From: snitzer@redhat.com (Mike Snitzer)
Subject: [RFC PATCH] dm: fix excessive dm-mq context switching
Date: Sun, 7 Feb 2016 12:20:56 -0500 [thread overview]
Message-ID: <20160207172055.GA6477@redhat.com> (raw)
In-Reply-To: <56B776DE.30101@dev.mellanox.co.il>
On Sun, Feb 07 2016 at 11:54am -0500,
Sagi Grimberg <sagig@dev.mellanox.co.il> wrote:
>
> >>If so, can you check with e.g.
> >>perf record -ags -e LLC-load-misses sleep 10 && perf report whether this
> >>workload triggers perhaps lock contention ? What you need to look for in
> >>the perf output is whether any functions occupy more than 10% CPU time.
> >
> >I will, thanks for the tip!
>
> The perf report is very similar to the one that started this effort..
>
> I'm afraid we'll need to resolve the per-target m->lock in order
> to scale with NUMA...
Could be. Just for testing, you can try the 2 topmost commits I've put
here (once applied both __multipath_map and multipath_busy won't have
_any_ locking.. again, very much test-only):
http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/log/?h=devel2
WARNING: multiple messages have this Message-ID (diff)
From: Mike Snitzer <snitzer@redhat.com>
To: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: "axboe@kernel.dk" <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"keith.busch@intel.com" <keith.busch@intel.com>,
device-mapper development <dm-devel@redhat.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Bart Van Assche <bart.vanassche@sandisk.com>
Subject: Re: [RFC PATCH] dm: fix excessive dm-mq context switching
Date: Sun, 7 Feb 2016 12:20:56 -0500 [thread overview]
Message-ID: <20160207172055.GA6477@redhat.com> (raw)
In-Reply-To: <56B776DE.30101@dev.mellanox.co.il>
On Sun, Feb 07 2016 at 11:54am -0500,
Sagi Grimberg <sagig@dev.mellanox.co.il> wrote:
>
> >>If so, can you check with e.g.
> >>perf record -ags -e LLC-load-misses sleep 10 && perf report whether this
> >>workload triggers perhaps lock contention ? What you need to look for in
> >>the perf output is whether any functions occupy more than 10% CPU time.
> >
> >I will, thanks for the tip!
>
> The perf report is very similar to the one that started this effort..
>
> I'm afraid we'll need to resolve the per-target m->lock in order
> to scale with NUMA...
Could be. Just for testing, you can try the 2 topmost commits I've put
here (once applied both __multipath_map and multipath_busy won't have
_any_ locking.. again, very much test-only):
http://git.kernel.org/cgit/linux/kernel/git/snitzer/linux.git/log/?h=devel2
next prev parent reply other threads:[~2016-02-07 17:20 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-18 12:04 dm-multipath low performance with blk-mq Sagi Grimberg
2016-01-19 10:37 ` Sagi Grimberg
2016-01-19 22:45 ` Mike Snitzer
2016-01-19 22:45 ` Mike Snitzer
2016-01-25 21:40 ` Mike Snitzer
2016-01-25 21:40 ` Mike Snitzer
2016-01-25 23:37 ` [dm-devel] " Benjamin Marzinski
2016-01-25 23:37 ` Benjamin Marzinski
2016-01-26 13:29 ` Mike Snitzer
2016-01-26 13:29 ` Mike Snitzer
2016-01-26 14:01 ` Hannes Reinecke
2016-01-26 14:47 ` Mike Snitzer
2016-01-26 14:47 ` Mike Snitzer
2016-01-26 14:56 ` Christoph Hellwig
2016-01-26 14:56 ` Christoph Hellwig
2016-01-26 15:27 ` Mike Snitzer
2016-01-26 15:27 ` Mike Snitzer
2016-01-26 15:57 ` Benjamin Marzinski
2016-01-27 11:14 ` Sagi Grimberg
2016-01-27 11:14 ` Sagi Grimberg
2016-01-27 17:48 ` Mike Snitzer
2016-01-27 17:48 ` Mike Snitzer
2016-01-27 17:51 ` Jens Axboe
2016-01-27 17:51 ` Jens Axboe
2016-01-27 18:16 ` Mike Snitzer
2016-01-27 18:16 ` Mike Snitzer
