Ubuntu
linux package

  1. Bug #595047
  2. Comment #95

Comment 95 for bug 595047

Revision history for this message
In , mathieu.desnoyers (mathieu.desnoyers-linux-kernel-bugs) wrote :

I just created a fio job file which acts like a "ls" executed while doing a large dd. It looks like the anticipatory I/O scheduler was causing those delays for me.

The results for the ls-like jobs are interesting :

I/O scheduler runt-min (msec) runt-max (msec)
noop 41 10563
anticipatory 63 8185
deadline 52 33387
cfq 43 1420

Is it me or all I/O schedulers except cfq generate unexpectedly high latency ?

Details here (including fio job file) :

http://lkml.org/lkml/2009/1/18/198

Mathieu