From: Christoph Hellwig <hch@lst.de>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v6 0/6] Disable fair tag sharing for UFS devices
Date: Mon, 4 Dec 2023 08:52:52 +0100 [thread overview]
Message-ID: <20231204075252.GA29579@lst.de> (raw)
In-Reply-To: <20231130193139.880955-1-bvanassche@acm.org>
On Thu, Nov 30, 2023 at 11:31:27AM -0800, Bart Van Assche wrote:
> Hi Jens,
>
> The fair tag sharing algorithm reduces performance for UFS devices
> significantly. This is because UFS devices have multiple logical units, a
> limited queue depth (32 for UFS 3.1 devices), because it happens often that
> multiple logical units are accessed and also because it takes time to
> give tags back after activity on a request queue has stopped. This patch series
> restores UFS device performance to that of the legacy block layer by disabling
> fair tag sharing for UFS devices.
I feel like a broken record:
fair tag sharing exists for a reason. Opting out of it for a specific
driver does not make any sense. Either you can make a good argument
why you don't want it at all, or for specific configurations you
can clearly explain, or you make it work faster. A "treat my driver
special" flag is never acceptable.
next prev parent reply other threads:[~2023-12-04 7:52 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 19:31 [PATCH v6 0/6] Disable fair tag sharing for UFS devices Bart Van Assche
2023-11-30 19:31 ` [PATCH v6 1/4] block: Make fair tag sharing configurable Bart Van Assche
2023-12-01 12:52 ` Johannes Thumshirn
2023-12-01 22:14 ` Bart Van Assche
2023-12-02 7:21 ` Yu Kuai
2023-12-04 4:13 ` Bart Van Assche
2023-12-25 12:51 ` Yu Kuai
2023-12-26 2:22 ` Bart Van Assche
2024-01-11 19:22 ` Bart Van Assche
2024-01-12 1:08 ` Yu Kuai
2024-01-12 4:39 ` Christoph Hellwig
2024-01-14 3:22 ` Yu Kuai
2024-01-15 5:59 ` Christoph Hellwig
2024-01-15 6:18 ` Yu Kuai
2024-01-16 2:59 ` Bart Van Assche
2024-01-16 10:24 ` Yu Kuai
2024-01-16 17:36 ` Bart Van Assche
2024-01-18 7:31 ` Christoph Hellwig
2024-01-18 18:40 ` Bart Van Assche
2024-01-23 9:13 ` Christoph Hellwig
2024-01-23 15:16 ` Bart Van Assche
2024-01-24 9:08 ` Christoph Hellwig
2024-01-30 0:03 ` Bart Van Assche
2024-01-31 6:22 ` Christoph Hellwig
2024-01-31 21:32 ` Bart Van Assche
2024-01-31 21:37 ` Keith Busch
2024-01-31 21:42 ` Bart Van Assche
2024-01-31 23:04 ` Keith Busch
2024-01-31 23:41 ` Bart Van Assche
2024-01-31 23:52 ` Damien Le Moal
2024-01-16 2:52 ` Bart Van Assche
2023-11-30 19:31 ` [PATCH v6 2/4] scsi: core: Make fair tag sharing configurable in the host template Bart Van Assche
2023-11-30 19:31 ` [PATCH v6 3/4] scsi: core: Make fair tag sharing configurable via sysfs Bart Van Assche
2023-11-30 19:31 ` [PATCH v6 4/4] scsi: ufs: Disable fair tag sharing Bart Van Assche
2023-12-04 7:52 ` Christoph Hellwig [this message]
2023-12-05 3:15 ` [PATCH v6 0/6] Disable fair tag sharing for UFS devices Bart Van Assche
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