2016-01-27 18:26 ` Jens Axboe
2016-01-27 18:26 ` Jens Axboe
2016-01-27 19:14 ` Mike Snitzer
2016-01-27 19:14 ` Mike Snitzer
2016-01-27 19:50 ` Jens Axboe
2016-01-27 19:50 ` Jens Axboe
2016-01-27 17:56 ` Sagi Grimberg
2016-01-27 17:56 ` Sagi Grimberg
2016-01-27 18:42 ` Mike Snitzer
2016-01-27 18:42 ` Mike Snitzer
2016-01-27 19:49 ` Jens Axboe
2016-01-27 19:49 ` Jens Axboe
2016-01-27 20:45 ` Mike Snitzer
2016-01-27 20:45 ` Mike Snitzer
2016-01-29 23:35 ` Mike Snitzer
2016-01-29 23:35 ` Mike Snitzer
2016-01-30 8:52 ` Hannes Reinecke
2016-01-30 8:52 ` Hannes Reinecke
2016-01-30 19:12 ` Mike Snitzer
2016-01-30 19:12 ` Mike Snitzer
2016-02-01 6:46 ` Hannes Reinecke
2016-02-01 6:46 ` Hannes Reinecke
2016-02-03 18:04 ` Mike Snitzer
2016-02-03 18:04 ` Mike Snitzer
2016-02-03 18:24 ` Mike Snitzer
2016-02-03 18:24 ` Mike Snitzer
2016-02-03 19:22 ` Mike Snitzer
2016-02-03 19:22 ` Mike Snitzer
2016-02-04 6:54 ` Hannes Reinecke
2016-02-04 6:54 ` Hannes Reinecke
2016-02-04 13:54 ` Mike Snitzer
2016-02-04 13:54 ` Mike Snitzer
2016-02-04 13:58 ` Hannes Reinecke
2016-02-04 13:58 ` Hannes Reinecke
2016-02-04 14:09 ` Mike Snitzer
2016-02-04 14:09 ` Mike Snitzer
2016-02-04 14:32 ` Hannes Reinecke
2016-02-04 14:32 ` Hannes Reinecke
2016-02-04 14:44 ` Mike Snitzer
2016-02-04 14:44 ` Mike Snitzer
2016-02-05 15:13 ` [RFC PATCH] dm: fix excessive dm-mq context switching Mike Snitzer
2016-02-05 15:13 ` Mike Snitzer
2016-02-05 18:05 ` Mike Snitzer
2016-02-05 18:05 ` Mike Snitzer
2016-02-05 19:19 ` Mike Snitzer
2016-02-05 19:19 ` Mike Snitzer
2016-02-07 15:41 ` Sagi Grimberg
2016-02-07 15:41 ` Sagi Grimberg
2016-02-07 16:07 ` Mike Snitzer
2016-02-07 16:07 ` Mike Snitzer
2016-02-07 16:42 ` Sagi Grimberg
2016-02-07 16:42 ` Sagi Grimberg
2016-02-07 16:37 ` Bart Van Assche
2016-02-07 16:37 ` Bart Van Assche
2016-02-07 16:43 ` Sagi Grimberg
2016-02-07 16:43 ` Sagi Grimberg
2016-02-07 16:53 ` Mike Snitzer
2016-02-07 16:53 ` Mike Snitzer
2016-02-07 16:54 ` Sagi Grimberg
2016-02-07 16:54 ` Sagi Grimberg
2016-02-07 17:20 ` Mike Snitzer [this message]
2016-02-07 17:20 ` Mike Snitzer
2016-02-08 12:21 ` Sagi Grimberg
2016-02-08 12:21 ` Sagi Grimberg
2016-02-08 14:34 ` Mike Snitzer
2016-02-08 14:34 ` Mike Snitzer
2016-02-09 7:50 ` Hannes Reinecke
2016-02-09 7:50 ` Hannes Reinecke
2016-02-09 14:55 ` Mike Snitzer
2016-02-09 14:55 ` Mike Snitzer
2016-02-09 15:32 ` Hannes Reinecke
2016-02-09 15:32 ` Hannes Reinecke
2016-02-10 0:45 ` Mike Snitzer
2016-02-10 0:45 ` Mike Snitzer
2016-02-11 1:50 ` RCU-ified dm-mpath for testing/review Mike Snitzer
2016-02-11 3:35 ` Mike Snitzer
2016-02-11 3:35 ` Mike Snitzer
2016-02-11 15:34 ` Mike Snitzer
2016-02-11 15:34 ` Mike Snitzer
2016-02-12 15:18 ` Hannes Reinecke
2016-02-12 15:18 ` Hannes Reinecke
2016-02-12 15:26 ` Mike Snitzer
2016-02-12 15:26 ` Mike Snitzer
2016-02-12 16:04 ` Hannes Reinecke
2016-02-12 16:04 ` Hannes Reinecke
2016-02-12 18:00 ` Mike Snitzer
2016-02-12 18:00 ` Mike Snitzer
2016-02-15 6:47 ` Hannes Reinecke
2016-02-15 6:47 ` Hannes Reinecke
2016-01-26 1:49 ` [dm-devel] dm-multipath low performance with blk-mq Benjamin Marzinski
2016-01-26 1:49 ` Benjamin Marzinski
2016-01-26 16:03 ` Mike Snitzer
2016-01-26 16:03 ` Mike Snitzer
2016-01-26 16:44 ` Christoph Hellwig
2016-01-26 16:44 ` Christoph Hellwig
2016-01-27 2:09 ` Mike Snitzer
2016-01-27 2:09 ` Mike Snitzer
2016-01-27 11:10 ` Sagi Grimberg
2016-01-27 11:10 ` Sagi Grimberg
2016-01-26 21:40 ` [dm-devel] " Benjamin Marzinski
2016-01-26 21:40 ` Benjamin Marzinski
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