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From: Tejun Heo <tj@kernel.org>
To: Paolo Valente <paolo.valente@unimore.it>
Cc: Vivek Goyal <vgoyal@redhat.com>, Shaohua Li <shli@fb.com>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jens Axboe <axboe@fb.com>,
	Kernel-team@fb.com, jmoyer@redhat.com,
	Mark Brown <broonie@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Ulf Hansson <ulf.hansson@linaro.org>
Subject: Re: [PATCH V3 00/11] block-throttle: add .high limit
Date: Tue, 4 Oct 2016 12:27:59 -0400	[thread overview]
Message-ID: <20161004162759.GD4205@htj.duckdns.org> (raw)
In-Reply-To: <A5525664-DF90-4604-B64A-E793BBC0CB6A@unimore.it>

Hello,

On Tue, Oct 04, 2016 at 06:22:28PM +0200, Paolo Valente wrote:
> Could you please elaborate more on this point?  BFQ uses sectors
> served to measure service, and, on the all the fast devices on which
> we have tested it, it accurately distributes
> bandwidth as desired, redistributes excess bandwidth with any issue,
> and guarantees high responsiveness and low latency at application and
> system level (e.g., ~0 drop rate in video playback, with any background
> workload tested).

The same argument as before.  Bandwidth is a very bad measure of IO
resources spent.  For specific use cases (like desktop or whatever),
this can work but not generally.

> Could you please suggest me some test to show how sector-based
> guarantees fails?

Well, mix 4k random and sequential workloads and try to distribute the
acteual IO resources.

Thanks.

-- 
tejun

  reply	other threads:[~2016-10-04 16:28 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-03 21:20 [PATCH V3 00/11] block-throttle: add .high limit Shaohua Li
2016-10-03 21:20 ` [PATCH v3 01/11] block-throttle: prepare support multiple limits Shaohua Li
2016-10-03 21:20 ` [PATCH v3 02/11] block-throttle: add .high interface Shaohua Li
2016-10-03 21:20 ` [PATCH v3 03/11] block-throttle: configure bps/iops limit for cgroup in high limit Shaohua Li
2016-10-03 21:20 ` [PATCH v3 04/11] block-throttle: add upgrade logic for LIMIT_HIGH state Shaohua Li
2016-10-03 21:20 ` [PATCH v3 05/11] block-throttle: add downgrade logic Shaohua Li
2016-10-03 21:20 ` [PATCH v3 06/11] blk-throttle: make sure expire time isn't too big Shaohua Li
2016-10-03 21:20 ` [PATCH v3 07/11] blk-throttle: make throtl_slice tunable Shaohua Li
2016-10-03 21:20 ` [PATCH v3 08/11] blk-throttle: detect completed idle cgroup Shaohua Li
2016-10-03 21:20 ` [PATCH v3 09/11] block-throttle: make bandwidth change smooth Shaohua Li
2016-10-03 21:20 ` [PATCH v3 10/11] block-throttle: add a simple idle detection Shaohua Li
2016-10-03 21:20 ` [PATCH v3 11/11] blk-throttle: ignore idle cgroup limit Shaohua Li
2016-10-04 13:28 ` [PATCH V3 00/11] block-throttle: add .high limit Vivek Goyal
2016-10-04 15:56   ` Tejun Heo
2016-10-04 16:22     ` Paolo Valente
2016-10-04 16:27       ` Tejun Heo [this message]
2016-10-04 17:01         ` Paolo Valente
2016-10-04 17:28           ` Shaohua Li
2016-10-04 17:43             ` Paolo Valente
2016-10-04 18:28               ` Shaohua Li
2016-10-04 19:49                 ` Paolo Valente
2016-10-04 18:54               ` Tejun Heo
2016-10-04 19:02                 ` Paolo Valente
2016-10-04 19:14                   ` Tejun Heo
2016-10-04 19:29                     ` Paolo Valente
2016-10-04 20:27                       ` Tejun Heo
2016-10-05 12:37                         ` Paolo Valente
2016-10-05 13:12                           ` Vivek Goyal
2016-10-05 14:04                             ` Paolo Valente
2016-10-05 14:49                           ` Tejun Heo
2016-10-05 18:30                             ` Shaohua Li
2016-10-05 19:08                               ` Shaohua Li
2016-10-05 19:57                                 ` Paolo Valente
2016-10-05 20:36                                   ` Shaohua Li
2016-10-06  7:22                                     ` Paolo Valente
2016-10-05 19:47                               ` Paolo Valente
2016-10-05 20:07                                 ` Paolo Valente
2016-10-05 20:46                                 ` Shaohua Li
2016-10-06  7:58                                   ` Paolo Valente
2016-10-06 13:15                                     ` Paolo Valente
2016-10-06 17:49                                       ` Vivek Goyal
2016-10-06 18:01                                         ` Paolo Valente
2016-10-06 18:32                                           ` Vivek Goyal
2016-10-06 20:51                                             ` Paolo Valente
2016-10-06 19:44                                         ` Mark Brown
2016-10-06 19:57                                     ` Shaohua Li
2016-10-06 22:24                                       ` Paolo Valente
     [not found]                         ` <CACsaVZ+AqSXHTRdpdrQQp6PuynEPeB-5YOyweWsenjvuKsD12w@mail.gmail.com>
2016-10-09  1:15                           ` Fwd: " Kyle Sanderson
2016-10-14 16:40                             ` Tejun Heo
2016-10-14 17:13                               ` Paolo Valente
2016-10-14 18:35                                 ` Tejun Heo
2016-10-16 19:02                                   ` Paolo Valente
2016-10-18  5:15                                     ` Kyle Sanderson
2016-10-06  8:04                     ` Linus Walleij
2016-10-06 11:03                       ` Mark Brown
2016-10-06 11:57                         ` Austin S. Hemmelgarn
2016-10-06 12:50                           ` Paolo Valente
2016-10-06 13:52                             ` Austin S. Hemmelgarn
2016-10-06 15:05                               ` Paolo Valente
2016-10-06 15:10                                 ` Austin S. Hemmelgarn
2016-10-08 10:46                       ` Heinz Diehl
2016-10-04 18:12     ` Vivek Goyal
2016-10-04 18:50       ` Tejun Heo
2016-10-04 18:56         ` Paolo Valente
2016-10-04 17:08   ` Shaohua Li

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