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From: Bart Van Assche <bvanassche@acm.org>
To: Jens Axboe <axboe@kernel.dk>,
	Zhen Lei <thunder.leizhen@huawei.com>,
	linux-block <linux-block@vger.kernel.org>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Subject: Re: [PATCH] block/mq-deadline: Speed up the dispatch of low-priority requests
Date: Thu, 26 Aug 2021 17:03:21 -0700	[thread overview]
Message-ID: <2332cba0-efe6-3b35-0587-ee6355a3567d@acm.org> (raw)
In-Reply-To: <0ef7865d-a9ce-c5d9-ff7f-c0ef58de3d21@kernel.dk>

On 8/26/21 4:51 PM, Jens Axboe wrote:
> On 8/26/21 5:49 PM, Bart Van Assche wrote:
>> On 8/26/21 11:45 AM, Jens Axboe wrote:
>>> Just ran a quick test here, and I go from 3.55M IOPS to 1.23M switching
>>> to deadline, of which 37% of the overhead is from dd_dispatch().
>>>
>>> With the posted patch applied, it runs at 2.3M IOPS with mq-deadline,
>>> which is a lot better. This is on my 3970X test box, so 32 cores, 64
>>> threads.
>>
>> Hi Jens,
>>
>> With the script below, queue depth >= 2 and an improved version of
>> Zhen's patch I see 970 K IOPS with the mq-deadline scheduler in an
>> 8 core VM (i7-4790 CPU). In other words, more IOPS than what Zhen
>> reported with fewer CPU cores. Is that good enough?
> 
> That depends, what kind of IOPS are you getting if you revert the
> original change?

Hi Jens,

Here is an overview of the tests I ran so far, all on the same test
setup:
* No I/O scheduler:               about 5630 K IOPS.
* Kernel v5.11 + mq-deadline:     about 1100 K IOPS.
* block-for-next + mq-deadline:   about  760 K IOPS.
* block-for-next with improved mq-deadline performance: about 970 K IOPS.

Bart.



  reply	other threads:[~2021-08-27  0:03 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-26 14:40 [PATCH] block/mq-deadline: Speed up the dispatch of low-priority requests Zhen Lei
2021-08-26 18:09 ` Bart Van Assche
2021-08-26 18:13   ` Jens Axboe
2021-08-26 18:45     ` Jens Axboe
2021-08-26 19:17       ` Bart Van Assche
2021-08-26 19:32         ` Jens Axboe
2021-08-26 23:49       ` Bart Van Assche
2021-08-26 23:51         ` Jens Axboe
2021-08-27  0:03           ` Bart Van Assche [this message]
2021-08-27  0:05             ` Jens Axboe
2021-08-27  0:58               ` Bart Van Assche
2021-08-27  2:48               ` Bart Van Assche
2021-08-27  3:13                 ` Jens Axboe
2021-08-27  4:49                   ` Damien Le Moal
2021-08-27 14:34                     ` Bart Van Assche
2021-08-29 23:02                       ` Damien Le Moal
2021-08-30  2:31                         ` Keith Busch
2021-08-30  3:03                           ` Damien Le Moal
2021-08-30  2:40                         ` Bart Van Assche
2021-08-30  3:07                           ` Damien Le Moal
2021-08-30 17:14                             ` Bart Van Assche
2021-08-30 21:42                               ` Damien Le Moal
2021-08-28  1:45                   ` Leizhen (ThunderTown)
2021-08-28  2:19                     ` Bart Van Assche
2021-08-28  2:42                       ` Leizhen (ThunderTown)
2021-08-28 13:14                         ` Leizhen (ThunderTown)
2021-08-28  1:59   ` Leizhen (ThunderTown)
2021-08-28  2:41     ` Bart Van Assche
2021-08-27  2:30 ` Damien Le Moal
2021-08-28  2:14   ` Leizhen (ThunderTown)

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