From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [RFC PATCH 0/8] virtio: new API for addition of buffers, scatterlist changes
Date: Thu, 07 Feb 2013 14:30:54 +0100 [thread overview]
Message-ID: <5113AC8E.5030508@redhat.com> (raw)
In-Reply-To: <20130207133133.GC21707@redhat.com>
Il 07/02/2013 14:31, Michael S. Tsirkin ha scritto:
> > Single means *this piece* (for example a request header) is single. It
> > could still end up in an indirect buffer because QEMU does not support
> > mixed direct/indirect buffers.
>
> Yes but why is the optimization worth it?
> It makes sense if all we want to do is add a single buffer
> in one go, this would give us virtqueue_add_buf_single.
>
> But if we are building up an s/g list anyway,
> speeding up one of the entries a tiny bit
> seems very unlikely to be measureable.
> No?
There is some optimization potential even in unrolling the loop, but
yes, it looks like I misunderstood. I'll add virtqueue_add_buf_single
instead.
Paolo
next prev parent reply other threads:[~2013-02-07 13:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-07 12:22 [RFC PATCH 0/8] virtio: new API for addition of buffers, scatterlist changes Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 1/8] virtio: add functions for piecewise addition of buffers Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 2/8] virtio-blk: reorganize virtblk_add_req Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 3/8] virtio-blk: use virtqueue_start_buf on bio path Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 4/8] virtio-blk: use virtqueue_start_buf on req path Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 5/8] scatterlist: introduce sg_unmark_end Paolo Bonzini
2013-02-07 12:35 ` Jens Axboe
2013-02-07 12:22 ` [RFC PATCH 6/8] virtio-net: unmark scatterlist ending after virtqueue_add_buf Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 7/8] virtio-scsi: use virtqueue_start_buf Paolo Bonzini
2013-02-07 12:22 ` [RFC PATCH 8/8] virtio: reimplement virtqueue_add_buf using new functions Paolo Bonzini
2013-02-07 13:09 ` [RFC PATCH 0/8] virtio: new API for addition of buffers, scatterlist changes Michael S. Tsirkin
2013-02-07 13:14 ` Paolo Bonzini
2013-02-07 13:23 ` Michael S. Tsirkin
2013-02-07 13:20 ` Paolo Bonzini
2013-02-07 13:31 ` Michael S. Tsirkin
2013-02-07 13:30 ` Paolo Bonzini [this message]
2013-02-08 4:05 ` Rusty Russell
2013-02-08 6:35 ` Paolo Bonzini
2013-02-08 11:52 ` Jens Axboe
2013-02-13 9:46 ` Rusty Russell
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=5113AC8E.5030508@redhat.com \
--to=pbonzini@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=virtualization@lists.linux-foundation.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