Messages in this thread | | | Date | Fri, 06 Apr 2012 11:39:09 -0600 | From | Jens Axboe <> | Subject | Re: [PATCH]block: make auto block plug flush threshold per-disk based |
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On 2012-04-06 11:27, Shaohua Li wrote: > We do auto block plug flush to reduce latency, the threshold is 16 > requests. This works well if the task is accessing one or two drives. > The problem is if the task is accessing a raid 0 device and the raid > disk number is big, say 8 or 16, 16/8 = 2 or 16/16=1, we will have > heavy lock contention. > > This patch makes the threshold per-disk based. The latency should be > still ok accessing one or two drives. The setup with application > accessing a lot of drives in the meantime uaually is big machine, > avoiding lock contention is more important, because any contention > will actually increase latency.
Thanks, applied. It should have been per-queue all along, so this makes a lot of sense.
-- Jens Axboe
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