From: Sagi Grimberg <sagig@dev.mellanox.co.il>
To: Bart Van Assche <bart.vanassche@sandisk.com>,
Mike Snitzer <snitzer@redhat.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
Hannes Reinecke <hare@suse.de>,
Christoph Hellwig <hch@infradead.org>
Cc: "keith.busch@intel.com" <keith.busch@intel.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
device-mapper development <dm-devel@redhat.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [RFC PATCH] dm: fix excessive dm-mq context switching
Date: Sun, 7 Feb 2016 18:54:54 +0200 [thread overview]
Message-ID: <56B776DE.30101@dev.mellanox.co.il> (raw)
In-Reply-To: <56B77444.3030106@dev.mellanox.co.il>
>> 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...
- 17.33% fio [kernel.kallsyms] [k]
queued_spin_lock_slowpath
- queued_spin_lock_slowpath
- 52.09% _raw_spin_lock_irq
__multipath_map
multipath_clone_and_map
map_request
dm_mq_queue_rq
__blk_mq_run_hw_queue
blk_mq_run_hw_queue
blk_mq_insert_requests
blk_mq_flush_plug_list
blk_flush_plug_list
blk_finish_plug
do_io_submit
SyS_io_submit
entry_SYSCALL_64_fastpath
+ io_submit
- 46.87% _raw_spin_lock_irqsave
- 99.97% multipath_busy
dm_mq_queue_rq
__blk_mq_run_hw_queue
blk_mq_run_hw_queue
blk_mq_insert_requests
blk_mq_flush_plug_list
blk_flush_plug_list
blk_finish_plug
do_io_submit
SyS_io_submit
entry_SYSCALL_64_fastpath
+ io_submit
+ 4.99% fio [kernel.kallsyms] [k]
blk_account_io_start
+ 3.93% fio [dm_multipath] [k] __multipath_map
+ 2.64% fio [dm_multipath] [k] multipath_busy
+ 2.38% fio [kernel.kallsyms] [k]
_raw_spin_lock_irqsave
+ 2.31% fio [dm_mod] [k] dm_mq_queue_rq
+ 2.25% fio [kernel.kallsyms] [k]
blk_mq_hctx_mark_pending
+ 1.81% fio [kernel.kallsyms] [k] blk_queue_enter
+ 1.61% perf [kernel.kallsyms] [k]
copy_user_generic_string
+ 1.40% fio [kernel.kallsyms] [k]
__blk_mq_run_hw_queue
+ 1.26% fio [kernel.kallsyms] [k] part_round_stats
+ 1.14% fio [kernel.kallsyms] [k] _raw_spin_lock_irq
+ 0.96% fio [kernel.kallsyms] [k] __bt_get
+ 0.73% fio [kernel.kallsyms] [k] enqueue_task_fair
+ 0.71% fio [kernel.kallsyms] [k] enqueue_entity
+ 0.69% fio [dm_mod] [k] dm_start_request
+ 0.60% ksoftirqd/6 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.59% ksoftirqd/10 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.59% fio [kernel.kallsyms] [k]
_raw_spin_unlock_irqrestore
+ 0.58% ksoftirqd/19 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.58% ksoftirqd/18 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.58% ksoftirqd/23 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
WARNING: multiple messages have this Message-ID (diff)
From: sagig@dev.mellanox.co.il (Sagi Grimberg)
Subject: [RFC PATCH] dm: fix excessive dm-mq context switching
Date: Sun, 7 Feb 2016 18:54:54 +0200 [thread overview]
Message-ID: <56B776DE.30101@dev.mellanox.co.il> (raw)
In-Reply-To: <56B77444.3030106@dev.mellanox.co.il>
>> 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...
- 17.33% fio [kernel.kallsyms] [k]
queued_spin_lock_slowpath
- queued_spin_lock_slowpath
- 52.09% _raw_spin_lock_irq
__multipath_map
multipath_clone_and_map
map_request
dm_mq_queue_rq
__blk_mq_run_hw_queue
blk_mq_run_hw_queue
blk_mq_insert_requests
blk_mq_flush_plug_list
blk_flush_plug_list
blk_finish_plug
do_io_submit
SyS_io_submit
entry_SYSCALL_64_fastpath
+ io_submit
- 46.87% _raw_spin_lock_irqsave
- 99.97% multipath_busy
dm_mq_queue_rq
__blk_mq_run_hw_queue
blk_mq_run_hw_queue
blk_mq_insert_requests
blk_mq_flush_plug_list
blk_flush_plug_list
blk_finish_plug
do_io_submit
SyS_io_submit
entry_SYSCALL_64_fastpath
+ io_submit
+ 4.99% fio [kernel.kallsyms] [k]
blk_account_io_start
+ 3.93% fio [dm_multipath] [k] __multipath_map
+ 2.64% fio [dm_multipath] [k] multipath_busy
+ 2.38% fio [kernel.kallsyms] [k]
_raw_spin_lock_irqsave
+ 2.31% fio [dm_mod] [k] dm_mq_queue_rq
+ 2.25% fio [kernel.kallsyms] [k]
blk_mq_hctx_mark_pending
+ 1.81% fio [kernel.kallsyms] [k] blk_queue_enter
+ 1.61% perf [kernel.kallsyms] [k]
copy_user_generic_string
+ 1.40% fio [kernel.kallsyms] [k]
__blk_mq_run_hw_queue
+ 1.26% fio [kernel.kallsyms] [k] part_round_stats
+ 1.14% fio [kernel.kallsyms] [k] _raw_spin_lock_irq
+ 0.96% fio [kernel.kallsyms] [k] __bt_get
+ 0.73% fio [kernel.kallsyms] [k] enqueue_task_fair
+ 0.71% fio [kernel.kallsyms] [k] enqueue_entity
+ 0.69% fio [dm_mod] [k] dm_start_request
+ 0.60% ksoftirqd/6 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.59% ksoftirqd/10 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.59% fio [kernel.kallsyms] [k]
_raw_spin_unlock_irqrestore
+ 0.58% ksoftirqd/19 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.58% ksoftirqd/18 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
+ 0.58% ksoftirqd/23 [kernel.kallsyms] [k]
blk_mq_run_hw_queues
next prev parent reply other threads:[~2016-02-07 16:54 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 ` Benjamin Marzinski
2016-01-25 23:37 ` [dm-devel] " 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 [this message]
2016-02-07 16:54 ` Sagi Grimberg
2016-02-07 17:20 ` Mike Snitzer
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-multipath low performance with blk-mq Benjamin Marzinski
2016-01-26 1:49 ` [dm-devel] " 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 ` Benjamin Marzinski
2016-01-26 21:40 ` [dm-devel] " Benjamin Marzinski
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