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From: Tim Hockin <thockin@sun.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@transmeta.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [BK SUMMARY] fix NGROUPS hard limit (resend)
Date: Tue, 29 Oct 2002 15:20:15 -0800	[thread overview]
Message-ID: <3DBF17AF.8080205@sun.com> (raw)
In-Reply-To: 1035930763.1332.25.camel@irongate.swansea.linux.org.uk

Alan Cox wrote:
> On Tue, 2002-10-29 at 19:32, Timothy Hockin wrote:
> 
>>Linus,
>>
>>This patchset removes the hard NGROUPS limit.  It has been in use in a similar
>>form (but with a sysctl-set limit) on our systems for some time.
>>
>>I have a separate patch to convert XFS to the generic qsort(), which I will
>>bounce to SGI if/when this gets pulled.
> 
> 
> What is the worst case stack usage of your qsort ?

Unfortunately, I haven't done an analysis of this algorithm, but quick 
empirical tests for random, reversed, and sorted data show stack usage 
to be about 50% less than glibc's qsort() for large data sets.  We were 
using the qsort() as exists in XFS, but when discussing with Cristoph, 
he asked that we use this qsort() implementation instead.  It seems to 
perform markedly better for large sets, too.




-- 
Tim Hockin
Systems Software Engineer
Sun Microsystems, Linux Kernel Engineering
thockin@sun.com


  reply	other threads:[~2002-10-29 23:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-29 19:32 [BK SUMMARY] fix NGROUPS hard limit (resend) Timothy Hockin
2002-10-29 22:32 ` Alan Cox
2002-10-29 23:20   ` Tim Hockin [this message]
  -- strict thread matches above, loose matches on Subject: below --
2002-10-22  0:36 Timothy Hockin

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