Hi,
This type of conf file is useful for testing disk cache speeds. But it
exposes an fio bug. The workaround is to use rw=randread and norandommap=1
(to avoid some cpu overhead).
With this conf file:
[hdc-cache_speed]
filename=/dev/hdc
rw=read
bs=64k
size=64k
ioengine=libaio
iodepth=8
runtime=10
bwavgtime=5000
time_based=1
direct=1
thread=1
ioscheduler=noop
write_iolog=cache_speed.log
we get this as an io_log (truncated):
fio version 2 iolog
/dev/hdc add
/dev/hdc open
/dev/hdc read 0 65536
/dev/hdc read 65536 65536
/dev/hdc read 131072 65536
/dev/hdc read 196608 65536
/dev/hdc read 262144 65536
/dev/hdc read 327680 65536
/dev/hdc read 393216 65536
/dev/hdc read 458752 65536
/dev/hdc close
/dev/hdc open
/dev/hdc read 0 65536
/dev/hdc read 65536 65536
/dev/hdc read 131072 65536
/dev/hdc read 196608 65536
/dev/hdc read 262144 65536
/dev/hdc read 327680 65536
/dev/hdc read 393216 65536
/dev/hdc read 458752 65536
/dev/hdc close
...
fio shouldn't write past 65536 because size=64k.
Sorry, I'm not working out the head fio tree right now, so this may already
be fixed, but I wanted to let you know just in case.
-Shawn
Received on Thu May 15 2008 - 03:40:58 CEST
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