From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@infradead.org>, Arnd Bergmann <arnd@arndb.de>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>,
Jan Kara <jack@suse.cz>, Paolo Valente <paolo.valente@linaro.org>,
Tejun Heo <tj@kernel.org>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ulf.hansson@linaro.org, linus.walleij@linaro.org,
broonie@kernel.org, hare@suse.de, grant.likely@secretlab.ca,
James.Bottomley@hansenpartnership.com
Subject: Re: [PATCH 00/14] introduce the BFQ-v0 I/O scheduler as an extra scheduler
Date: Wed, 26 Oct 2016 09:32:36 -0600 [thread overview]
Message-ID: <3ebadbb8-9ac2-851a-66f9-c9db25713695@kernel.dk> (raw)
In-Reply-To: <20161026152955.GA21262@infradead.org>
On 10/26/2016 09:29 AM, Christoph Hellwig wrote:
> On Wed, Oct 26, 2016 at 05:13:07PM +0200, Arnd Bergmann wrote:
>> The question to ask first is whether to actually have pluggable
>> schedulers on blk-mq at all, or just have one that is meant to
>> do the right thing in every case (and possibly can be bypassed
>> completely).
>
> That would be my preference. Have a BFQ-variant for blk-mq as an
> option (default to off unless opted in by the driver or user), and
> not other scheduler for blk-mq. Don't bother with bfq for non
> blk-mq. It's not like there is any advantage in the legacy-request
> device even for slow devices, except for the option of having I/O
> scheduling.
It's the only right way forward. blk-mq might not offer any substantial
advantages to rotating storage, but with scheduling, it won't offer a
downside either. And it'll take us towards the real goal, which is to
have just one IO path. Adding a new scheduler for the legacy IO path
makes no sense. Adding one for blk-mq and phasing out the old path is
what we need to do.
--
Jens Axboe
next prev parent reply other threads:[~2016-10-26 15:32 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-26 9:27 Paolo Valente
2016-10-26 9:27 ` [PATCH 01/14] block, bfq: " Paolo Valente
2016-10-26 9:27 ` [PATCH 02/14] block, bfq: add full hierarchical scheduling and cgroups support Paolo Valente
2016-10-26 9:27 ` [PATCH 03/14] block, bfq: improve throughput boosting Paolo Valente
2016-10-26 9:27 ` [PATCH 04/14] block, bfq: modify the peak-rate estimator Paolo Valente
2016-10-26 9:27 ` [PATCH 05/14] block, bfq: add more fairness with writes and slow processes Paolo Valente
2016-10-26 9:27 ` [PATCH 06/14] block, bfq: improve responsiveness Paolo Valente
2016-10-26 9:28 ` [PATCH 07/14] block, bfq: reduce I/O latency for soft real-time applications Paolo Valente
2016-10-26 9:28 ` [PATCH 08/14] block, bfq: preserve a low latency also with NCQ-capable drives Paolo Valente
2016-10-26 9:28 ` [PATCH 09/14] block, bfq: reduce latency during request-pool saturation Paolo Valente
2016-10-26 10:19 ` [PATCH 00/14] introduce the BFQ-v0 I/O scheduler as an extra scheduler Christoph Hellwig
2016-10-26 11:34 ` Jan Kara
2016-10-26 15:05 ` Bart Van Assche
2016-10-26 15:13 ` Arnd Bergmann
2016-10-26 15:29 ` Christoph Hellwig
2016-10-26 15:32 ` Jens Axboe [this message]
2016-10-26 16:04 ` Paolo Valente
2016-10-26 16:12 ` Jens Axboe
2016-10-27 9:26 ` Jan Kara
2016-10-27 14:34 ` Grozdan
2016-10-27 15:55 ` Heinz Diehl
2016-10-27 16:28 ` Jens Axboe
2016-10-27 16:26 ` Jens Axboe
2016-10-28 7:59 ` Jan Kara
2016-10-28 14:10 ` Jens Axboe
2016-10-27 17:32 ` Ulf Hansson
2016-10-27 17:43 ` Jens Axboe
2016-10-27 18:13 ` Ulf Hansson
2016-10-27 18:21 ` Jens Axboe
2016-10-27 19:34 ` Ulf Hansson
2016-10-27 21:08 ` Jens Axboe
2016-10-27 22:27 ` Linus Walleij
2016-10-28 9:32 ` Linus Walleij
2016-10-28 14:22 ` Jens Axboe
2016-10-28 20:38 ` Linus Walleij
2016-10-28 15:29 ` Christoph Hellwig
2016-10-28 21:09 ` Linus Walleij
2016-10-28 15:30 ` Jens Axboe
2016-10-28 15:58 ` Bartlomiej Zolnierkiewicz
2016-10-28 16:05 ` Arnd Bergmann
2016-10-28 17:17 ` Mark Brown
2016-10-28 14:07 ` Jens Axboe
2016-10-28 6:36 ` Ulf Hansson
2016-10-28 14:17 ` Jens Axboe
2016-10-28 17:12 ` Mark Brown
2016-10-27 19:41 ` Mark Brown
2016-10-27 19:45 ` Christoph Hellwig
2016-10-27 22:01 ` Mark Brown
2016-10-28 12:07 ` Arnd Bergmann
2016-10-28 12:17 ` Richard Weinberger
2016-10-29 5:38 ` Paolo Valente
2016-10-29 13:12 ` Bart Van Assche
2016-10-29 14:12 ` Jens Axboe
2016-10-30 3:06 ` Paolo Valente
2016-10-26 12:37 ` Paolo Valente
2016-10-29 17:08 Manuel Krause
2016-10-30 17:48 Manuel Krause
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