Re: [dm-devel] [PATCH V5 00/14] blk-mq-sched: improve sequential I/O performance(part 1)

On Mon, Oct 09, 2017 at 11:04:39PM +0800, Ming Lei wrote: > Hi John, > > On Mon, Oct 09, 2017 at 01:09:22PM +0100, John Garry wrote: > > On 30/09/2017 11:27, Ming Lei wrote: > > > Hi Jens, > > > > > > In Red Hat internal storage test wrt. blk-mq scheduler, we > > > found that I/O performance is

Re: [dm-devel] [PATCH v4 1/6] libmultipath: add detect_checker option

On Mon, 2017-10-09 at 14:09 -0500, Benjamin Marzinski wrote: > On Thu, Oct 05, 2017 at 10:25:50PM +0200, Martin Wilck wrote: > > > > Like this, perhaps? > > > > Martin Wilck (1): > > limbultipath: prefer RDAC checker with detect_checker > > Oops. I totally dropped this off my plate. But, yes,

Re: [dm-devel] [PATCH v4 1/6] libmultipath: add detect_checker option

On Thu, Oct 05, 2017 at 10:25:50PM +0200, Martin Wilck wrote: > On Mon, 2017-09-25 at 11:49 -0500, Benjamin Marzinski wrote: > > On Mon, Sep 25, 2017 at 06:15:20PM +0200, Xose Vazquez Perez wrote: > > > On 02/27/2017 07:26 PM, Benjamin Marzinski wrote: > > > > > > > This patch adds a

Re: [dm-devel] [PATCH V5 00/14] blk-mq-sched: improve sequential I/O performance(part 1)

Hi John, On Mon, Oct 09, 2017 at 01:09:22PM +0100, John Garry wrote: > On 30/09/2017 11:27, Ming Lei wrote: > > Hi Jens, > > > > In Red Hat internal storage test wrt. blk-mq scheduler, we > > found that I/O performance is much bad with mq-deadline, especially > > about sequential I/O on some

Re: [dm-devel] [PATCH V5 00/14] blk-mq-sched: improve sequential I/O performance(part 1)

On 30/09/2017 11:27, Ming Lei wrote: Hi Jens, In Red Hat internal storage test wrt. blk-mq scheduler, we found that I/O performance is much bad with mq-deadline, especially about sequential I/O on some multi-queue SCSI devcies(lpfc, qla2xxx, SRP...) Turns out one big issue causes the

[dm-devel] [PATCH V6 5/5] blk-mq-sched: don't dequeue request until all in ->dispatch are flushed

During dispatching, we moved all requests from hctx->dispatch to one temporary list, then dispatch them one by one from this list. Unfortunately during this period, run queue from other contexts may think the queue is idle, then start to dequeue from sw/scheduler queue and still try to dispatch

Re: [dm-devel] [PATCH V4 1/2] multipath-tools: intermittent IO error accounting to improve reliability

Hi Guan, Thanks for the info. Changes looks fine. Instead of marginal_path_err_recheck_gap_time, marginal_path_recovery_time will looks reasonable. This was only my input. Regards, Muneendra. -Original Message- From: Guan Junxiong [mailto:guanjunxi...@huawei.com] Sent: Monday, October

[dm-devel] [PATCH V6 2/5] blk-mq-sched: move actual dispatching into one helper

So that it becomes easy to support to dispatch from sw queue in the following patch. No functional change. Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval Suggested-by: Christoph Hellwig # for simplifying dispatch logic

[dm-devel] [PATCH V6 3/5] sbitmap: introduce __sbitmap_for_each_set()

We need to iterate ctx starting from any ctx in round robin way, so introduce this helper. Cc: Omar Sandoval Signed-off-by: Ming Lei --- include/linux/sbitmap.h | 64 - 1 file changed, 47 insertions(+), 17

[dm-devel] [PATCH V6 1/5] blk-mq-sched: fix scheduler bad performance

When hw queue is busy, we shouldn't take requests from scheduler queue any more, otherwise it is difficult to do IO merge. This patch fixes the awful IO performance on some SCSI devices(lpfc, qla2xxx, ...) when mq-deadline/kyber is used by not taking requests if hw queue is busy. Reviewed-by:

[dm-devel] [PATCH V6 4/5] blk-mq-sched: improve dispatching from sw queue

SCSI devices use host-wide tagset, and the shared driver tag space is often quite big. Meantime there is also queue depth for each lun( .cmd_per_lun), which is often small, for example, on both lpfc and qla2xxx, .cmd_per_lun is just 3. So lots of requests may stay in sw queue, and we always flush

[dm-devel] [PATCH V6 0/5] blk-mq-sched: improve sequential I/O performance

Hi Jens, In Red Hat internal storage test wrt. blk-mq scheduler, we found that I/O performance is much bad with mq-deadline, especially about sequential I/O on some multi-queue SCSI devcies(lpfc, qla2xxx, SRP...) Turns out one big issue causes the performance regression: requests are still

Re: [dm-devel] [PATCH V5 7/7] blk-mq-sched: don't dequeue request until all in ->dispatch are flushed

On Tue, Oct 03, 2017 at 02:11:28AM -0700, Christoph Hellwig wrote: > This looks good in general: > > Reviewed-by: Christoph Hellwig > > Minor nitpicks below: > > > const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; > > This is now only tested once, so you

Re: [dm-devel] [PATCH V5 6/7] blk-mq-sched: improve dispatching from sw queue

On Tue, Oct 03, 2017 at 02:05:27AM -0700, Christoph Hellwig wrote: > On Sat, Sep 30, 2017 at 06:27:19PM +0800, Ming Lei wrote: > > SCSI devices use host-wide tagset, and the shared > > driver tag space is often quite big. Meantime > > there is also queue depth for each lun(.cmd_per_lun), > > which

Re: [dm-devel] [PATCH V5 5/7] blk-mq-sched: move actual dispatching into one helper

On Mon, Oct 02, 2017 at 07:19:56AM -0700, Christoph Hellwig wrote: > Can you move this to the beginning of your series, just after > the other edits to blk_mq_sched_dispatch_requests? OK. > > > +static void blk_mq_do_dispatch_sched(struct request_queue *q, > > +

Re: [dm-devel] [PATCH 1/1] limbultipath: prefer RDAC checker with detect_checker

> From: dm-devel-boun...@redhat.com [mailto:dm-devel-boun...@redhat.com] On > Behalf Of Martin Wilck > Sent: Thursday, October 05, 2017 3:26 PM > To: Benjamin Marzinski > Cc: Martin Wilck ; dm-devel@redhat.com; Xose Vazquez Perez > >