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From: Shirley Ma <mashirle@us.ibm.com>
To: "Xin, Xiaohui" <xiaohui.xin@intel.com>
Cc: Avi Kivity <avi@redhat.com>, David Miller <davem@davemloft.net>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"mst@redhat.com" <mst@redhat.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [RFC PATCH 2/2] macvtap: TX zero copy between guest and host kernel
Date: Tue, 14 Sep 2010 19:40:52 -0700	[thread overview]
Message-ID: <1284518452.13351.111.camel@localhost.localdomain> (raw)
In-Reply-To: <F2E9EB7348B8264F86B6AB8151CE2D792B8C8152A0@shsmsx502.ccr.corp.intel.com>

On Wed, 2010-09-15 at 09:50 +0800, Xin, Xiaohui wrote:
> I think what David said is what we have thought before in mp device.
> Since we are not sure the exact time the tx buffer was wrote though
> DMA operation.
> But the deadline is when the tx buffer was freed. So we only notify
> the vhost stuff
> about the write when tx buffer freed. But the deadline is maybe too
> late for performance.

Have you tried it? If so what's the performance penalty you have seen by
notifying vhost when tx buffer freed?

I am thinking to have a callback in skb destructor,
vhost_add_used_and_signal gets updated when skb is actually freed, vhost
vq & head need to be passed to the callback. This might requires vhost
ring size is at least as big as the lower device driver. 

Thanks
Shirley


  reply	other threads:[~2010-09-15  2:41 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-13 20:43 [RFC PATCH 0/1] macvtap TX zero copy between guest and host kernel Shirley Ma
2010-09-13 20:47 ` RFC PATCH 1/2] macvtap: A new sock zero copy flag Shirley Ma
2010-09-13 20:48 ` [RFC PATCH 2/2] macvtap: TX zero copy between guest and host kernel Shirley Ma
2010-09-14  3:17   ` David Miller
2010-09-14  9:12     ` Avi Kivity
2010-09-14 15:05       ` Shirley Ma
2010-09-14 15:21         ` Arnd Bergmann
2010-09-14 15:22           ` Michael S. Tsirkin
2010-09-14 16:00             ` Shirley Ma
2010-09-14 16:29               ` Michael S. Tsirkin
2010-09-14 17:02                 ` Shirley Ma
2010-09-14 18:27                   ` Michael S. Tsirkin
2010-09-14 18:49                     ` Shirley Ma
2010-09-14 19:01                       ` Michael S. Tsirkin
2010-09-14 19:20                         ` Shirley Ma
2010-09-15  5:31                           ` Michael S. Tsirkin
2010-09-14 19:36                         ` Shirley Ma
2010-09-15  5:12                           ` Michael S. Tsirkin
2010-09-15  6:21                             ` Shirley Ma
2010-09-15 10:10                               ` Michael S. Tsirkin
2010-09-15 14:52                                 ` Shirley Ma
2010-09-15 15:04                                   ` Michael S. Tsirkin
2010-09-15 15:39                                     ` Michael S. Tsirkin
2010-09-15 17:00                                       ` Shirley Ma
2010-09-15 17:30                                         ` Michael S. Tsirkin
2010-09-15 18:48                                           ` Shirley Ma
2010-09-29  3:24                                   ` Shirley Ma
2010-09-29  8:16                                     ` Michael S. Tsirkin
2010-09-29  8:28                                       ` Michael S. Tsirkin
2010-09-29 14:33                                         ` Shirley Ma
2010-09-29 14:56                                         ` Shirley Ma
2010-09-29 14:31                                       ` Shirley Ma
2010-09-29 14:37                                       ` Shirley Ma
2010-09-29 15:14                                     ` Michael S. Tsirkin
2010-09-29 15:23                                       ` Shirley Ma
2010-09-15  2:46                 ` Xin, Xiaohui
2010-09-15  9:58                   ` Michael S. Tsirkin
2010-09-16  8:18                     ` Xin, Xiaohui
2010-09-16 10:02                       ` Michael S. Tsirkin
2010-09-15  1:56           ` Xin, Xiaohui
2010-09-15  1:50         ` Xin, Xiaohui
2010-09-15  2:40           ` Shirley Ma [this message]
2010-09-15  2:55             ` Xin, Xiaohui
2010-09-15  5:27             ` Michael S. Tsirkin
2010-09-15  6:17               ` Shirley Ma
2010-09-14 12:05 ` [RFC PATCH 0/1] macvtap " Michael S. Tsirkin
2010-09-14 15:15   ` Shirley Ma

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