sleeps.
>> Sorry about that. Instead, once the exception occurs,
>> simply
>> kill the UDPSender process, then you will be sure the
>> BReceiver
>> is not receiving any new packets.
>>
>>
>> OK. BTW I've talked to the NIO/JDK lead and nothing about
>> spinning
>> selector has been reported on jdk 4/5/6 so we might need to
>> closely
>> look at your code.
>>
>> Thanks
>>
>> -- Jeanfrancois
>>
>>
>>
>> Regards,
>> John
>>
>>
>>
>> On Thu, Apr 9, 2009 at 2:31 PM, John Franey
>> <jjfraney_at_gmail.com <mailto:jjfraney_at_gmail.com>
>> <mailto:jjfraney_at_gmail.com <mailto:jjfraney_at_gmail.com>>
>> <mailto:jjfraney_at_gmail.com <mailto:jjfraney_at_gmail.com>
>>
>> <mailto:jjfraney_at_gmail.com
>> <mailto:jjfraney_at_gmail.com>>>> wrote:
>>
>> Jeanfrancois,
>>
>> I got lucky, here is a test case. (gmail didn't let
>> me send
>> it as
>> zip, so its a jar).
>>
>> this is a maven project, I guess you can build and run.
>>
>> There are two main classes.
>>
>> A receiver, BReceiver, and a sender, UDPSender.
>>
>> I run these from eclipse. I guess your IDE will let
>> your run
>> them
>> easily, but I guess from the command line something
>> easy like:
>> java -cp target/classes grizzlyproto/BReceiver would
>> run.
>>
>> BReciever cycles a single udp port through many
>> connections.
>> UDPSender sends datagrams to that port at high rate.
>>
>> Periodically, BReceiver pauses at a time when there
>> should be
>> no cpu
>> charges to that process. Not sure this helps, but the
>> intention was
>> that if the process is using cpu at this time, then the
>> selector is
>> spinning.
>>
>> Within a few moment, BReceiver will get an exception
>> (I do
>> not know
>> if the exception is related to the problem). Then
>> you can set
>> breakpoint on Controller.doSelect's return from
>> selectorHandler.select (at line 329) to inspect value of
>> readyKeys. Its empty.
>>
>>
>> Here are my system specificaitons (from ubuntu 8.10)
>> Linux isidore 2.6.27-11-generic #1 SMP Thu Jan 29
>> 19:28:32
>> UTC 2009
>> x86_64 GNU/Linux
>>
>>
>> I get the same behavior on both of these:
>>
>> java version "1.6.0_12"
>> Java(TM) SE Runtime Environment (build 1.6.0_12-b04)
>> Java HotSpot(TM) 64-Bit Server VM (build 11.2-b01,
>> mixed mode)
>>
>> and
>>
>> java version "1.6.0_03"
>> Java(TM) SE Runtime Environment (build 1.6.0_03-b05)
>> BEA JRockit(R) (build
>> R27.5.0-110-94909-1.6.0_03-20080204-1558-linux-x86_64,
>> compiled mode)
>>
>>
>> Regards,
>> John
>>
>>
>>
>> On Thu, Apr 9, 2009 at 2:00 PM, John Franey
>> <jjfraney_at_gmail.com <mailto:jjfraney_at_gmail.com>
>> <mailto:jjfraney_at_gmail.com <mailto:jjfraney_at_gmail.com>>
>> <mailto:jjfraney_at_gmail.com
>> <mailto:jjfraney_at_gmail.com> <mailto:jjfraney_at_gmail.com
>> <mailto:jjfraney_at_gmail.com>>>> wrote:
>>
>> Thanks.
>>
>>
>> On Thu, Apr 9, 2009 at 1:02 PM, Jeanfrancois Arcand
>> <Jeanfrancois.Arcand_at_sun.com
>> <mailto:Jeanfrancois.Arcand_at_sun.com>
>> <mailto:Jeanfrancois.Arcand_at_sun.com
>> <mailto:Jeanfrancois.Arcand_at_sun.com>>
>> <mailto:Jeanfrancois.Arcand_at_sun.com
>> <mailto:Jeanfrancois.Arcand_at_sun.com>
>> <mailto:Jeanfrancois.Arcand_at_sun.com
>> <mailto: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
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711>
>>
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711>>
>>
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711>
>>
>> <https://issues.apache.org/jira/browse/DIRMINA-678?focusedCommentId=12696711&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12696711
>> <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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