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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.

  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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