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From: Shirley Ma <mashirle@us.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>,
	Steve Dobbelstein <steved@us.ibm.com>,
	David Miller <davem@davemloft.net>,
	kvm@vger.kernel.org, mashirle@linux.vnet.ibm.com,
	netdev@vger.kernel.org
Subject: Re: Network performance with small packets
Date: Tue, 01 Feb 2011 13:53:05 -0800	[thread overview]
Message-ID: <1296597185.26937.829.camel@localhost.localdomain> (raw)
In-Reply-To: <20110201214211.GB31105@redhat.com>

On Tue, 2011-02-01 at 23:42 +0200, Michael S. Tsirkin wrote:
> On Tue, Feb 01, 2011 at 01:32:35PM -0800, Shirley Ma wrote:
> > On Tue, 2011-02-01 at 23:24 +0200, Michael S. Tsirkin wrote:
> > > My theory is that the issue is not signalling.
> > > Rather, our queue fills up, then host handles
> > > one packet and sends an interrupt, and we
> > > immediately wake the queue. So the vq
> > > once it gets full, stays full.
> > 
> > >From the printk debugging output, it might not be exactly the case.
> The
> > ring gets full, run a bit, then gets full, then run a bit, then
> full...
> 
> Yes, but does it get even half empty in between?

Sometimes, most of them not half of empty in between. But printk slow
down the traffics, so it's not accurate. I think your patch will improve
the performance if it signals guest when half of the ring size is
empty. 

But you manage signal by using TX bytes, I would like to change it to
half of the ring size instead for signaling. Is that OK?

Shirley




  reply	other threads:[~2011-02-01 21:53 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 [this message]
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
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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