Re: Process with many NPTL threads terminates slowly on core dump signal

["Michael Kerrisk" <mtk-lkml@gmx.net>]

> Von: Oleg Nesterov <oleg@tv-sign.ru>
> Datum: Wed, 12 Oct 2005 21:33:46 +0400
> 
> Michael Kerrisk wrote:
> >
> > Following up (belatedly) from my earlier message, I took Daniel 
> > Jacobowitz's suggestion to investigate the result from booting 
> > with "profile=2".  When running my program (shwon below) on 
> > 2.6.14-rc4 to create 100 threads, and sending a core dump signal, 
> > the program takes 90 seconds to terminate, and readprofile shows 
> > the following:
> 
> I think the coredumping code in __group_complete_signal() is bogus
> and what happens is:

[...]

> TIF_SIGPENDING is not cleared, so get_signal_to_deliver() will be
> called again on return to userspace. When all threads will eat their
> ->time_slice, P will return from yield() and kill all threads.

Thanks for investiagting this further.

> Could you try this patch (added to mm tree):
> 	http://marc.theaimsgroup.com/?l=linux-kernel&m=112887453531139
> ? It does not solve the whole problem, but may help.
>
> Please report the result, if possible.

Thanks.  I've applied it to 2.6.14-rc4: this patch does fix the 
specific behaviour that my program demonstrates.  

What remains to be solved?

Cheers,

Michael

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