Re: RAID 10 Benchmark with different I/O schedulers

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.