Re: random i/o speedup weirdness

From: <>
Date: Wed, 30 May 2007 17:50:35 +0200

> Instead I opted to try and fix the behaviour. It likely wont be perfect,
> but some testing here shows that the IO at the end differs no more than
> the noise during the entire run.
> So can I ask you to repeat the test with a current version of fio? I'd
> suggest just grabbing:

Thank you very much, this produces a much flatter and more consistent
result. The "summary screen" of fio is still wrong, but the "speedup"
towards the end of the test is much, much less "extreme".

root_at_pcitfiol25:/mnt/scratch/fio/new-fio# /usr/src/fio/fio sdc1.conf
/dev/sdc1: (g=0): rw=randread, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=2
Starting 1 process
Jobs: 1 (f=1): [r] [100.0% done] [ 0/ 0 kb/s] [eta 00m:00s]0s]
/dev/sdc1: (groupid=0, jobs=1): err= 0: pid=15443
  read : io=7,534MiB, bw=3,081KiB/s, iops=752, runt=2563805msec


Run status group 0 (all jobs):
   READ: io=7,534MiB, aggrb=3,081KiB/s, minb=3,081KiB/s, maxb=3,081KiB/s, mint=2563805msec, maxt=2563805msec

(why are min, max and average all the same values? or am I reading this
wrong? the 'real' number would be about 700KiB/s for this disk)

Hmmm, on second thought I only just noticed that this is about the right
value (from the cut-out part of the above output):

    bw (KiB/s) : min= 611, max= 1417, per=23.00%, avg=708.51,

Received on Wed May 30 2007 - 17:50:35 CEST

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