From: Giuseppe Scrivano <gscrivano@gnu.org>
To: "Pádraig Brady" <P@draigBrady.com>
Cc: 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 12:51:17 +0200 [thread overview]
Message-ID: <8763cmemsa.fsf@master.homenet> (raw)
In-Reply-To: <4A88B80D.40804@draigBrady.com> ("Pádraig Brady"'s message of "Mon, 17 Aug 2009 02:53:17 +0100")
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
next prev parent reply other threads:[~2009-08-17 10:52 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 [this message]
2009-08-17 15:44 ` Steven Noonan
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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