Re: [BK SUMMARY] fix NGROUPS hard limit (resend)

Tim Hockin (thockin@sun.com)
Tue, 29 Oct 2002 15:20:15 -0800

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


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