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From: Steven Noonan <steven@uplinklabs.net>
To: Giuseppe Scrivano <gscrivano@gnu.org>
Cc: "Pádraig Brady" <P@draigbrady.com>,
	Bug-coreutils@gnu.org,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Git Mailing List" <git@vger.kernel.org>
Subject: Re: Linus' sha1 is much faster!
Date: Mon, 17 Aug 2009 08:44:30 -0700	[thread overview]
Message-ID: <f488382f0908170844h649126efxb27f87d7b319961b@mail.gmail.com> (raw)
In-Reply-To: <8763cmemsa.fsf@master.homenet>

On Mon, Aug 17, 2009 at 3:51 AM, Giuseppe Scrivano<gscrivano@gnu.org> wrote:
> Pádraig Brady <P@draigBrady.com> writes:
>
>>   -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
>>   -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i586
>>   -mtune=generic -fasynchronous-unwind-tables -D_GNU_SOURCE=1
>
> thanks.  I did again all tests on my machine using these same options.
> I repeated each test 6 times and I took the median without consider the
> first result.  Except the first run that it is not considered, I didn't
> report a big variance on results of the same test.
>
>
> gcc 4.3.3
>
> gnulib sha1:            real    0m2.543s
> gnulib sha1 lookup:     real    0m1.906s (-25%)
> linus's sha1:           real    0m2.468s (-3%)
> linus's sha1 no asm:    real    0m2.289s (-9%)
>
>
> gcc 4.4.1
>
> gnulib sha1:            real    0m3.386s
> gnulib sha1 lookup:     real    0m3.110s (-8%)
> linus's sha1:           real    0m1.701s (-49%)
> linus's sha1 no asm:    real    0m1.284s (-62%)
>
>
> I don't see such big differences in asm generated by gcc 4.4.1 and gcc
> 4.3.3 to explain this performance difference, what I noticed immediately
> is that in the gcc-4.4 generated asm there are more "lea" instructions
> (+30%), but I doubt this is the reason of these poor results.  Anyway, I
> haven't yet looked much in details.
>
> Cheers,
> Giuseppe

Interesting. I compared Linus' implementation to the public domain one
by Steve Reid[1], which is used in OpenLDAP and a few other projects.
Anyone with some experience testing these kinds of things in a
statistically sound manner want to try it out? In my tests, I got
this:

(average of 5 runs)
Linus' sha1: 283MB/s
Steve Reid's sha1: 305MB/s

- Steven

[1] http://gpl.nas-central.org/SYNOLOGY/x07-series/514_UNTARED/source/openldap-2.3.11/libraries/liblutil/sha1.c

  reply	other threads:[~2009-08-17 15:44 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-14 23:25 Linus' sha1 is much faster! Pádraig Brady
2009-08-15 20:02 ` Bryan Donlan
2009-08-15 20:12   ` John Tapsell
2009-08-15 20:23     ` Linus Torvalds
2009-08-15 20:54       ` Linus Torvalds
2009-08-17  1:55         ` Nicolas Pitre
2009-08-26 11:39           ` Pádraig Brady
2017-04-20 21:35             ` galt
2017-04-20 21:38             ` galt
2009-08-17  8:22         ` Andreas Ericsson
2009-08-16  0:06     ` Theodore Tso
2009-08-16 19:25 ` Giuseppe Scrivano
2009-08-16 20:10   ` Linus Torvalds
2009-08-16 22:15     ` Giuseppe Scrivano
2009-08-16 22:47       ` Linus Torvalds
2009-08-17  1:53   ` Pádraig Brady
2009-08-17 10:51     ` Giuseppe Scrivano
2009-08-17 15:44       ` Steven Noonan [this message]
2009-08-17 16:22         ` Linus Torvalds
2009-08-17 21:43           ` Steven Noonan
2009-08-17 17:32         ` Giuseppe Scrivano
  -- strict thread matches above, loose matches on Subject: below --
2009-08-17  7:23 George Spelvin
2009-08-17 14:20 ` Nicolas Pitre
2009-08-17 17:06 ` Nicolas Pitre
2009-08-17 17:20   ` Paolo Bonzini
2009-08-17 18:54   ` George Spelvin
2009-08-17 19:34     ` Nicolas Pitre
2009-08-17 23:12       ` George Spelvin

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