From: Ingo Molnar <mingo@elte•hu>
To: Jonathan Nieder <jrnieder@gmail•com>
Cc: git@vger•kernel.org, "H. Peter Anvin" <hpa@zytor•com>,
Thomas Gleixner <tglx@linutronix•de>,
Peter Zijlstra <a.p.zijlstra@chello•nl>,
Arnaldo Carvalho de Melo <acme@redhat•com>,
Fr?d?ric Weisbecker <fweisbec@gmail•com>,
Pekka Enberg <penberg@cs•helsinki.fi>
Subject: Re: [PATCH] git gc: Speed it up by 18% via faster hash comparisons
Date: Thu, 28 Apr 2011 12:36:50 +0200 [thread overview]
Message-ID: <20110428103650.GA18530@elte.hu> (raw)
In-Reply-To: <20110428063625.GB952@elte.hu>
* Ingo Molnar <mingo@elte•hu> wrote:
> Having said that, it would be nice if someone could test these two patches on a
> modern AMD box, using the perf stat from here:
>
> http://people.redhat.com/mingo/tip.git/README
>
> cd tools/perf/
> make -j install
>
> and do something like this to test git gc's performance:
>
> $ perf stat --sync --repeat 10 ./git gc
>
> ... to see whether these speedups are generic, or somehow Intel CPU specific.
To follow up on this angle, i've now tested both 'git gc' performance
improvement patches on an Opteron box:
#
# Before:
#
Performance counter stats for './git gc' (10 runs):
6400.903957 task-clock # 0.977 CPUs utilized ( +- 0.09% )
1,537 context-switches # 0.000 M/sec ( +- 3.12% )
118 CPU-migrations # 0.000 M/sec ( +- 7.08% )
40,879 page-faults # 0.006 M/sec ( +- 0.03% )
14,768,724,649 cycles # 2.307 GHz ( +- 0.09% )
9,185,135,676 instructions # 0.62 insns per cycle ( +- 0.08% )
1,883,860,739 branches # 294.312 M/sec ( +- 0.16% )
99,800,253 branch-misses # 5.30% of all branches ( +- 0.34% )
6.548348691 seconds time elapsed ( +- 1.01% )
#
# After:
#
Performance counter stats for './git gc' (10 runs):
6078.191492 task-clock # 0.979 CPUs utilized ( +- 0.09% )
1,511 context-switches # 0.000 M/sec ( +- 2.85% )
104 CPU-migrations # 0.000 M/sec ( +- 6.29% )
41,410 page-faults # 0.007 M/sec ( +- 0.04% )
14,024,602,415 cycles # 2.307 GHz ( +- 0.09% )
<not counted> stalled-cycles
11,364,757,635 instructions # 0.81 insns per cycle ( +- 0.06% )
2,612,173,056 branches # 429.762 M/sec ( +- 0.09% )
109,257,789 branch-misses # 4.18% of all branches ( +- 0.74% )
6.209749362 seconds time elapsed ( +- 0.51% )
So they bring an about +5.3% improvement.
Thanks,
Ingo
next prev parent reply other threads:[~2011-04-28 10:37 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-27 22:51 [PATCH] git gc: Speed it up by 18% via faster hash comparisons Ingo Molnar
2011-04-27 23:10 ` Ingo Molnar
2011-04-27 23:18 ` Jonathan Nieder
2011-04-28 6:36 ` Ingo Molnar
2011-04-28 9:31 ` Jonathan Nieder
2011-04-28 10:36 ` Ingo Molnar [this message]
2011-04-28 9:32 ` Dmitry Potapov
2011-04-27 23:32 ` Junio C Hamano
2011-04-28 0:35 ` Ralf Baechle
2011-04-28 8:18 ` Bernhard R. Link
2011-04-28 9:42 ` Andreas Ericsson
2011-04-28 9:55 ` Erik Faye-Lund
2011-04-28 20:19 ` H. Peter Anvin
2011-04-28 6:27 ` Ingo Molnar
2011-04-28 9:17 ` Erik Faye-Lund
2011-04-28 9:33 ` Ingo Molnar
2011-04-28 9:37 ` Ingo Molnar
2011-04-28 9:50 ` Erik Faye-Lund
2011-04-28 10:10 ` Pekka Enberg
2011-04-28 10:19 ` Erik Faye-Lund
2011-04-28 10:30 ` Pekka Enberg
2011-04-28 11:59 ` Erik Faye-Lund
2011-04-28 12:12 ` Pekka Enberg
2011-04-28 12:36 ` Jonathan Nieder
2011-04-28 12:40 ` Erik Faye-Lund
2011-04-28 13:37 ` Ingo Molnar
2011-04-28 15:14 ` Ingo Molnar
2011-04-28 16:00 ` Erik Faye-Lund
2011-04-28 20:32 ` Ingo Molnar
2011-04-29 7:05 ` Alex Riesen
2011-04-29 16:24 ` H. Peter Anvin
2011-04-28 12:16 ` Tor Arntsen
2011-04-28 20:23 ` H. Peter Anvin
2011-04-28 12:17 ` Andreas Ericsson
2011-04-28 12:28 ` Erik Faye-Lund
2011-04-28 10:19 ` Ingo Molnar
2011-04-28 12:02 ` Nguyen Thai Ngoc Duy
2011-04-28 12:18 ` Erik Faye-Lund
2011-04-28 20:20 ` Junio C Hamano
2011-04-28 16:36 ` Dmitry Potapov
2011-04-28 8:52 ` Dmitry Potapov
2011-04-28 9:11 ` Ingo Molnar
2011-04-28 9:31 ` Dmitry Potapov
2011-04-28 9:44 ` Ingo Molnar
2011-04-28 9:38 ` Ingo Molnar
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