From: Mike Taht <mike.taht@timesys.com>
To: git@vger.kernel.org
Subject: Performance of various compressors
Date: Wed, 20 Apr 2005 22:06:38 -0700 [thread overview]
Message-ID: <426734DE.3040606@timesys.com> (raw)
I started rolling a tool to measure various aspects of git performance.
I will start looking at merge next, and at workloads different from the
kernel (gcc4 anyone?) ...
The only data points worth sharing a this point are:
That doing the compression at a level of 3, rather than the max of 9,
cuts the cpu time required for a big git commit by over half, and that
that actually translates into a win on the I/O to disk. (these tests
were performed on a dual opteron 842)
The benefits of compression aren't very much for git right now.
And: A big git commit is I/O bound. But we knew that. Maybe it's
possible to make it less I/O bound.
Git branch: 7a4c67965de68ae7bc7aa1fde33f8eb9d8114697
Tree: 2.6.11.7 source tree
Branch: N/a
Merge File: N/a
HW: dual opteron 242
Mem: 1GB
Disk: seagate barracuda
Filesystem: Reiser3
Git add: N/a
Cache: Hot
Git Commit: 44.97user 5.94system 1:45.24elapsed 48%CPU
Git Merge:
Options:
Feature: Test of compression=9 (std git)
du -s .git/objects 110106 # du is probably not the right thing
du -s --apparent-size .git/objects 58979
Git branch: 9e272677621c91784cf2533123a41745178f0701
Tree: 2.6.11.7 source tree
Branch: N/a
Merge File: N/a
HW: dual opteron 242
Mem: 1GB
Disk: seagate barracuda
Disk mode: udma5
Filesystem: Reiser3
Git add: N/a
Cache: Hot
Git Commit: 16.79user 6.15system 1:21.92elapsed 28%CPU
Git Merge:
Options:
Feature: Test of compression=3 (std git)
du -s .git/objects 115218
du -s --apparent-size .git/objects 64274
There's some variety in the best/worst case timings for I/O for the
compressor=3 case...
16.79user 6.15system 1:21.92elapsed 28%CPU
16.68user 5.71system 1:13.19elapsed 30%CPU
--
Mike Taht
lastly -
Timings of git commit with tmpfs (note, these were done with an ancient,
5 hour old version of git and the script)
Hot cache, tmpfs .git compression=9
44.97user 2.76system 0:47.72elapsed 100%CPU
Hot cache, tmpfs .git, compression=6
Wed Apr 20 20:18:11 PDT 2005
23.55user 2.83system 0:26.36elapsed 100%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (0major+568680minor)pagefaults 0swaps
109620 .git/objects
58618 .git/objects
next reply other threads:[~2005-04-21 5:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-21 5:06 Mike Taht [this message]
2005-04-21 5:14 ` Performance of various compressors Mike Taht
2005-04-21 5:22 ` [PATCH] experimental - " Mike Taht
2005-04-21 10:23 ` HOWTO: PATCH: don't hardcode path-to-bash, use sys/limits.h Klaus Robert Suetterlin
2005-04-21 14:31 ` Alecs King
2005-04-21 19:42 ` [PATCH] #!/bin/sh --> #!/usr/bin/env bash Alecs King
2005-04-22 7:37 ` H. Peter Anvin
2005-04-23 2:34 ` David A. Wheeler
2005-04-23 6:16 ` H. Peter Anvin
2005-04-22 20:38 ` Performance of various compressors Aaron Lehmann
2005-04-25 12:17 ` git I/O performance (was: Performance of various compressors) Klaus Robert Suetterlin
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