Date: Tue, 26 Feb 2008 09:32:16 +0000 From: Alex Zbyslaw <xfb52@dial.pipex.com> To: Tim Kientzle <kientzle@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: emulate an end-of-media Message-ID: <47C3DCA0.5000205@dial.pipex.com> In-Reply-To: <47C3A228.7090703@freebsd.org> References: <op.t63j2veq724k7f@martin> <20080225154455.4822e72a@bhuda.mired.org> <47C33384.6040701@dial.pipex.com> <200802252243.m1PMhTeq016201@fire.js.berklix.net> <47C3A228.7090703@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Tim Kientzle wrote:
>> Why compress? It's ancient technology and will be vastly outperformed
>
>
> Yes, gzip or bzip2 compress better, but they also:
> * Are a lot slower.
> * Use a lot more data memory.
> * Require a lot more code.
I don't understand what "a lot more code" has to do with anything.
gzip/zlib is part of base and portable.
In my quick tests on some real dump files, *if* you are able to specify
the compression quality, then gzip -1 is both faster and better
compressing than compress. If I'm reading time correctly, then gzip at
any compression level used less memory than compress. bzip2 uses more
memory but -9 always uses roughly the same amount of memory: ~9Mb.
180672 -r--r----- 1 root alex - 184893440 Feb 26 09:08
cartman-root.dump.0
131 {root @ ren} # time compress cartman-root.dump.0
7.948u 0.264s 0:08.93 91.8% 15+744k 0+725io 0pf+0w
92896 -r--r----- 1 root alex - 95051115 Feb 26 09:08
cartman-root.dump.0.Z
134 {root @ ren} # time gzip -1 cartman-root.dump.0
6.543u 0.288s 0:06.93 98.4% 56+585k 1+549io 2pf+0w
70368 -r--r----- 1 root alex - 71979780 Feb 26 09:08
cartman-root.dump.0.gz
137 {root @ ren} # time gzip -9 cartman-root.dump.0
44.588u 0.304s 0:46.53 96.4% 56+584k 0+494io 0pf+0w
63344 -r--r----- 1 root alex - 64800326 Feb 26 09:08
cartman-root.dump.0.gz
140 {root @ ren} # time bzip2 cartman-root.dump.0
51.327u 0.398s 0:53.44 96.7% 30+9638k 3+471io 3pf+0w
60384 -r--r----- 1 root alex - 61769750 Feb 26 09:08
cartman-root.dump.0.bz2
And for a largely text filesystem dump:
58352 -r--r----- 1 root alex - 59699200 Feb 26 09:13 cartman-var.dump.0
152 {root @ ren} # time compress cartman-var.dump.0
2.179u 0.102s 0:02.31 98.2% 15+737k 0+156io 1pf+0w
20000 -r--r----- 1 root alex - 20456769 Feb 26 09:13
cartman-var.dump.0.Z
155 {root @ ren} # time gzip -1 cartman-var.dump.0
1.441u 0.069s 0:01.53 98.0% 57+592k 0+116io 0pf+0w
14992 -r--r----- 1 root alex - 15328819 Feb 26 09:13
cartman-var.dump.0.gz
158 {root @ ren} # time gzip -9 cartman-var.dump.0
4.807u 0.062s 0:04.89 99.3% 56+583k 0+104io 0pf+0w
13424 -r--r----- 1 root alex - 13727598 Feb 26 09:13
cartman-var.dump.0.gz
161 {root @ ren} # time bzip2 cartman-var.dump.0
28.057u 0.132s 0:28.97 97.2% 30+9629k 0+91io 0pf+0w
11792 -r--r----- 1 root alex - 12052157 Feb 26 09:13
cartman-var.dump.0.bz2
--Alex
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47C3DCA0.5000205>