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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Christoph Hellwig <hch@infradead.org>, Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@fb.com>,
	linux-block@vger.kernel.org,
	Bart Van Assche <bart.vanassche@sandisk.com>,
	Laurence Oberman <loberman@redhat.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH V2 00/20] blk-mq-sched: improve SCSI-MQ performance
Date: Fri, 11 Aug 2017 07:25:50 -0700	[thread overview]
Message-ID: <1502461550.2647.4.camel@HansenPartnership.com> (raw)
In-Reply-To: <20170811081135.GA4260@infradead.org>

On Fri, 2017-08-11 at 01:11 -0700, Christoph Hellwig wrote:
> [+ Martin and linux-scsi]
> 
> Given that we need this big pile and a few bfq fixes to avoid
> major regressesions I'm tempted to revert the default to scsi-mq
> for 4.14, but bring it back a little later for 4.15.
> 
> What do you think?  Maybe for 4.15 we could also do it through the
> block tree where all the fixes will be queued.

Given the severe workload regressions Mel reported, I think that's
wise.

I also think we wouldn't have found all these problems if it hadn't
been the default, so the original patch was the best way of trying to
find out if we were ready for the switch and forcing all the issues
out.

Thanks,

James

  reply	other threads:[~2017-08-11 14:25 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-05  6:56 [PATCH V2 00/20] blk-mq-sched: improve SCSI-MQ performance Ming Lei
2017-08-05  6:56 ` [PATCH V2 01/20] blk-mq-sched: fix scheduler bad performance Ming Lei
2017-08-09  0:11   ` Omar Sandoval
2017-08-09  2:32     ` Ming Lei
2017-08-09  7:11       ` Omar Sandoval
2017-08-21  8:18         ` Ming Lei
2017-08-23  7:48         ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 02/20] sbitmap: introduce __sbitmap_for_each_set() Ming Lei
2017-08-22 18:28   ` Bart Van Assche
2017-08-24  3:57     ` Ming Lei
2017-08-25 21:36       ` Bart Van Assche
2017-08-26  8:43         ` Ming Lei
2017-08-22 18:37   ` Bart Van Assche
2017-08-24  4:02     ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 03/20] blk-mq: introduce blk_mq_dispatch_rq_from_ctx() Ming Lei
2017-08-22 18:45   ` Bart Van Assche
2017-08-24  4:52     ` Ming Lei
2017-08-25 21:41       ` Bart Van Assche
2017-08-26  8:47         ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 04/20] blk-mq-sched: move actual dispatching into one helper Ming Lei
2017-08-22 19:50   ` Bart Van Assche
2017-08-05  6:56 ` [PATCH V2 05/20] blk-mq-sched: improve dispatching from sw queue Ming Lei
2017-08-22 19:55   ` Bart Van Assche
2017-08-23 19:58     ` Jens Axboe
2017-08-24  5:52     ` Ming Lei
2017-08-22 20:57   ` Bart Van Assche
2017-08-24  6:12     ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 06/20] blk-mq-sched: don't dequeue request until all in ->dispatch are flushed Ming Lei
2017-08-22 20:09   ` Bart Van Assche
2017-08-24  6:18     ` Ming Lei
2017-08-23 19:56   ` Jens Axboe
2017-08-24  6:38     ` Ming Lei
2017-08-25 10:19       ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 07/20] blk-mq-sched: introduce blk_mq_sched_queue_depth() Ming Lei
2017-08-22 20:10   ` Bart Van Assche
2017-08-05  6:56 ` [PATCH V2 08/20] blk-mq-sched: use q->queue_depth as hint for q->nr_requests Ming Lei
2017-08-22 20:20   ` Bart Van Assche
2017-08-24  6:39     ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 09/20] blk-mq: introduce BLK_MQ_F_SHARED_DEPTH Ming Lei
2017-08-22 21:55   ` Bart Van Assche
2017-08-23  6:46     ` Hannes Reinecke
2017-08-24  6:52     ` Ming Lei
2017-08-25 22:23       ` Bart Van Assche
2017-08-26  8:53         ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 10/20] blk-mq-sched: introduce helpers for query, change busy state Ming Lei
2017-08-22 20:41   ` Bart Van Assche
2017-08-23 20:02     ` Jens Axboe
2017-08-24  6:55       ` Ming Lei
2017-08-24  6:54     ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 11/20] blk-mq: introduce helpers for operating ->dispatch list Ming Lei
2017-08-22 20:43   ` Bart Van Assche
2017-08-24  0:59     ` Damien Le Moal
2017-08-24  7:10       ` Ming Lei
2017-08-24  7:42         ` Damien Le Moal
2017-08-24  6:57     ` Ming Lei
2017-08-05  6:56 ` [PATCH V2 12/20] blk-mq: introduce pointers to dispatch lock & list Ming Lei
2017-08-05  6:56 ` [PATCH V2 13/20] blk-mq: pass 'request_queue *' to several helpers of operating BUSY Ming Lei
2017-08-05  6:56 ` [PATCH V2 14/20] blk-mq-sched: improve IO scheduling on SCSI devcie Ming Lei
2017-08-22 20:51   ` Bart Van Assche
2017-08-24  7:14     ` Ming Lei
2017-08-05  6:57 ` [PATCH V2 15/20] block: introduce rqhash helpers Ming Lei
2017-08-05  6:57 ` [PATCH V2 16/20] block: move actual bio merge code into __elv_merge Ming Lei
2017-08-05  6:57 ` [PATCH V2 17/20] block: add check on elevator for supporting bio merge via hashtable from blk-mq sw queue Ming Lei
2017-08-05  6:57 ` [PATCH V2 18/20] block: introduce .last_merge and .hash to blk_mq_ctx Ming Lei
2017-08-05  6:57 ` [PATCH V2 19/20] blk-mq-sched: refactor blk_mq_sched_try_merge() Ming Lei
2017-08-05  6:57 ` [PATCH V2 20/20] blk-mq: improve bio merge from blk-mq sw queue Ming Lei
2017-08-07 12:48 ` [PATCH V2 00/20] blk-mq-sched: improve SCSI-MQ performance Laurence Oberman
2017-08-07 15:27   ` Bart Van Assche
2017-08-07 17:29     ` Laurence Oberman
2017-08-07 18:46       ` Laurence Oberman
2017-08-07 19:46         ` Laurence Oberman
2017-08-07 23:04       ` Ming Lei
     [not found]   ` <CAFfF4qv3W6D-j8BSSZbwPLqhd_mmwk8CZQe7dSqud8cMMd2yPg@mail.gmail.com>
2017-08-07 22:29     ` Bart Van Assche
2017-08-07 23:17     ` Ming Lei
2017-08-08 13:41     ` Ming Lei
2017-08-08 13:58       ` Laurence Oberman
2017-08-08  8:09 ` Paolo Valente
2017-08-08  9:09   ` Ming Lei
2017-08-08  9:13     ` Paolo Valente
2017-08-11  8:11 ` Christoph Hellwig
2017-08-11 14:25   ` James Bottomley [this message]
2017-08-23 16:12 ` Bart Van Assche
2017-08-23 16:15   ` Jens Axboe
2017-08-23 16:24     ` Ming Lei

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