From: Paul Zimmermann <Paul.Zimmermann@inria.fr>
To: Shen-Ta Hsieh <ibmibmibm.tw@gmail.com>
Cc: libc-alpha@sourceware.org, ibmibmibm.tw@gmail.com
Subject: Re: [PATCH v6 2/3] x86_64: roundeven with sse4.1 support
Date: Sat, 22 May 2021 06:52:17 +0200 [thread overview]
Message-ID: <mwbl93mku6.fsf@tomate.loria.fr> (raw)
In-Reply-To: <20210522002227.2234377-2-ibmibmibm.tw@gmail.com> (message from Shen-Ta Hsieh via Libc-alpha on Sat, 22 May 2021 08:22:26 +0800)
Dear Shen-Ta,
> Here is a benchmark result on my AMD Ryzen 9 3900X system:
>
> * benchmark result before this commit
> | | roundeven | roundevenf |
> |------------|--------------|--------------|
> | duration | 3.77659e+09 | 3.77504e+09 |
> | iterations | 3.97043e+08 | 4.36752e+08 |
> | max | 83.714 | 58.861 |
> | min | 7.144 | 6.27 |
> | mean | 9.51179 | 8.64345 |
>
> * benchmark result after this commit
> | | roundeven | roundevenf |
> |------------|--------------|--------------|
> | duration | 3.76913e+09 | 3.76923e+09 |
> | iterations | 5.55921e+08 | 5.64822e+08 |
> | max | 211.698 | 439.09 |
> | min | 6.498 | 6.422 |
> | mean | 6.77998 | 6.6733 |
I wonder why the max times have increased by a factor 2.5 and 7.5.
In my experiments I noticed that the "mean" time was quite stable,
while the "max" time could vary a lot between different runs. Thus
I usually run 5 times "make bench" and keep the smallest times:
$ ./testrun.sh benchtests/bench-roundeven
You can also try make USE_RDTSCP=1 bench (cf benchtests/README).
And it would be nice to have figures on another hardware (for example Intel).
Best regards,
Paul Zimmermann
next prev parent reply other threads:[~2021-05-22 4:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-22 0:22 [PATCH v6 1/3] math: redirect roundeven function Shen-Ta Hsieh
2021-05-22 0:22 ` [PATCH v6 2/3] x86_64: roundeven with sse4.1 support Shen-Ta Hsieh
2021-05-22 4:52 ` Paul Zimmermann [this message]
2021-05-23 0:41 ` 謝昇達(Shen-Ta Hsieh)
2021-05-23 16:14 ` Paul Zimmermann
2021-05-23 17:10 ` H.J. Lu
2021-05-23 17:12 ` Noah Goldstein
2021-05-22 0:22 ` [PATCH v6 3/3] Use GCC builtins for roundeven functions if desired Shen-Ta Hsieh
2021-05-23 19:03 ` H.J. Lu
2021-05-24 1:22 ` 謝昇達(Shen-Ta Hsieh)
2021-05-23 18:54 ` [PATCH v6 1/3] math: redirect roundeven function H.J. Lu
2021-05-24 1:39 ` 謝昇達(Shen-Ta Hsieh)
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