Re: [uml-devel] Re: Stop at startup on 2.6 NPTL hosts

From: "Sven Köhler" <skoehler@upb.de>
To: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	stian@nixia.no, Blaisorblade <blaisorblade_spam@yahoo.it>,
	User-mode Linux Kernel Development
	<user-mode-linux-devel@lists.sourceforge.net>,
	Jeff Dike <jdike@addtoit.com>, Roland Kaeser <roli8200@yahoo.de>,
	Nuno Silva <nuno.silva@vgertech.com>,
	Antoine Martin <antoine@nagafix.co.uk>,
	Dennis Muhlestein <devel@muhlesteins.com>
Subject: Re: [uml-devel] Re: Stop at startup on 2.6 NPTL hosts
Date: Wed, 10 Nov 2004 15:44:21 +0100	[thread overview]
Message-ID: <41922945.2090805@upb.de> (raw)
In-Reply-To: <41920646.3090802@fujitsu-siemens.com>

>> If you want to be 100% sure you use a syscall, why not call the syscall
>> directly?
> 
> OK. It's an API call. But what's this API call defined to return? Isn't 
> it the
> pid of the process calling? If it is, the behavior of the lib is a bug. 
> If it
> isn't, the descriptions are wrong. Do you agree?

This glibc-Bug has been discussed on the LKML already. Linus was 
somewhat angry about it, since glibc should not cache. He said that this 
caching-stuff may be, because somewhat wanted to tune glibc for some 
synthetic benchmark that uses getpid() as a speed measurement. He also 
recommed to get rid of that cache - at least as far as i read the 
discussion.

So the conclusion is: override getpid() with something that does not 
cache anything since there are buggy glibc's out there, or use our own 
cache for the PID if syscalls cause to much overhead.

Thx
  Sven

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