On Tue, 6 May 2008, Craig James wrote:
I/O Sched AVG Test1 Test2 --------- ----- ----- ----- cfq 705 695 715 noop 758 769 747 deadline 741 705 775 anticipatory 494 477 511
Interesting. That contrasts with some tests I did a while back on a 16-disc RAID-0, where noop, deadline, and anticipatory were all identical in performance, with cfq being significantly slower. Admittedly, the disc test was single-process, which is probably why the anticipatory behaviour didn't kick in. You are seeing a little bit of degradation with cfq - I guess it's worse the bigger the disc subsystem you have.
Matthew -- Matthew: That's one of things about Cambridge - all the roads keep changing names as you walk along them, like Hills Road in particular. Sagar: Yes, Sidney Street is a bit like that too. Matthew: Sidney Street *is* Hills Road.