From: "Michael S. Tsirkin" <mst@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Krishna Kumar2 <krkumar2@in.ibm.com>,
David Miller <davem@davemloft.net>,
kvm@vger.kernel.org, Shirley Ma <mashirle@us.ibm.com>,
netdev@vger.kernel.org, steved@us.ibm.com
Subject: Re: Network performance with small packets
Date: Wed, 9 Feb 2011 03:55:06 +0200 [thread overview]
Message-ID: <20110209015506.GA13289@redhat.com> (raw)
In-Reply-To: <201102091209.36546.rusty@rustcorp.com.au>
On Wed, Feb 09, 2011 at 12:09:35PM +1030, Rusty Russell wrote:
> On Wed, 9 Feb 2011 11:23:45 am Michael S. Tsirkin wrote:
> > On Wed, Feb 09, 2011 at 11:07:20AM +1030, Rusty Russell wrote:
> > > On Wed, 2 Feb 2011 03:12:22 pm Michael S. Tsirkin wrote:
> > > > On Wed, Feb 02, 2011 at 10:09:18AM +0530, Krishna Kumar2 wrote:
> > > > > > "Michael S. Tsirkin" <mst@redhat.com> 02/02/2011 03:11 AM
> > > > > >
> > > > > > On Tue, Feb 01, 2011 at 01:28:45PM -0800, Shirley Ma wrote:
> > > > > > > On Tue, 2011-02-01 at 23:21 +0200, Michael S. Tsirkin wrote:
> > > > > > > > Confused. We compare capacity to skb frags, no?
> > > > > > > > That's sg I think ...
> > > > > > >
> > > > > > > Current guest kernel use indirect buffers, num_free returns how many
> > > > > > > available descriptors not skb frags. So it's wrong here.
> > > > > > >
> > > > > > > Shirley
> > > > > >
> > > > > > I see. Good point. In other words when we complete the buffer
> > > > > > it was indirect, but when we add a new one we
> > > > > > can not allocate indirect so we consume.
> > > > > > And then we start the queue and add will fail.
> > > > > > I guess we need some kind of API to figure out
> > > > > > whether the buf we complete was indirect?
> > >
> > > I've finally read this thread... I think we need to get more serious
> > > with our stats gathering to diagnose these kind of performance issues.
> > >
> > > This is a start; it should tell us what is actually happening to the
> > > virtio ring(s) without significant performance impact...
> > >
> > > Subject: virtio: CONFIG_VIRTIO_STATS
> > >
> > > For performance problems we'd like to know exactly what the ring looks
> > > like. This patch adds stats indexed by how-full-ring-is; we could extend
> > > it to also record them by how-used-ring-is if we need.
> > >
> > > Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
> >
> > Not sure whether the intent is to merge this. If yes -
> > would it make sense to use tracing for this instead?
> > That's what kvm does.
>
> Intent wasn't; I've not used tracepoints before, but maybe we should
> consider a longer-term monitoring solution?
>
> Patch welcome!
>
> Cheers,
> Rusty.
Sure, I'll look into this.
