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From: kumon@flab.fujitsu.co.jp
Date: Sat, 2 Dec 2000 09:30:09 +0900
Message-Id: <200012020030.JAA17290@asami.proc.flab.fujitsu.co.jp>
To: Andrew Morton <andrewm@uow.edu.au>
Cc: "Stephen C. Tweedie" <sct@redhat.com>, Alexander Viro <viro@math.psu.edu>,
        Jonathan Hudson <jonathan@daria.co.uk>, linux-kernel@vger.kernel.org
Subject: Re: corruption
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Hi, Andrew,

Andrew Morton writes:
 > - I then killed everything with ALT-SYSRQ-T.  It's been 20 minutes
 >   now and the disk LED is *still* hard on.  This machine has 256 megs
 >   and the hdparm disk bandwidth is 20 megs/sec.
 > 
 > You can observe the latter problem pretty easily by running `misc001' on
 > its own.  Kill it after 20 seconds and the disk remains active for *ages*.
 > Usually ninety seconds.  Long enough to write all physical memory out
 > ten times...

If the benchmark writes blocks completely random, the random writing
performance should be used instead of the bandwidth.  It is tipically
30blk/s to 200blk/s depends on the seek speed.

90 second writing corresponds to 10MB to 72MB dirty buffer
(4K fs block), it is not so crazy.  But 30 minutes is still
too long on 256MB physical memory.

I think they are different, aren't they?

--
Computer Systems Laboratory, Fujitsu Labs.
kumon@flab.fujitsu.co.jp
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