Hello Avi,
On Mon, 2010-08-02 at 19:32 +0300, Avi Kivity wrote:
When are you seeing gup_fast() fall back to gup()? It should be at
most
once per page (when a guest starts up none of its pages are mapped,
it
faults them in on demand).
netperf/netserver latency results are pretty good for
: Thursday, July 29, 2010 7:15 PM
To: net...@vger.kernel.org; kvm@vger.kernel.org; linux-ker...@vger.kernel.org;
m...@redhat.com; mi...@elte.hu; da...@davemloft.net;
herb...@gondor.apana.org.au;
jd...@linux.intel.com
Subject: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net.
We
On Wednesday 04 August 2010, Dong, Eddie wrote:
Arnd Bergmann wrote:
On Friday 30 July 2010 17:51:52 Shirley Ma wrote:
I think it should be less duplicated code in the kernel if we use
macvtap to support what media passthrough driver here. Since macvtap
has support virtio_net head and
Hello Eddie,
On Wed, 2010-08-04 at 10:06 +0800, Dong, Eddie wrote:
But zero-copy is a Linux generic feature that can be used by other
VMMs as well if the BE service drivers want to incorporate. If we can
make mp device VMM-agnostic (it may be not yet in current patch), that
will help Linux
...@linux.intel.com
Subject: Re: [RFC PATCH v8 00/16] Provide a zero-copy method on KVM virtio-net.
Hello Xiaohui,
On Thu, 2010-07-29 at 19:14 +0800, xiaohui@intel.com wrote:
The idea is simple, just to pin the guest VM user space and then
let host NIC driver has the chance to directly DMA
Hello Xiaohui,
On Tue, 2010-08-03 at 16:48 +0800, Xin, Xiaohui wrote:
May you share me with your performance results (including BW and
latency)on
vhost-net and how you get them(your configuration and especially with
the affinity
settings)?
My macvtap zero copy is incomplete, I am testing
Arnd Bergmann wrote:
On Friday 30 July 2010 17:51:52 Shirley Ma wrote:
On Fri, 2010-07-30 at 16:53 +0800, Xin, Xiaohui wrote:
Since vhost-net already supports macvtap/tun backends, do you think
whether it's better to implement zero copy in macvtap/tun than
inducing a new media passthrough
Hello Avi,
On Sun, 2010-08-01 at 11:18 +0300, Avi Kivity wrote:
I don't understand. Under what conditions do you use
get_user_pages()
instead of get_user_pages_fast()? Why?
The code always calls get_user_pages_fast, however, the page will be
unpinned in skb_free if the same page is not
Hello Michael,
On Sun, 2010-08-01 at 11:31 +0300, Michael S. Tsirkin wrote:
I think we should explore the idea for the driver to fall back on data
copy
for small message sizes.
The benefit of zero copy would then be CPU utilization on large
messages.
Yes, we used to have 128 bytes for small
Hello Michael,
On Sun, 2010-08-01 at 11:31 +0300, Michael S. Tsirkin wrote:
Could you provide an example of a good setup?
Specifically, is it a good idea for the vhost thread
to inherit CPU affinities from qemu?
I need to retest my set up with multi-threads vhost. My previous set up
applies
On 08/02/2010 07:01 PM, Shirley Ma wrote:
Hello Avi,
On Sun, 2010-08-01 at 11:18 +0300, Avi Kivity wrote:
I don't understand. Under what conditions do you use
get_user_pages()
instead of get_user_pages_fast()? Why?
The code always calls get_user_pages_fast, however, the page will be
On Mon, 2010-08-02 at 19:11 +0300, Avi Kivity wrote:
I don't understand this. gup_fast() only calls gup() if the page is
swapped out or read-only.
Oh, I used the page as read-only on xmit path. Should I use write
instead?
Thanks
Shirley
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On 08/02/2010 07:25 PM, Shirley Ma wrote:
On Mon, 2010-08-02 at 19:11 +0300, Avi Kivity wrote:
I don't understand this. gup_fast() only calls gup() if the page is
swapped out or read-only.
Oh, I used the page as read-only on xmit path. Should I use write
instead?
No, for xmit getting the
On 07/30/2010 06:46 PM, Shirley Ma wrote:
Hello Avi,
On Fri, 2010-07-30 at 08:02 +0300, Avi Kivity wrote:
get_user_pages() is indeed slow. But what about
get_user_pages_fast()?
Note that when the page is first touched, get_user_pages_fast() falls
back to get_user_pages(), so the latency
On Thu, Jul 29, 2010 at 03:31:22PM -0700, Shirley Ma wrote:
I did some vhost performance measurement over 10Gb ixgbe, and found that
in order to get consistent BW results, netperf/netserver, qemu, vhost
threads smp affinities are required.
Could you provide an example of a good setup?
On Friday 30 July 2010 17:51:52 Shirley Ma wrote:
On Fri, 2010-07-30 at 16:53 +0800, Xin, Xiaohui wrote:
Since vhost-net already supports macvtap/tun backends, do you think
whether it's better to implement zero copy in macvtap/tun than
inducing
a new media passthrough device here?
Hello Xiaohui,
On Thu, 2010-07-29 at 19:14 +0800, xiaohui@intel.com wrote:
The idea is simple, just to pin the guest VM user space and then
let host NIC driver has the chance to directly DMA to it.
The patches are based on vhost-net backend driver. We add a device
which provides proto_ops
Hello Avi,
On Fri, 2010-07-30 at 08:02 +0300, Avi Kivity wrote:
get_user_pages() is indeed slow. But what about
get_user_pages_fast()?
Note that when the page is first touched, get_user_pages_fast() falls
back to get_user_pages(), so the latency needs to be measured after
quite a bit of
Hello Xiaohui,
On Fri, 2010-07-30 at 16:53 +0800, Xin, Xiaohui wrote:
Since vhost-net already supports macvtap/tun backends, do you think
whether it's better to implement zero copy in macvtap/tun than
inducing
a new media passthrough device here?
I'm not sure if there will be more
We provide an zero-copy method which driver side may get external
buffers to DMA. Here external means driver don't use kernel space
to allocate skb buffers. Currently the external buffer can be from
guest virtio-net driver.
The idea is simple, just to pin the guest VM user space and then
let host
Hello Xiaohui,
On Thu, 2010-07-29 at 19:14 +0800, xiaohui@intel.com wrote:
The idea is simple, just to pin the guest VM user space and then
let host NIC driver has the chance to directly DMA to it.
The patches are based on vhost-net backend driver. We add a device
which provides
On 07/30/2010 01:31 AM, Shirley Ma wrote:
Our goal is to improve the bandwidth and reduce the CPU usage.
Exact performance data will be provided later.
I did some vhost performance measurement over 10Gb ixgbe, and found that
in order to get consistent BW results, netperf/netserver, qemu,
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