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From: Tejun Heo <tj@kernel.org>
To: Nikolay Borisov <nborisov@suse.com>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com,
	peterz@infradead.org, kernel-team@fb.com, osandov@fb.com
Subject: Re: [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED
Date: Tue, 12 Dec 2017 09:29:08 -0800	[thread overview]
Message-ID: <20171212172908.GG3919388@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <8bf8dcc8-6198-902b-5c4c-7c66c17c9fd0@suse.com>

Hello, Nikolay.

On Tue, Dec 12, 2017 at 01:17:52PM +0200, Nikolay Borisov wrote:
> On  9.12.2017 21:25, Tejun Heo wrote:
> > After the recent updates to use generation number and state based
> > synchronization, we can easily replace REQ_ATOM_STARTED usages by
> > adding an extra state to distinguish completed but not yet freed
> > state.
> > 
> > Add MQ_RQ_COMPLETE and replace REQ_ATOM_STARTED usages with
> > blk_mq_rq_state() tests.  REQ_ATOM_STARTED no longer has any users
> > left and is removed.
> 
> Where are the promised in patch 5/6 performance results?

Opos, I thought I removed all of those.  I couldn't reliably show that
this performed better.  I was testing with nullblk but the run-to-run
deviations were too great (they generally kept getting faster, maybe
better locality?) to draw a reliable conclusion.  Whatever difference
in performance is unlikely to be material in actual workloads anyway.

I dropped the sentence from the description.

Thanks.

-- 
tejun

  reply	other threads:[~2017-12-12 17:29 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-09 19:25 [PATCHSET] blk-mq: reimplement timeout handling Tejun Heo
2017-12-09 19:25 ` [PATCH 1/6] blk-mq: protect completion path with RCU Tejun Heo
2017-12-13  3:10   ` jianchao.wang
2017-12-09 19:25 ` [PATCH 2/6] blk-mq: replace timeout synchronization with a RCU and generation based scheme Tejun Heo
2017-12-12 10:09   ` Peter Zijlstra
2017-12-12 18:02     ` Tejun Heo
2017-12-12 10:10   ` Peter Zijlstra
2017-12-12 18:03     ` Tejun Heo
2017-12-12 11:56   ` Peter Zijlstra
2017-12-12 18:04     ` Tejun Heo
2017-12-09 19:25 ` [PATCH 3/6] blk-mq: use blk_mq_rq_state() instead of testing REQ_ATOM_COMPLETE Tejun Heo
2017-12-09 19:25 ` [PATCH 4/6] blk-mq: make blk_abort_request() trigger timeout path Tejun Heo
2017-12-09 19:25 ` [PATCH 5/6] blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq Tejun Heo
2017-12-09 19:25 ` [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED Tejun Heo
2017-12-12 10:09   ` jianchao.wang
2017-12-12 17:01     ` Tejun Heo
2017-12-12 17:26     ` Tejun Heo
2017-12-13  3:05       ` jianchao.wang
2017-12-13 16:09         ` Tejun Heo
2017-12-14  2:14           ` jianchao.wang
2017-12-12 11:17   ` Nikolay Borisov
2017-12-12 17:29     ` Tejun Heo [this message]
2017-12-11  9:27 ` [PATCHSET] blk-mq: reimplement timeout handling Peter Zijlstra
2017-12-12  9:21 ` Christoph Hellwig
2017-12-12 16:39   ` Tejun Heo
2017-12-12 16:08 ` Peter Zijlstra
2017-12-12 19:01 [PATCHSET v2] " Tejun Heo
2017-12-12 19:01 ` [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED Tejun Heo
2017-12-12 22:20   ` Bart Van Assche
2017-12-12 22:22     ` tj

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