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From: Tejun Heo <tj@kernel.org>
To: Shaohua Li <shli@fb.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Kernel-team@fb.com, axboe@fb.com, vgoyal@redhat.com
Subject: Re: [PATCH V4 07/15] blk-throttle: make throtl_slice tunable
Date: Tue, 22 Nov 2016 16:27:15 -0500	[thread overview]
Message-ID: <20161122212715.GD17534@htj.duckdns.org> (raw)
In-Reply-To: <24137f881a149d30b98ef040367f26378128d4d2.1479161136.git.shli@fb.com>

Hello,

On Mon, Nov 14, 2016 at 02:22:14PM -0800, Shaohua Li wrote:
> throtl_slice is important for blk-throttling. A lot of stuffes depend on
> it, for example, throughput measurement. It has 100ms default value,
> which is not appropriate for all disks. For example, for SSD we might
> use a smaller value to make the throughput smoother. This patch makes it
> tunable.

It bothers me a bit because time slice doesn't mean anything inherent
to throttling.  It really is an implementation detail - throttling can
be implemented at per-operation level without time slice involved at
all.  It's okay to expose the knob if necessary but the meaning of the
knob is almost completely arbitrary to users (as it has no inherent
meaning).

Thanks.

-- 
tejun

  reply	other threads:[~2016-11-22 21:27 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-14 22:22 [PATCH V4 00/15] blk-throttle: add .high limit Shaohua Li
2016-11-14 22:22 ` [PATCH V4 01/15] blk-throttle: prepare support multiple limits Shaohua Li
2016-11-14 22:22 ` [PATCH V4 02/15] blk-throttle: add .high interface Shaohua Li
2016-11-22 20:02   ` Tejun Heo
2016-11-22 23:08     ` Shaohua Li
2016-11-23 21:11       ` Tejun Heo
2016-11-14 22:22 ` [PATCH V4 03/15] blk-throttle: configure bps/iops limit for cgroup in high limit Shaohua Li
2016-11-22 20:16   ` Tejun Heo
2016-11-22 23:11     ` Shaohua Li
2016-11-14 22:22 ` [PATCH V4 04/15] blk-throttle: add upgrade logic for LIMIT_HIGH state Shaohua Li
2016-11-14 22:22 ` [PATCH V4 05/15] blk-throttle: add downgrade logic Shaohua Li
2016-11-22 21:21   ` Tejun Heo
2016-11-22 21:42     ` Tejun Heo
2016-11-22 23:38       ` Shaohua Li
2016-11-14 22:22 ` [PATCH V4 06/15] blk-throttle: make sure expire time isn't too big Shaohua Li
2016-11-14 22:22 ` [PATCH V4 07/15] blk-throttle: make throtl_slice tunable Shaohua Li
2016-11-22 21:27   ` Tejun Heo [this message]
2016-11-22 23:18     ` Shaohua Li
2016-11-23 21:17       ` Tejun Heo
2016-11-14 22:22 ` [PATCH V4 08/15] blk-throttle: detect completed idle cgroup Shaohua Li
2016-11-14 22:22 ` [PATCH V4 09/15] blk-throttle: make bandwidth change smooth Shaohua Li
2016-11-23 21:23   ` Tejun Heo
2016-11-24  0:59     ` Shaohua Li
2016-11-14 22:22 ` [PATCH V4 10/15] blk-throttle: add a simple idle detection Shaohua Li
2016-11-23 21:46   ` Tejun Heo
2016-11-24  1:15     ` Shaohua Li
2016-11-28 22:21       ` Tejun Heo
2016-11-28 23:10         ` Shaohua Li
2016-11-29 17:08           ` Tejun Heo
2016-11-14 22:22 ` [PATCH V4 11/15] blk-throttle: add interface to configure think time threshold Shaohua Li
2016-11-23 21:32   ` Tejun Heo
2016-11-24  1:06     ` Shaohua Li
2016-11-28 22:08       ` Tejun Heo
2016-11-28 22:14         ` Shaohua Li
2016-11-14 22:22 ` [PATCH V4 12/15] blk-throttle: ignore idle cgroup limit Shaohua Li
2016-11-14 22:22 ` [PATCH V4 13/15] blk-throttle: add a mechanism to estimate IO latency Shaohua Li
2016-11-14 23:40   ` kbuild test robot
2016-11-15  3:57   ` kbuild test robot
2016-11-29 17:24   ` Tejun Heo
2016-11-29 18:30     ` Shaohua Li
2016-11-29 22:36       ` Tejun Heo
2016-11-14 22:22 ` [PATCH V4 14/15] blk-throttle: add interface for per-cgroup target latency Shaohua Li
2016-11-14 22:22 ` [PATCH V4 15/15] blk-throttle: add latency target support Shaohua Li
2016-11-29 17:31   ` Tejun Heo
2016-11-29 18:14     ` Shaohua Li
2016-11-29 22:54       ` Tejun Heo
2016-11-29 23:39         ` Shaohua Li
2016-11-14 22:46 ` [PATCH V4 00/15] blk-throttle: add .high limit Bart Van Assche
2016-11-15  0:05   ` Shaohua Li
2016-11-15  0:41     ` Bart Van Assche
2016-11-15  0:49       ` Shaohua Li
2016-11-15  1:18         ` Bart Van Assche
2016-11-15  1:28           ` Shaohua Li
2016-11-15 19:53             ` Bart Van Assche
2016-11-15 21:31               ` Shaohua Li

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