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From: Jun He <jhe@cs.wisc.edu>
To: fio@vger.kernel.org
Subject: io_size usage
Date: Wed, 9 Dec 2015 02:50:40 +0000 (UTC)	[thread overview]
Message-ID: <loom.20151209T033523-799@post.gmane.org> (raw)

Hi all,
I think there is a bug for io_size. 

For example, I want to write 16KB data to a file of size 8KB (so each block is
written twice) and I have the following job file:

[global]
ioengine=sync
rw=write
bs=4kb
size=8kb
io_size=32kb

[job1]
write_iolog=iolog.1


After running, iolog.1 will contain the following contents:

fio version 2 iolog
job1.0.0 add
job1.0.0 open
job1.0.0 write 0 4096
job1.0.0 write 4096 4096
job1.0.0 close

This shows that each block has been only written once. 

If I change the ioengine to libaio, iolog.1 will contain:

fio version 2 iolog
job1.0.0 add
job1.0.0 open
job1.0.0 write 0 4096
job1.0.0 write 4096 4096
job1.0.0 close
job1.0.0 open
job1.0.0 write 0 4096
job1.0.0 write 4096 4096
job1.0.0 close
job1.0.0 open
job1.0.0 write 0 4096
job1.0.0 write 4096 4096
job1.0.0 close
job1.0.0 open
job1.0.0 write 0 4096
job1.0.0 write 4096 4096
job1.0.0 close


Bug or wrong usage?

Thanks,
Jun




             reply	other threads:[~2015-12-09  2:55 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-09  2:50 Jun He [this message]
2015-12-10  6:56 ` io_size usage Sitsofe Wheeler
2015-12-10 15:14   ` Jun He

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