Messages in this thread | | | Date | Tue, 16 Mar 2004 17:36:18 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH] per-backing dev unplugging #2 |
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Jeremy Higdon wrote:
>| Hi, >| >| Final version, unless something stupid pops up. Changes: >| >| - Adapt to 2.6.4-mm1 >| - Cleaned up the dm bits, much nicer with the lockless unplugging >| (thanks Joe) >| - md and loop unplugging, stacked devices should unplug their targets. >| Otherwise they'll end up waiting for the unplug timer, which sucks. >| - XFS fixed up, I hope. XFS folks still encouraged to look at this, >| looks better this time around though (and works, I tested). >| - blk_run_* inlined in blkdev.h >| >| Against 2.6.4-mm1 (note you need other attached patch to boot it). > >I got a chance to try this. > >It makes a huge improvement. > >Prior to the last per-cpu patch, I was getting about 75000 to 80000 >IOPS at 100% cpu usage. > >With the per-cpu patch, that went up to 110000 IOPS at 100% CPU. > >With this patch, I'm seeing 200000 IOPS at about 65% CPU usage. > >So it makes a tremendous improvement in I/O scalability, dramatically >improving performance in small size I/O, high I/O count workloads. > >My tests were on an 8 CPU x 1300 MHz Altix with 64 disks. > >
Nice - so if you had enough IO capacity to saturate the CPUs it might come close to a 4x improvement - and this sounds like one of your baby systems?
I wonder why nobody's complained about this before?
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