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Re: [libc-alpha] linuxthreads bug in 2.2.4 under ppc linux


On Sunday 09 December 2001 01:59, Kevin B. Hendricks wrote:
> Hi Franz,
>
> Okay, I am down to just rebuilding libpthread.so.
>
> If I compile linuxthreads with -O1 or -O2 I can not make it fail.
>
> If I compile linuxthreads with -O3 it fails in exactly the place I
> described earlier.
>
> So the question is:
>
> Is this a ppc linux specific gcc compiler issue at -O3
> with something being rescheduled that should not be?
>
> or
>
> Is the bug in glibc-2.2.4, and the change in optimization just changes the
> timing to avoid or create the problem?
>
> I am going to diff the objdump from lipthread.so with -O2 and -O3 in
> pthread_alt_lock and pthread_alt_unlock to see is anything jumps out at me.
>
> I will let you know what if anything I find.
>
> It is nice to know that just lowering the optimization level to -O2 from
> -O3 for just linuxthreads seems to workaround the issue.

Yeah, that's quite nice. I'm happy to switch back glibc to -O2 compilation 
(-O3 isn't a big win anyway in glibc), unless you can show there is an 
underlying problem in glibc's thread code.

Franz.


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