From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH] nvme: set DMA_ATTR_WEAK_ORDERING attribute on dma buffers
Date: Sat, 17 Jun 2017 13:57:03 +0200 [thread overview]
Message-ID: <20170617115703.GA13002@lst.de> (raw)
In-Reply-To: <1497645290-31041-1-git-send-email-alan.adamson@oracle.com>
On Fri, Jun 16, 2017@01:34:50PM -0700, Alan Adamson wrote:
> SPARC based platforms suffer significant read performance penalties for
> nvme reads when Relaxed Ordering is not enabled. This change sets the
> DMA_ATTR_WEAK_ORDERING (Relaxed Ordering) attribute for nvme block dma
> buffers.
Please explain what it does exactly, and why you think it's safe for NVMe,
as that belongs into the changelog.
Bonus points for explaining why DMA_ATTR_WEAK_ORDERING shouldn't
be the default behavior for the dma_map_ routines instead of sprinkling
it over just about every driver..
next prev parent reply other threads:[~2017-06-17 11:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-16 20:34 [PATCH] nvme: set DMA_ATTR_WEAK_ORDERING attribute on dma buffers Alan Adamson
2017-06-17 11:57 ` Christoph Hellwig [this message]
2017-06-21 20:30 ` Alan Adamson
2017-06-24 7:35 ` DMA_ATTR_WEAK_ORDERING defintion, was " Christoph Hellwig
2017-06-26 9:15 ` Arnd Bergmann
2017-06-27 20:46 ` chris hyser
2017-07-05 19:07 ` Christoph Hellwig
2017-07-10 16:17 ` chris hyser
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=20170617115703.GA13002@lst.de \
--to=hch@lst.de \
/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