Messages in this thread | | | Subject | Re: [PATCH 0/2] block/SCSI MQ: two RESTART related patches | From | John Garry <> | Date | Tue, 17 Oct 2017 16:47:23 +0100 |
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On 17/10/2017 06:12, Ming Lei wrote: > On Tue, Oct 17, 2017 at 01:04:16PM +0800, Ming Lei wrote: >> Hi Jens, >> >> The 1st patch runs idle hctx after dealy in scsi_mq_get_budget(), >> so that we can keep same behaviour with before, and it can be >> thought as a fix. >> >> The 2nd patch cleans up RESTART, and removes handling for TAG_SHARED >> from current blk-mq's RESTART mechanism because SCSI_MQ can covers its >> restart by itself, so that no need to handle TAG_SHARED in blk-mq >> RESTART. And >20% IOPS boost is observed in my rand read test over >> scsi_debug. >> >> John, please test this two patches and see if it may improve your SAS >> IO performance, and you can find the two patches in the following branch: >> >> https://github.com/ming1/linux/commits/blk_mq_improve_restart_V1 >
Hi Ming,
As requested, here's my figures for blk_mq_improve_restart_V1: without default SCSI_MQ, deadline scheduler, CONFIG PREEMPT off read, rw, write IOPS 989K, 113K/113K, 835K
with default SCSI_MQ, mq-deadline scheduler, CONFIG PREEMPT off read, rw, write IOPS 738K, 130K/130K, 686K
For axboe for-next tip (21ed538): without default SCSI_MQ, deadline scheduler, CONFIG PREEMPT off read, rw, write IOPS 977K, 117K/117K, 821K
with default SCSI_MQ, mq-deadline scheduler, CONFIG PREEMPT off read, rw, write IOPS 733K, 128K/128K, 676K
All cases do not have LLDD mq exposed/enabled. So unfortunately not much difference with your branch.
cheers, John
> Forget to mention, you need to either pull the above branch directly > or apply the two patches against for-next branch of Jens' block > tree: > > git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git #for-next >
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