From: Shaohua Li <shli@fb.com>
To: Tejun Heo <tj@kernel.org>
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 15:18:24 -0800 [thread overview]
Message-ID: <20161122231824.GC14628@shli-mbp.local> (raw)
In-Reply-To: <20161122212715.GD17534@htj.duckdns.org>
On Tue, Nov 22, 2016 at 04:27:15PM -0500, Tejun Heo wrote:
> 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).
Hmm, it's not a real 'time slice'. The name is a bit confusion. Maybe rename it
to 'throtl_interval' or 'throtl_sampling_time'? not sure. bandwidth and iops
are always in terms of a time interval we measure them. We can't say the
iops/bw for a single io. So this is really a tuable knob.
Thanks,
Shaohua
next prev parent reply other threads:[~2016-11-22 23:18 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
2016-11-22 23:18 ` Shaohua Li [this message]
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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