--
MST
next prev parent reply other threads:[~2011-02-09 1:55 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-25 21:09 Network performance with small packets Steve Dobbelstein
2011-01-26 15:17 ` Michael S. Tsirkin
2011-01-27 18:44 ` Shirley Ma
2011-01-27 19:00 ` Michael S. Tsirkin
2011-01-27 19:09 ` Shirley Ma
2011-01-27 19:31 ` Michael S. Tsirkin
2011-01-27 19:45 ` Shirley Ma
2011-01-27 20:05 ` Michael S. Tsirkin
2011-01-27 20:15 ` Shirley Ma
2011-01-28 18:29 ` Steve Dobbelstein
2011-01-28 22:51 ` Steve Dobbelstein
2011-02-01 15:52 ` [PATCHv2 dontapply] vhost-net tx tuning Michael S. Tsirkin
2011-02-01 23:07 ` Sridhar Samudrala
2011-02-01 23:27 ` Shirley Ma
2011-02-02 4:36 ` Michael S. Tsirkin
2011-01-27 21:02 ` Network performance with small packets David Miller
2011-01-27 21:30 ` Shirley Ma
2011-01-28 12:16 ` Michael S. Tsirkin
2011-02-01 0:24 ` Steve Dobbelstein
2011-02-01 1:30 ` Sridhar Samudrala
2011-02-01 5:56 ` Michael S. Tsirkin
2011-02-01 21:09 ` Shirley Ma
2011-02-01 21:24 ` Michael S. Tsirkin
2011-02-01 21:32 ` Shirley Ma
2011-02-01 21:42 ` Michael S. Tsirkin
2011-02-01 21:53 ` Shirley Ma
2011-02-01 21:56 ` Michael S. Tsirkin
2011-02-01 22:59 ` Shirley Ma
2011-02-02 4:40 ` Michael S. Tsirkin
2011-02-02 6:05 ` Shirley Ma
2011-02-02 6:19 ` Shirley Ma
2011-02-02 6:29 ` Michael S. Tsirkin
2011-02-02 7:14 ` Shirley Ma
2011-02-02 7:33 ` Shirley Ma
2011-02-02 10:49 ` Michael S. Tsirkin
2011-02-02 15:42 ` Shirley Ma
2011-02-02 15:48 ` Michael S. Tsirkin
2011-02-02 17:12 ` Shirley Ma
2011-02-02 18:20 ` Michael S. Tsirkin
2011-02-02 18:26 ` Shirley Ma
2011-02-02 10:48 ` Michael S. Tsirkin
2011-02-02 6:34 ` Krishna Kumar2
2011-02-02 7:03 ` Shirley Ma
2011-02-02 7:37 ` Krishna Kumar2
2011-02-02 10:48 ` Michael S. Tsirkin
2011-02-02 15:39 ` Shirley Ma
2011-02-02 15:47 ` Michael S. Tsirkin
2011-02-02 17:10 ` Shirley Ma
2011-02-02 17:32 ` Michael S. Tsirkin
2011-02-02 18:11 ` Shirley Ma
2011-02-02 18:27 ` Michael S. Tsirkin
2011-02-02 19:29 ` Shirley Ma
2011-02-02 20:17 ` Michael S. Tsirkin
2011-02-02 21:03 ` Shirley Ma
2011-02-02 21:20 ` Michael S. Tsirkin
2011-02-02 21:41 ` Shirley Ma
2011-02-03 5:59 ` Michael S. Tsirkin
2011-02-03 6:09 ` Shirley Ma
2011-02-03 6:16 ` Michael S. Tsirkin
2011-02-03 5:05 ` Shirley Ma
2011-02-03 6:13 ` Michael S. Tsirkin
2011-02-03 15:58 ` Shirley Ma
2011-02-03 16:20 ` Michael S. Tsirkin
2011-02-03 17:18 ` Shirley Ma
2011-02-01 5:54 ` Michael S. Tsirkin
2011-02-01 17:23 ` Michael S. Tsirkin
[not found] ` <1296590943.26937.797.camel@localhost.localdomain>
[not found] ` <20110201201715.GA30050@redhat.com>
2011-02-01 20:25 ` Shirley Ma
2011-02-01 21:21 ` Michael S. Tsirkin
2011-02-01 21:28 ` Shirley Ma
2011-02-01 21:41 ` Michael S. Tsirkin
2011-02-02 4:39 ` Krishna Kumar2
2011-02-02 4:42 ` Michael S. Tsirkin
2011-02-09 0:37 ` Rusty Russell
2011-02-09 0:53 ` Michael S. Tsirkin
2011-02-09 1:39 ` Rusty Russell
2011-02-09 1:55 ` Michael S. Tsirkin [this message]
2011-02-09 7:43 ` Stefan Hajnoczi
2011-03-08 21:57 ` Shirley Ma
2011-03-09 2:21 ` Andrew Theurer
2011-03-09 15:42 ` Shirley Ma
2011-03-10 1:49 ` Rusty Russell
2011-04-12 20:01 ` Michael S. Tsirkin
2011-04-14 11:28 ` Rusty Russell
2011-04-14 12:40 ` Michael S. Tsirkin
2011-04-14 16:03 ` Michael S. Tsirkin
2011-04-19 0:33 ` Rusty Russell
2011-02-02 18:38 ` Michael S. Tsirkin
2011-02-02 19:15 ` Steve Dobbelstein
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