From: Richard Kennedy <richard@rsk.demon.co.uk>
To: fio <fio@vger.kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Subject: fio mmap writes much slower than default writes
Date: Thu, 16 Jul 2009 14:40:07 +0100 [thread overview]
Message-ID: <1247751607.2689.63.camel@localhost.localdomain> (raw)
Running tests of fio write with sizes that are less than the write cache
size I'm seeing a big slow down when using mmap. I'm running the tests
on linux 2.6.31-rc* x86_64.
Typical results with default writes :-
fio size=300m rw=write
write: io=300MiB, bw=314MiB/s, iops=80,418, runt= 955msec
with mmap :-
fio size=300m rw=write ioengine=mmap
write: io=300MiB, bw=55,732KiB/s, iops=13,933, runt= 5512msec
Is this expected or is it indicative of a problem somewhere?
regards
Richard
next reply other threads:[~2009-07-16 13:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-16 13:40 Richard Kennedy [this message]
2009-07-18 6:18 ` fio mmap writes much slower than default writes Jens Axboe
2009-07-18 13:58 ` Richard Kennedy
2009-07-18 14:20 ` Jens Axboe
2009-07-18 14:39 ` Jens Axboe
2009-07-18 14:50 ` Richard Kennedy
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