From: Christoph Hellwig <hch@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] scsi: Remove some false sharing in Scsi_Host / Scsi_Device
Date: Sun, 13 Jul 2014 04:46:21 -0700 [thread overview]
Message-ID: <20140713114621.GA4316@infradead.org> (raw)
In-Reply-To: <1405110310-3555-1-git-send-email-andi@firstfloor.org>
On Fri, Jul 11, 2014 at 01:25:10PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> These data structures are accessed by different CPUs and have some
> fields which are mostly read only and others which are frequently
> written. Separate some common ones into separate cache line
> to minimize false sharing while submitting a command.
>
> This allows scsi_dispatch_cmd to do more work with shared clean
> cache lines.
>
> - Move the cmd_serial_number to the end before the host data
> - Separate write common fields from read mostly fields in
> the scsi device
Looks useful, but please provide some numbers on how this actually
helps.
prev parent reply other threads:[~2014-07-13 11:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-11 20:25 Andi Kleen
2014-07-13 11:46 ` Christoph Hellwig [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140713114621.GA4316@infradead.org \
--to=hch@infradead.org \
--cc=ak@linux.intel.com \
--cc=andi@firstfloor.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®