From: "Michael S. Tsirkin" <mst@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: virtualization@lists.linux-foundation.org,
"Ira W. Snyder" <iws@ovro.caltech.edu>,
netdev@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] vhost_net: a kernel-level virtio server
Date: Thu, 13 Aug 2009 09:06:15 +0300 [thread overview]
Message-ID: <20090813060615.GC3029@redhat.com> (raw)
In-Reply-To: <200908121959.47222.arnd@arndb.de>
On Wed, Aug 12, 2009 at 07:59:47PM +0200, Arnd Bergmann wrote:
> The trick is to swap the virtqueues instead. virtio-net is actually
> mostly symmetric in just the same way that the physical wires on a
> twisted pair ethernet are symmetric (I like how that analogy fits).
You need to really squint hard for it to look symmetric.
For example, for RX, virtio allocates an skb, puts a descriptor on a
ring and waits for host to fill it in. Host system can not do the same:
guest does not have access to host memory.
You can do a copy in transport to hide this fact, but it will kill
performance.
--
MST
next prev parent reply other threads:[~2009-08-13 6:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1249930169.git.mst@redhat.com>
2009-08-10 18:53 ` [PATCH 1/2] export cpu_tlbstate to modules Michael S. Tsirkin
2009-08-10 21:56 ` H. Peter Anvin
2009-08-10 22:06 ` Michael S. Tsirkin
2009-08-10 22:24 ` H. Peter Anvin
2009-08-11 11:19 ` Michael S. Tsirkin
2009-08-10 18:53 ` [PATCH 2/2] vhost_net: a kernel-level virtio server Michael S. Tsirkin
2009-08-10 19:51 ` Arnd Bergmann
2009-08-10 20:10 ` Michael S. Tsirkin
2009-08-10 22:16 ` Arnd Bergmann
2009-08-12 17:03 ` Arnd Bergmann
2009-08-12 17:19 ` Ira W. Snyder
2009-08-12 17:31 ` Michael S. Tsirkin
2009-08-12 17:48 ` Ira W. Snyder
2009-08-13 5:55 ` Michael S. Tsirkin
2009-08-12 17:21 ` Michael S. Tsirkin
2009-08-12 17:59 ` Arnd Bergmann
2009-08-12 19:27 ` Anthony Liguori
2009-08-13 6:31 ` Michael S. Tsirkin
2009-08-13 6:06 ` Michael S. Tsirkin [this message]
2009-08-13 13:38 ` Arnd Bergmann
2009-08-13 13:48 ` Arnd Bergmann
2009-08-13 14:41 ` Michael S. Tsirkin
2009-08-13 14:53 ` Arnd Bergmann
2009-08-13 15:37 ` Avi Kivity
2009-08-20 7:25 ` Rusty Russell
2009-08-13 14:39 ` Michael S. Tsirkin
2009-08-13 14:58 ` Arnd Bergmann
2009-08-13 15:03 ` Michael S. Tsirkin
2009-08-12 19:22 ` Anthony Liguori
2009-08-13 8:45 ` Michael S. Tsirkin
2009-08-13 13:45 ` Arnd Bergmann
2009-08-12 19:58 ` Paul E. McKenney
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