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From: Bart Van Assche <bvanassche@acm.org>
To: Yu Kuai <yukuai3@huawei.com>, axboe@kernel.dk, ming.lei@redhat.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	yi.zhang@huawei.com
Subject: Re: [PATCH] blk-mq: allow hardware queue to get more tag while sharing a tag set
Date: Sat, 31 Jul 2021 10:15:14 -0700	[thread overview]
Message-ID: <ade72519-5e16-1cc5-9a77-cb9ead42035e@acm.org> (raw)
In-Reply-To: <20210712031818.31918-1-yukuai3@huawei.com>

On 7/11/21 8:18 PM, Yu Kuai wrote:
> If there are multiple active queues while sharing a tag set, it's not
> necessary to limit the available tags as same share for each active queue
> if no one ever failed to get driver tag. And fall back to same share if
> someone do failed to get driver tag.
> 
> This modification will be beneficial if total queue_depth of disks
> on the same host is less than total tags.

This patch adds new atomic operations in the hot path and hence probably
has a negative performance impact. What is the performance impact of
this patch for e.g. null_blk when submitting I/O from all CPU cores?

Thanks,

Bart.

  parent reply	other threads:[~2021-07-31 17:15 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12  3:18 [PATCH] blk-mq: allow hardware queue to get more tag while sharing a tag set Yu Kuai
2021-07-12  3:19 ` yukuai (C)
2021-07-20 12:33 ` yukuai (C)
2021-07-31  7:13   ` yukuai (C)
2021-07-31 17:15 ` Bart Van Assche [this message]
2021-08-02 13:34   ` yukuai (C)
2021-08-02 16:17     ` Bart Van Assche
2021-08-03  2:57       ` yukuai (C)
2021-08-03 18:38         ` Bart Van Assche
2021-08-06  1:50           ` yukuai (C)
2021-08-06  2:43             ` Bart Van Assche
2021-08-14  9:43               ` yukuai (C)
2021-08-16  4:16                 ` Bart Van Assche

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