From: Ming Lei <ming.lei@redhat.com>
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: linux-scsi@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Bart Van Assche <bvanassche@acm.org>,
Christoph Hellwig <hch@lst.de>,
John Garry <john.garry@huawei.com>
Subject: Re: [PATCH V2] scsi: put hot fields of scsi_host_template into one cacheline
Date: Thu, 23 Apr 2020 09:48:48 +0800 [thread overview]
Message-ID: <20200423014848.GA331623@T590> (raw)
In-Reply-To: <1587566490.3485.7.camel@HansenPartnership.com>
On Wed, Apr 22, 2020 at 07:41:30AM -0700, James Bottomley wrote:
> On Wed, 2020-04-22 at 17:54 +0800, Ming Lei wrote:
> > The following three fields of scsi_host_template are referenced in
> > scsi IO submission path, so put them together into one cacheline:
> >
> > - cmd_size
> > - queuecommand
> > - commit_rqs
>
> Are there benchmarks to show this actually makes a difference, if so,
> how much?
Originally I observed 40% IOPS boost on scsi_debug by moving the three
fields into scsi_host, but I lost that test environment now.
When I run fio on scsi_debug in another machine, IOPS gets ~10% boost
with this patch.
Thanks,
Ming
next prev parent reply other threads:[~2020-04-23 1:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 9:54 [PATCH V2] scsi: put hot fields of scsi_host_template into one cacheline Ming Lei
2020-04-22 10:06 ` John Garry
2020-04-22 14:36 ` Bart Van Assche
2020-04-22 14:41 ` James Bottomley
2020-04-23 1:48 ` Ming Lei [this message]
2020-04-23 6:02 ` Christoph Hellwig
2020-04-24 18:14 ` Martin K. Petersen
2020-05-01 22:27 ` Douglas Gilbert
2020-05-04 1:09 ` Ming Lei
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