Re: Problem with locks

2007/8/12, Gregory Stark <stark(at)enterprisedb(dot)com>:
> > "Gregory Stark" <stark(at)enterprisedb(dot)com> writes:
> >
> >> "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
> >>
> >>> Gregory Stark <stark(at)enterprisedb(dot)com> writes:
> >>>> We're seeing a problem where occasionally a process appears to be granted a
> >>>> lock but miss its semaphore signal.
> >>>
> >>> Kernel bug maybe? What's the platform?
>
> I've written a synthetic test program to check for lost semaphore wakeups. I
> can't seem to produce any on my machine but haven't had a chance to run it yet
> on the benchmark machine that's been showing the problem.
>
> If I can't produce any lost wakeups with a program like this it looks more
> like it might be a Postgres or GCC bug than a Linux bug.
>
> It would be helpful if people could run this on various architectures and
> various versions of Linux (or other OSes). I've been running it with 40
> processes for an hour, but even shorter runs would be useful. It will drive
> the load on your machine through the roof but doesn't cause any i/o.
>
> $ gcc -Wall ipctest.c -lrt
> $ ./a.out 40 3600
>
>
> --
> Gregory Stark
> EnterpriseDB http://www.enterprisedb.com
>
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Hello
[pavel(at)localhost ~]$ cat /proc/sys/kernel/osrelease
2.6.22.1-41.fc7

[pavel(at)localhost tmp]$ ./a.out 40 3600
running with 40 processes for 3600s
[pavel(at)localhost tmp]$

without any problem

Regards
Pavel Stehule