Re: Testsuite for glibc mathematics.

[OndÅej BÃlka <neleai at seznam dot cz>]

Hi,

I am working on analyzing libc performance.  I started at string
functions and broadened my framework also to math functions. Here are
data that I measured in my system. I unify similar functions so for
example sin,cos,sincos,tan are for now labeled as sin.

http://kam.mff.cuni.cz/~ondra/benchmark_string/profile/result.html

There math functions are not called frequently on my computer so about
90% of spent time is caused by factors like loading them code memory.

Any program that frequently uses math functions could solve as
benchmark. 

My tool is available on
git clone https://github.com/neleai/benchmark_string
directory profile.

I now work on making it more user-friendly and allowing to compare
several implementations. 
A simple example that I just pushed is to test how is sin faster than
sinl on same output, that currently are displayed as sin2/sin3

On Mon, Nov 26, 2012 at 09:48:45AM -0600, Ryan S. Arnold wrote:
> Hi, Huan Luo,
> 
> libc-help@sourceware.org is probably the correct place for this question.
> 
> None-the-less, run "make check" after doing your build and it will run
> the integrated math/ portion of the glibc test-suite.  This is a
> "correctness" test-suite.
> 
> As far as a performance test-suite, we don't yet have anything like
> that codified.  In general, the contributors that are interested in
> the performance of portions of glibc tend to target them individually
> as they show up hot in workloads.  There has been a lot of work lately
> in the math functions in order to make them full featured with regard
> to precision and rounding.  This may have regressed performance.
> 
> Here is an example of how Adhemerval evaluated (and improved) the
> performance of __ieee754_hypot for the Power Architecture:
> 
> http://www.ibm.com/developerworks/opensource/library/l-evaluatelinuxonpower/index.html
> 
> In general, performance improvement patches are accompanied by a
> baseline analysis as well as a discussion of the preconditions and
> assumptions that influenced the patches/changes.
> 
> Regards,
> Ryan S. Arnold
> 
> On Mon, Nov 26, 2012 at 9:27 AM, Huan Luo <luo_huan_na@126.com> wrote:
> > Hi,
> >   Lately we've been studying the mathematics part in Glibc.
> > And we made a few changes to some of the functions.
> > The problem is we need a testsuite to tell us how these
> > functions' performance is affected.
> >   Can anybody introduce us a testsuite or tell us how
> > people usually test their mathematical functions?
> > Thanks very much.
> >
> >
> >
> >
> > --
> > Best wishes.
> >
> > Huan Luo

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SCSI Chain overterminated