From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: Steve Dobbelstein <steved@us.ibm.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, Khoa Huynh <khoa@us.ibm.com>,
sri@linux.vnet.ibm.com
Subject: Re: Re: [PATCH] virtio: Use ioeventfd for virtqueue notify
Date: Mon, 04 Oct 2010 10:04:29 +0200 [thread overview]
Message-ID: <4CA98A8D.4000500@redhat.com> (raw)
In-Reply-To: <4CA92B79.2030805@linux.vnet.ibm.com>
On 10/04/2010 03:18 AM, Anthony Liguori wrote:
> On 10/03/2010 09:28 AM, Michael S. Tsirkin wrote:
>>
>>> This is using eventfd as well.
>> Sorry, I meant irqfd.
>
> I've tried using irqfd in userspace. It hurts performance quite a bit
> compared to doing an ioctl so I would suspect this too.
>
> A last_used_idx or similar mechanism should help performance quite a
> bit on top of ioeventfd too.
>
Any idea why? While irqfd does quite a bit of extra locking, it
shouldn't be that bad.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: Steve Dobbelstein <steved@us.ibm.com>,
Anthony Liguori <aliguori@us.ibm.com>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, Khoa Huynh <khoa@us.ibm.com>,
sri@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] Re: [PATCH] virtio: Use ioeventfd for virtqueue notify
Date: Mon, 04 Oct 2010 10:04:29 +0200 [thread overview]
Message-ID: <4CA98A8D.4000500@redhat.com> (raw)
In-Reply-To: <4CA92B79.2030805@linux.vnet.ibm.com>
On 10/04/2010 03:18 AM, Anthony Liguori wrote:
> On 10/03/2010 09:28 AM, Michael S. Tsirkin wrote:
>>
>>> This is using eventfd as well.
>> Sorry, I meant irqfd.
>
> I've tried using irqfd in userspace. It hurts performance quite a bit
> compared to doing an ioctl so I would suspect this too.
>
> A last_used_idx or similar mechanism should help performance quite a
> bit on top of ioeventfd too.
>
Any idea why? While irqfd does quite a bit of extra locking, it
shouldn't be that bad.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2010-10-04 8:04 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-30 14:01 [PATCH] virtio: Use ioeventfd for virtqueue notify Stefan Hajnoczi
2010-09-30 14:01 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-03 11:01 ` Avi Kivity
2010-10-03 11:01 ` [Qemu-devel] " Avi Kivity
2010-10-03 13:51 ` Michael S. Tsirkin
2010-10-03 13:51 ` [Qemu-devel] " Michael S. Tsirkin
2010-10-03 14:21 ` Avi Kivity
2010-10-03 14:21 ` [Qemu-devel] " Avi Kivity
2010-10-03 14:28 ` Michael S. Tsirkin
2010-10-03 14:28 ` [Qemu-devel] " Michael S. Tsirkin
2010-10-04 1:18 ` Anthony Liguori
2010-10-04 1:18 ` [Qemu-devel] " Anthony Liguori
2010-10-04 8:04 ` Avi Kivity [this message]
2010-10-04 8:04 ` Avi Kivity
2010-10-04 14:01 ` Anthony Liguori
2010-10-04 14:01 ` Anthony Liguori
2010-10-04 16:12 ` Michael S. Tsirkin
2010-10-04 16:12 ` Michael S. Tsirkin
2010-10-04 16:20 ` Anthony Liguori
2010-10-04 16:20 ` Anthony Liguori
2010-10-04 16:25 ` Michael S. Tsirkin
2010-10-04 16:25 ` Michael S. Tsirkin
2010-10-04 14:30 ` Stefan Hajnoczi
2010-10-04 14:30 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-05 11:00 ` rukhsana ansari
2010-10-05 11:00 ` [Qemu-devel] " rukhsana ansari
2010-10-05 11:58 ` Avi Kivity
2010-10-05 11:58 ` [Qemu-devel] " Avi Kivity
2010-10-19 13:07 ` Stefan Hajnoczi
2010-10-19 13:07 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-19 13:12 ` Anthony Liguori
2010-10-19 13:12 ` [Qemu-devel] " Anthony Liguori
2010-10-19 13:35 ` Michael S. Tsirkin
2010-10-19 13:35 ` [Qemu-devel] " Michael S. Tsirkin
2010-10-19 13:44 ` Stefan Hajnoczi
2010-10-19 13:44 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-19 13:43 ` Michael S. Tsirkin
2010-10-19 13:43 ` [Qemu-devel] " Michael S. Tsirkin
2010-11-10 14:52 ` Stefan Hajnoczi
2010-11-10 14:52 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-19 13:33 ` Michael S. Tsirkin
2010-10-19 13:33 ` [Qemu-devel] " Michael S. Tsirkin
2010-10-25 13:25 ` Stefan Hajnoczi
2010-10-25 13:25 ` [Qemu-devel] " Stefan Hajnoczi
2010-10-25 15:01 ` Stefan Hajnoczi
2010-10-25 15:01 ` [Qemu-devel] " Stefan Hajnoczi
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=4CA98A8D.4000500@redhat.com \
--to=avi@redhat.com \
--cc=aliguori@linux.vnet.ibm.com \
--cc=aliguori@us.ibm.com \
--cc=khoa@us.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=sri@linux.vnet.ibm.com \
--cc=stefanha@linux.vnet.ibm.com \
--cc=steved@us.ibm.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.