Re: Performance regression in IO scheduler still there

From: Jeff Moyer
Date: Fri Nov 06 2009 - 09:15:24 EST

Corrado Zoccolo <czoccolo@xxxxxxxxx> 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?

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