From: Linus Torvalds <torvalds@osdl.org>
To: Mike Taht <mike.taht@timesys.com>
Cc: Matt Mackall <mpm@selenic.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
git@vger.kernel.org
Subject: Re: Mercurial 0.3 vs git benchmarks
Date: Mon, 25 Apr 2005 20:04:54 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.58.0504251938210.18901@ppc970.osdl.org> (raw)
In-Reply-To: <426DA7B5.2080204@timesys.com>
On Mon, 25 Apr 2005, Mike Taht wrote:
>
> One difference is probably - mercurial appears to be using zlib's
> *default* compression of 6....
>
> using zlib compression of 9 really impacts git...
I agree that it will hurt for big changes, but since I really do believe
that most changes are just a couple of files, I don't believe it matters
for those.
I forget what the exact numbers were, but I did some timings on plain
"gzip", and it basically said that doing gzip on a medium-sized file was
not that different for -6 and -9. Why? Because most of the overhead was
elsewhere ;)
Oh, well, I just re-created some numbers. This wasn't exactly what I did
last time I tested it, but it's conceptually the same thing:
torvalds@ppc970:~> time gzip -9 < v2.6/linux/kernel/sched.c > /dev/null
real 0m0.018s
user 0m0.018s
sys 0m0.000s
torvalds@ppc970:~> time gzip -6 < v2.6/linux/kernel/sched.c > /dev/null
real 0m0.015s
user 0m0.013s
sys 0m0.001s
ie there's a 0.003 second difference, which is certainly noticeable, and
would be hugely noticeable if you did a lot of these. But in my world-view
(which is what git is optimized for), the common case is that you usually
end up compressing maybe five-ten files, so the _compression_ overhead is
not that huge compared to all the other stuff.
But yes, testing git on big changes will test exactly the things that git
isn't optimized for. I think git will normally hold up pretty well (ie it
will still beat anything that isn't designed for speed, and will be
comparable to things that _are_), but it's not what I'm interested in
optimizing for.
That said - these days we can trivially change over to a "zlib -6"
compression, and nothing should ever notice. So if somebody wants to
test it, it should be fairly easy to just compare side-by-side: the
results should be identical.
The easiest test-case is Andrew's 198-patch patch-bomb on linux-kernel a
few weeks ago: they all apply cleanly to 2.6.12-rc2 (in order), and you
can use my "dotest" script to automate the test..
Linus
next prev parent reply other threads:[~2005-04-26 3:03 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-26 0:41 Mercurial 0.3 vs git benchmarks Matt Mackall
2005-04-26 1:49 ` Daniel Phillips
2005-04-26 2:08 ` Linus Torvalds
2005-04-26 2:30 ` Mike Taht
2005-04-26 3:04 ` Linus Torvalds [this message]
2005-04-26 4:00 ` Linus Torvalds
2005-04-26 11:13 ` Chris Mason
2005-04-26 15:09 ` Magnus Damm
2005-04-26 15:38 ` Chris Mason
2005-04-26 16:23 ` Magnus Damm
2005-04-26 18:18 ` Chris Mason
2005-04-26 20:56 ` Andrew Morton
2005-04-26 21:07 ` Linus Torvalds
2005-04-26 22:50 ` H. Peter Anvin
2005-04-26 22:56 ` Andrew Morton
2005-04-26 23:43 ` H. Peter Anvin
2005-04-27 15:01 ` Florian Weimer
2005-04-27 15:13 ` Thomas Glanzmann
2005-04-27 18:54 ` H. Peter Anvin
2005-04-27 19:01 ` Thomas Glanzmann
2005-04-27 19:57 ` Theodore Ts'o
2005-04-27 20:06 ` Thomas Glanzmann
2005-04-27 20:35 ` H. Peter Anvin
2005-04-27 20:39 ` Thomas Glanzmann
2005-04-27 20:47 ` Florian Weimer
