From: Sasha Levin <levinsasha928@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: markmc@redhat.com, kvm@vger.kernel.org,
"Michael S. Tsirkin" <mst@redhat.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] virtio-ring: Use threshold for switching to indirect descriptors
Date: Sun, 04 Dec 2011 19:39:34 +0200 [thread overview]
Message-ID: <1323020374.3256.5.camel@lappy> (raw)
In-Reply-To: <4EDBAFC5.2010405@redhat.com>
On Sun, 2011-12-04 at 19:37 +0200, Avi Kivity wrote:
> On 12/04/2011 07:34 PM, Sasha Levin wrote:
> > >
> > > I'm confused. didn't you see a bigger benefit for guest->host by
> > > switching indirect off?
> >
> > The 5% improvement is over the 'regular' indirect on, not over indirect
> > off. Sorry for the confusion there.
> >
> > I suggested this change regardless of the outcome of indirect descriptor
> > threshold discussion, since it would help anyways.
>
> For net, this makes sense. For block, it reduces the effective queue
> depth, so it's not a trivial change. It probably makes sense there too,
> though.
It doesn't have to be limited at that number, anything above that can go
through the regular kmalloc() path.
--
Sasha.
WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <levinsasha928@gmail.com>
To: Avi Kivity <avi@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
markmc@redhat.com
Subject: Re: [PATCH] virtio-ring: Use threshold for switching to indirect descriptors
Date: Sun, 04 Dec 2011 19:39:34 +0200 [thread overview]
Message-ID: <1323020374.3256.5.camel@lappy> (raw)
In-Reply-To: <4EDBAFC5.2010405@redhat.com>
On Sun, 2011-12-04 at 19:37 +0200, Avi Kivity wrote:
> On 12/04/2011 07:34 PM, Sasha Levin wrote:
> > >
> > > I'm confused. didn't you see a bigger benefit for guest->host by
> > > switching indirect off?
> >
> > The 5% improvement is over the 'regular' indirect on, not over indirect
> > off. Sorry for the confusion there.
> >
> > I suggested this change regardless of the outcome of indirect descriptor
> > threshold discussion, since it would help anyways.
>
> For net, this makes sense. For block, it reduces the effective queue
> depth, so it's not a trivial change. It probably makes sense there too,
> though.
It doesn't have to be limited at that number, anything above that can go
through the regular kmalloc() path.
--
Sasha.
next prev parent reply other threads:[~2011-12-04 17:39 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-29 9:33 [PATCH] virtio-ring: Use threshold for switching to indirect descriptors Sasha Levin
2011-11-29 9:33 ` Sasha Levin
2011-11-29 12:56 ` Michael S. Tsirkin
2011-11-29 12:56 ` Michael S. Tsirkin
2011-11-29 13:34 ` Sasha Levin
2011-11-29 13:34 ` Sasha Levin
2011-11-29 13:54 ` Michael S. Tsirkin
2011-11-29 13:54 ` Michael S. Tsirkin
2011-11-29 14:21 ` Sasha Levin
2011-11-29 14:21 ` Sasha Levin
2011-11-29 14:54 ` Michael S. Tsirkin
2011-11-29 14:54 ` Michael S. Tsirkin
2011-11-29 14:58 ` Avi Kivity
2011-11-29 14:58 ` Avi Kivity
2011-11-30 16:11 ` Sasha Levin
2011-11-30 16:11 ` Sasha Levin
2011-11-30 16:17 ` Sasha Levin
2011-11-30 16:17 ` Sasha Levin
2011-12-01 2:42 ` Rusty Russell
2011-12-01 2:42 ` Rusty Russell
2011-12-01 7:58 ` Michael S. Tsirkin
2011-12-01 7:58 ` Michael S. Tsirkin
2011-12-01 8:09 ` Sasha Levin
2011-12-01 8:09 ` Sasha Levin
2011-12-01 10:26 ` Michael S. Tsirkin
2011-12-01 10:26 ` Michael S. Tsirkin
2011-12-02 0:46 ` Rusty Russell
2011-12-02 0:46 ` Rusty Russell
2011-12-03 11:50 ` Sasha Levin
2011-12-03 11:50 ` Sasha Levin
2011-12-04 11:06 ` Michael S. Tsirkin
2011-12-04 11:06 ` Michael S. Tsirkin
2011-12-04 15:15 ` Michael S. Tsirkin
2011-12-04 15:15 ` Michael S. Tsirkin
2011-12-04 11:52 ` Avi Kivity
2011-12-04 11:52 ` Avi Kivity
2011-12-04 12:01 ` Michael S. Tsirkin
2011-12-04 12:01 ` Michael S. Tsirkin
2011-12-04 12:06 ` Avi Kivity
2011-12-04 12:06 ` Avi Kivity
2011-12-04 15:11 ` Michael S. Tsirkin
2011-12-04 15:11 ` Michael S. Tsirkin
2011-12-04 15:16 ` Avi Kivity
2011-12-04 15:16 ` Avi Kivity
2011-12-04 16:00 ` Michael S. Tsirkin
2011-12-04 16:00 ` Michael S. Tsirkin
2011-12-04 16:33 ` Avi Kivity
2011-12-04 16:33 ` Avi Kivity
2011-12-05 0:10 ` Rusty Russell
2011-12-05 0:10 ` Rusty Russell
2011-12-05 9:52 ` Avi Kivity
2011-12-05 9:52 ` Avi Kivity
2011-12-06 5:07 ` Rusty Russell
2011-12-06 5:07 ` Rusty Russell
2011-12-06 9:58 ` Avi Kivity
2011-12-06 9:58 ` Avi Kivity
2011-12-06 12:03 ` Rusty Russell
2011-12-06 12:03 ` Rusty Russell
2011-12-07 13:37 ` Avi Kivity
2011-12-07 13:37 ` Avi Kivity
2011-12-04 12:13 ` Sasha Levin
2011-12-04 12:13 ` Sasha Levin
2011-12-04 16:22 ` Michael S. Tsirkin
2011-12-04 16:22 ` Michael S. Tsirkin
2011-12-04 17:34 ` Sasha Levin
2011-12-04 17:34 ` Sasha Levin
2011-12-04 17:37 ` Avi Kivity
2011-12-04 17:37 ` Avi Kivity
2011-12-04 17:39 ` Sasha Levin [this message]
2011-12-04 17:39 ` Sasha Levin
2011-12-04 18:23 ` Sasha Levin
2011-12-04 18:23 ` Sasha Levin
2011-12-07 14:02 ` Sasha Levin
2011-12-07 14:02 ` Sasha Levin
2011-12-07 15:48 ` Michael S. Tsirkin
2011-12-07 15:48 ` Michael S. Tsirkin
2011-12-08 9:44 ` Rusty Russell
2011-12-08 9:44 ` Rusty Russell
2011-12-08 10:37 ` Sasha Levin
2011-12-08 10:37 ` Sasha Levin
2011-12-09 5:33 ` Rusty Russell
2011-12-09 5:33 ` Rusty Russell
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