From: Andrew Morton <akpm@zip.com.au>
To: Steve Lord <lord@sgi.com>
Cc: Ben Israel <ben@genesis-one.com>, linux-kernel@vger.kernel.org
Subject: Re: File System Performance
Date: Mon, 12 Nov 2001 13:43:37 -0800 [thread overview]
Message-ID: <3BF04289.8FC8B7B7@zip.com.au> (raw)
In-Reply-To: <3BF03402.87D44589@zip.com.au>, <3BF02702.34C21E75@zip.com.au>, <00b201c16b81$9d7aaba0$5101a8c0@pbc.adelphia.net> <3BEFF9D1.3CC01AB3@zip.com.au> <00da01c16ba2$96aeda00$5101a8c0@pbc.adelphia.net> <3BF02702.34C21E75@zip.com.au> <1005595583.13307.5.camel@jen.americas.sgi.com> <3BF03402.87D44589@zip.com.au> <1005600431.13303.10.camel@jen.americas.sgi.com>
Steve Lord wrote:
>
> ...
>
> I tried an experiment which puzzled me somwhat:
>
> > mount /xfs
> > cd /xfs/lord/xfs-linux
> > time tar cf /dev/null linux
>
> real 0m7.743s
> user 0m0.510s
> sys 0m1.380s
>
> > hdparm -t /dev/sda5
>
> /dev/sda5:
> Timing buffered disk reads: 64 MB in 3.76 seconds = 17.02 MB/sec
>
> > du -sk linux
> 173028 linux
>
> The tar got ~21 Mbytes/sec.
>
It's tar. It cheats. It somehow detects that the
output is /dev/null, and so it doesn't read the input files.
I think.
akpm-1:/opt> l
total 562884
-rw-r--r-- 1 akpm akpm 575785370 Apr 8 2001 backup
akpm-1:/opt> time tar cf /dev/null backup
tar cf /dev/null backup 0.02s user 0.00s system 4% cpu 0.422 total
That's 570 megs in 0.4 seconds. Impressive.
So I just use
time (find dir -type f | xargs cat > /dev/null)
> In our cvs tree cmd/xfsprogs/tests/src/fsstress.c
OK, thanks.
-
next prev parent reply other threads:[~2001-11-12 21:45 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-12 13:54 File System Performance Ben Israel
2001-11-12 16:33 ` Andrew Morton
2001-11-12 17:50 ` Ben Israel
2001-11-12 19:46 ` Andrew Morton
2001-11-12 19:59 ` Richard Gooch
2001-11-12 23:07 ` Mike Fedyk
2001-11-13 0:04 ` Richard Gooch
2001-11-13 0:08 ` Mike Fedyk
2001-11-13 0:26 ` Richard Gooch
2001-11-13 0:47 ` Mike Castle
2001-11-13 1:28 ` Mike Fedyk
2001-11-13 6:34 ` Richard Gooch
2001-11-13 20:56 ` Andreas Dilger
2001-11-13 7:45 ` Andreas Dilger
2001-11-12 20:06 ` Steve Lord
2001-11-12 20:41 ` Andrew Morton
2001-11-12 21:27 ` Steve Lord
2001-11-12 21:43 ` Andrew Morton [this message]
2001-11-12 21:45 ` Steve Lord
2001-11-12 21:48 ` Linus Torvalds
2001-11-12 22:11 ` Lionel Bouton
2001-11-12 19:41 ` Gérard Roudier
2001-11-12 22:14 ` Linus Torvalds
2001-11-12 22:30 ` Ragnar Kjørstad
2001-11-12 22:36 ` Andrew Morton
2001-11-12 23:04 ` Mike Castle
2001-11-13 9:56 ` Peter Wächtler
2001-11-13 9:41 ` Henning P. Schmiedehausen
2001-11-12 22:16 ` Andrew Morton
2001-11-12 22:26 ` Steve Lord
2001-11-12 22:32 ` Lionel Bouton
2001-11-12 22:45 ` Alan Cox
2001-11-12 22:39 ` Alan Cox
2001-11-12 22:39 ` Xavier Bestel
2001-11-12 22:46 ` Mike Castle
2001-11-12 21:53 ` Lionel Bouton
2001-11-13 0:17 ` Andreas Dilger
2001-11-13 0:40 ` Peter J . Braam
2001-11-13 20:46 ` Andreas Dilger
2001-11-16 22:07 ` Peter J . Braam
2001-11-16 23:14 ` Mike Fedyk
2001-11-12 16:40 ` Ben Israel
2001-11-12 17:29 ` Andrew Morton
-- strict thread matches above, loose matches on Subject: below --
2001-11-12 22:36 Grant Erickson
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