2005-04-27 20:55 ` Florian Weimer
2005-04-27 21:04 ` H. Peter Anvin
2005-04-27 21:06 ` Florian Weimer
2005-04-27 21:32 ` Theodore Ts'o
2005-04-27 19:55 ` Theodore Ts'o
2005-04-27 6:34 ` Ingo Molnar
2005-04-27 21:10 ` Bill Davidsen
2005-04-27 21:39 ` Linus Torvalds
2005-04-26 16:42 ` Linus Torvalds
2005-04-26 17:39 ` Chris Mason
2005-04-26 19:52 ` Chris Mason
2005-04-26 18:15 ` H. Peter Anvin
2005-04-26 20:30 ` Bill Davidsen
2005-04-26 16:11 ` Bill Davidsen
2005-04-26 4:01 ` Matt Mackall
2005-04-26 4:20 ` Linus Torvalds
2005-04-26 4:09 ` Chris Wedgwood
2005-04-26 4:22 ` Andreas Gal
2005-04-26 4:22 ` Linus Torvalds
2005-04-29 6:01 ` Mercurial 0.4b vs git patchbomb benchmark Matt Mackall
2005-04-29 6:40 ` Sean
2005-04-29 7:40 ` Matt Mackall
2005-04-29 8:40 ` Sean
2005-04-29 14:34 ` Linus Torvalds
2005-04-29 15:18 ` Morten Welinder
2005-04-29 16:52 ` Matt Mackall
2005-05-02 16:10 ` Bill Davidsen
2005-05-02 19:02 ` Sean
2005-05-02 22:02 ` Linus Torvalds
2005-05-02 22:30 ` Matt Mackall
2005-05-02 22:49 ` Linus Torvalds
2005-05-03 0:00 ` Matt Mackall
2005-05-03 2:48 ` Linus Torvalds
2005-05-03 3:29 ` Matt Mackall
2005-05-03 4:18 ` Linus Torvalds
2005-05-03 4:24 ` Linus Torvalds
2005-05-03 4:27 ` Matt Mackall
2005-05-03 8:45 ` Chris Wedgwood
2005-04-29 15:44 ` Tom Lord
2005-04-29 15:58 ` Linus Torvalds
2005-04-29 17:34 ` Tom Lord
2005-04-29 17:56 ` Linus Torvalds
2005-04-29 18:08 ` Tom Lord
2005-04-29 18:33 ` Sean
2005-04-29 18:54 ` Tom Lord
2005-04-29 19:13 ` Sean
2005-04-29 19:22 ` Tom Lord
2005-04-29 19:28 ` Tom Lord
2005-04-29 19:47 ` Noel Maddy
2005-04-29 19:54 ` Tom Lord
2005-04-29 20:13 ` Andrew Timberlake-Newell
2005-04-29 20:26 ` Tom Lord
2005-04-29 20:57 ` Andrew Timberlake-Newell
2005-04-29 20:16 ` Morgan Schweers
2005-04-29 20:21 ` Noel Maddy
2005-04-29 20:42 ` git network protocol David Lang
2005-04-29 21:15 ` Daniel Barkalow
2005-04-29 20:44 ` Mercurial 0.4b vs git patchbomb benchmark Tom Lord
2005-04-29 21:57 ` Denys Duchier
2005-04-29 20:29 ` Signed commit vulnerabilities? (was: Mercurial 0.4b vs git patchbomb benchmark) Kevin Smith
2005-04-29 21:45 ` Mercurial 0.4b vs git patchbomb benchmark Horst von Brand
2005-05-02 21:06 ` Tom Lord
2005-05-03 0:24 ` Kevin Smith
2005-05-02 16:15 ` Bill Davidsen
2005-04-29 16:37 ` Matt Mackall
2005-04-29 17:09 ` Linus Torvalds
2005-04-29 19:12 ` Matt Mackall
2005-04-29 19:50 ` Linus Torvalds
2005-04-29 20:23 ` Matt Mackall
2005-04-29 20:49 ` Linus Torvalds
2005-04-29 21:20 ` Matt Mackall
2005-04-29 16:46 ` Bill Davidsen
2005-04-29 20:19 ` Andrea Arcangeli
2005-04-29 22:30 ` Olivier Galibert
2005-04-29 22:47 ` Andrea Arcangeli
2005-04-29 20:30 ` Andrea Arcangeli
2005-04-29 20:39 ` Matt Mackall
2005-04-30 2:52 ` Andrea Arcangeli
2005-04-30 15:20 ` Matt Mackall
2005-04-30 16:37 ` Andrea Arcangeli
2005-05-02 15:49 ` Bill Davidsen
2005-05-02 16:14 ` Valdis.Kletnieks
2005-05-03 17:40 ` Bill Davidsen
2005-05-04 2:10 ` Mercurial 0.4b vs git patchbomb benchmark (/usr/bin/env again) David A. Wheeler
2005-05-02 16:17 ` Mercurial 0.4b vs git patchbomb benchmark Andrea Arcangeli
2005-05-02 16:31 ` Linus Torvalds
2005-05-02 17:18 ` Daniel Jacobowitz
2005-05-02 17:32 ` Linus Torvalds
2005-05-02 18:17 ` Edgar Toernig
2005-05-02 20:54 ` Sam Ravnborg
2005-05-02 17:20 ` Ryan Anderson
2005-05-02 17:31 ` Linus Torvalds
2005-05-02 21:17 ` Kyle Moffett
2005-05-03 17:43 ` Bill Davidsen
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