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From: Bart Van Assche <bvanassche@acm.org>
To: Avri Altman <Avri.Altman@wdc.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Akinobu Mita <akinobu.mita@gmail.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Stanley Chu <stanley.chu@mediatek.com>,
	Can Guo <cang@codeaurora.org>,
	Asutosh Das <asutoshd@codeaurora.org>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Bean Huo <beanhuo@micron.com>
Subject: Re: [PATCH v2 13/19] scsi: ufs: Fix a race in the completion path
Date: Tue, 13 Jul 2021 16:26:54 -0700	[thread overview]
Message-ID: <1b35777f-bea2-9443-0bac-c42b37acf8b3@acm.org> (raw)
In-Reply-To: <fe3076c3-f835-b7e4-c5be-4ba55d5e0e41@acm.org>

On 7/13/21 9:49 AM, Bart Van Assche wrote:
> On 7/11/21 5:29 AM, Avri Altman wrote:
>>> This patch is a performance improvement because it reduces the number of
>>> atomic operations in the hot path (test_and_clear_bit()).
>> Both Can & Stanley reported a performance improvement of RR with 
>> "Optimize host lock..".
>> Can those short numerical studies can be repeated with this patch?
> 
> I will measure the performance impact of this patch for rq_affinity=2 as 
> soon as I have the time. As you may know we are close to an internal 
> deadline.

(replying to my own email)

Hi Avri,

The performance I measure with the current upstream UFS driver is 61.0 K 
IOPS. With a variant of this patch (outstanding_reqs protected with a 
new spinlock instead of the host lock), I see 62.0 K IOPS. In other 
words, this patch realizes a small performance improvement. This is what 
I had expected since this patch reduces the number of atomic operations 
involved in updating outstanding_reqs.

Thanks,

Bart.

  reply	other threads:[~2021-07-13 23:27 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09 20:26 [PATCH] fault-inject: Declare the second argument of setup_fault_attr() const Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 00/19] UFS patches for kernel v5.15 Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 01/19] scsi: Fix the documentation of the scsi_execute() time parameter Bart Van Assche
2021-07-10  8:17   ` Hannes Reinecke
2021-07-13  1:40   ` Martin K. Petersen
2021-07-09 20:26 ` [PATCH v2 02/19] scsi: ufs: Reduce power management code duplication Bart Van Assche
2021-07-14  9:24   ` Bean Huo
2021-07-09 20:26 ` [PATCH v2 03/19] scsi: ufs: Only include power management code if necessary Bart Van Assche
2021-07-14 20:38   ` Bean Huo
2021-07-09 20:26 ` [PATCH v2 04/19] scsi: ufs: Rename the second ufshcd_probe_hba() argument Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 05/19] scsi: ufs: Use DECLARE_COMPLETION_ONSTACK() where appropriate Bart Van Assche
2021-07-14 20:40   ` Bean Huo
2021-07-09 20:26 ` [PATCH v2 06/19] scsi: ufs: Remove ufshcd_valid_tag() Bart Van Assche
2021-07-14 21:10   ` Bean Huo
2021-07-09 20:26 ` [PATCH v2 07/19] scsi: ufs: Verify UIC locking requirements at runtime Bart Van Assche
2021-07-14 21:14   ` Bean Huo
2021-07-09 20:26 ` [PATCH v2 08/19] scsi: ufs: Improve static type checking for the host controller state Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 09/19] scsi: ufs: Remove several wmb() calls Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 10/19] scsi: ufs: Inline ufshcd_outstanding_req_clear() Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 11/19] scsi: ufs: Rename __ufshcd_transfer_req_compl() Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 12/19] scsi: ufs: Remove a local variable Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 13/19] scsi: ufs: Fix a race in the completion path Bart Van Assche
2021-07-11 12:29   ` Avri Altman
2021-07-11 12:37     ` Avri Altman
2021-07-13 16:49     ` Bart Van Assche
2021-07-13 23:26       ` Bart Van Assche [this message]
2021-07-16 12:39         ` Avri Altman
2021-07-16 16:26           ` Asutosh Das (asd)
2021-07-16 16:54             ` Bart Van Assche
2021-07-16 17:51               ` Bart Van Assche
2021-07-16 16:50           ` Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 14/19] scsi: ufs: Use the doorbell register instead of the UTRLCNR register Bart Van Assche
2021-07-16  8:59   ` Avri Altman
2021-07-09 20:26 ` [PATCH v2 15/19] scsi: ufs: Fix the SCSI abort handler Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 16/19] scsi: ufs: Request sense data asynchronously Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 17/19] scsi: ufs: Synchronize SCSI and UFS error handling Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 18/19] scsi: ufs: Retry aborted SCSI commands instead of completing these successfully Bart Van Assche
2021-07-09 20:26 ` [PATCH v2 19/19] scsi: ufs: Add fault injection support Bart Van Assche
2021-07-09 21:56   ` Randy Dunlap
2021-07-09 22:45     ` Bart Van Assche
2021-07-09 20:32 ` [PATCH] fault-inject: Declare the second argument of setup_fault_attr() const Bart Van Assche

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