Re: [Wrapper-user] ServiceWrapper starts to hang in wrapperSleep after some seconds

[Christian M. <chr...@ta...>]

Christopher & Johannes,

nanosleep is kind of very low-level system function, for which I can't
see any problems like this to be common.

There are some hooks in your mail I'd like to get closer, you said you
are running a 2CPU instance and on vmware. So i'm wondering whether
sth. with this configuration is not working as expected.

could you please run "cat /proc/<pid>/status" on the machine where
<pid> is the and send us also the output from there?
Furthermore, is NTP activated on the host?

I did some tests on our virtual machines but were not able to
reproduce the behavior you described yet...

Cheers,
Christian



On Wed, Nov 24, 2010 at 5:26 PM, Leif Mortenson
<lei...@ta...> wrote:
> Christopher & Johannes,
> Thank you for the detailed report.  This is not a problem which I am
> aware of to date.  We set up a 2 CPU VM today with cent OS and are
> running some tests locally.  So far we have not been able to reproduce
> the problem.
>
> >From what you said, it sounds like this problem only happens on
> shutdown, and can be reproduced easily?
>
> Could you please try and reproduce this with the following settings
> included in the wrapper.conf and then send me the resulting
> wrapper.log file directly?  It would be a bit large for the list.
> wrapper.debug=true
> wrapper.state_output=TRUE
>
> It sounds like the nanosleep implementation is getting stuck for some
> reason.  It is interesting that an interrupt caused by a signal is
> waking it up. We do not currently have a way to change to usleep
> without recompiling.
>
> Cheers,
> Leif
>
>
> On Tue, Nov 23, 2010 at 7:31 PM, Christopher Taylor <ct...@co...> wrote:
>> Hi all,
>>
>>
>>
>> I’m forwarding this on behalf of Johannes, he seems to be having problems
>> with his list subscription. I apologize if this is a double post, I forgot
>> to add the subject on the first mail.
>>
>>
>>
>> --- snip ---
>>
>>
>>
>> I am using ServiceWrapper (stable version 3.5.6) under 32bit CentOS 5 in a
>> VM with 2 CPUs.
>>
>>
>>
>> Whenever I stopped a Java program with the wrapper (different
>> configurations), the wrapper stopped pinging the JVM after some seconds
>> (which eventually leads to the JVM ending itself because it does not receive
>> ping packages from the wrapper any more).
>>
>>
>>
>> The last system call that never returns according to strace is always
>> nanosleep:
>>
>>
>>
>> gettimeofday({1290172014, 465559}, NULL) = 0
>>
>> read(5, 0x8895070, 1024)                = -1 EAGAIN (Resource temporarily
>> unavailable)
>>
>> gettimeofday({1290172014, 465610}, NULL) = 0
>>
>> recv(7, 0xbffa98cb, 1, 0)               = -1 EAGAIN (Resource temporarily
>> unavailable)
>>
>> waitpid(13065, 0xbffa98a8, WNOHANG|WSTOPPED) = 0
>>
>> nanosleep({0, 100000000}, NULL)         = 0
>>
>> gettimeofday({1290172014, 566505}, NULL) = 0
>>
>> read(5, 0x8895070, 1024)                = -1 EAGAIN (Resource temporarily
>> unavailable)
>>
>> gettimeofday({1290172014, 566552}, NULL) = 0
>>
>> recv(7, 0xbffa98cb, 1, 0)               = -1 EAGAIN (Resource temporarily
>> unavailable)
>>
>> waitpid(13065, 0xbffa98a8, WNOHANG|WSTOPPED) = 0
>>
>> nanosleep({0, 100000000},
>>
>>
>>
>> If I call pstack on the wrapper, you can see that two threads currently hang
>> in the nanosleep method:
>>
>>
>>
>> Thread 2 (Thread -1210287216 (LWP 13115)):
>>
>> #0  0x00994410 in __kernel_vsyscall ()
>>
>> #1  0x00d22506 in __nanosleep_nocancel () from /lib/libpthread.so.0
>>
>> #2  0x0805b0d0 in wrapperSleep ()
>>
>> #3  0x0805b420 in timerRunner ()
>>
>> #4  0x00d1b2db in start_thread () from /lib/libpthread.so.0
>>
>> #5  0x00c7512e in clone () from /lib/libc.so.6
>>
>> Thread 1 (Thread -1208169792 (LWP 13114)):
>>
>> #0  0x00994410 in __kernel_vsyscall ()
>>
>> #1  0x00d22506 in __nanosleep_nocancel () from /lib/libpthread.so.0
>>
>> #2  0x0805b0d0 in wrapperSleep ()
>>
>> #3  0x08059f6c in wrapperEventLoop ()
>>
>> #4  0x08056628 in wrapperRunConsole ()
>>
>> #5  0x0805cce3 in main ()
>>
>> #0  0x00994410 in __kernel_vsyscall ()
>>
>>
>>
>> If I send a signal to the wrapper, it reacts again, but before, it hangs
>> forever in the nanosleep method.
>>
>> Is this a known problem of ServiceWrapper  running with multiple CPUs?
>>
>> Do I have to recompile with usleep support instead or is there an option to
>> always use usleep?
>>
>>
>>
>> Best,
>>
>>   --Christopher (on behalf of Johannes)
>
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