Re: Performance regression in IO scheduler still there

Jeff Moyer
2009-11-06T14:15:11Z

Corrado Zoccolo <czoccolo@gmail.com> writes:

> Hi Jeff,
> what hardware are you using for tests?
> I see aggregated random read bandwidth is larger than sequential read
> bandwidth, and write bandwidth greater than read.
> Is this a SAN with multiple independent spindles?

Yeah, this is a single path to an HP EVA storage array. There are 24 or
so disks striped in the pool used to create the volume I am using. Jan,
could you repeat your tests with /sys/block/sdX/queue/iosched/low_latency
set to 0?

Cheers,
Jeff