From: Julian Stecklina <jsteckli@os.inf.tu-dresden.de>
Cc: "snabb-devel@googlegroups.com" <snabb-devel@googlegroups.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [snabb-devel:276] Re: snabbswitch integration with QEMU for userspace ethernet I/O
Date: Tue, 28 May 2013 17:33:45 +0200 [thread overview]
Message-ID: <51A4CE59.6060307@os.inf.tu-dresden.de> (raw)
In-Reply-To: <CAA2XHbfjBtL9KoO9tc8OLjowk4EUX3oudd+ufE1WNQ3M5WLNig@mail.gmail.com>
On 05/28/2013 04:42 PM, Luke Gorrie wrote:
> On 28 May 2013 13:53, Michael S. Tsirkin <mst@redhat.com
> <mailto:mst@redhat.com>> wrote:
>
> Yes, you can maybe trade some of this latency for power/CPU cycles by
> aggressive polling. Doing this in a way that does not waste a lot of
> power would be tricky.
>
>
> For what it's worth, here is my mental model right now:
>
> Administrator budgets one CPU core for network I/O (VM and NIC).
> Switch uses that CPU to deliver sufficient speed (e.g. 10 M packets/sec
> ~ 40Gbps).
> Switch uses micro-sleeps to cut cpu usage to ~ 1% in idle periods.
With virtio the backend can decide whether it wants to be notified by
the client. If you disable all notifications you are in polling mode. If
your backend/switch doesn't find anything to do it can reenable
notifications and block. Thus you would naturally revert to non-polling
mode, when the network load is low.
Julian
next prev parent reply other threads:[~2013-05-28 15:34 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-26 9:32 [Qemu-devel] snabbswitch integration with QEMU for userspace ethernet I/O Luke Gorrie
2013-05-27 9:34 ` Stefan Hajnoczi
2013-05-27 15:18 ` Michael S. Tsirkin
2013-05-27 15:43 ` Paolo Bonzini
2013-05-27 16:18 ` Anthony Liguori
2013-05-27 16:18 ` Paolo Bonzini
2013-05-27 17:01 ` Anthony Liguori
2013-05-27 17:13 ` Michael S. Tsirkin
2013-05-27 18:31 ` Anthony Liguori
2013-05-28 10:39 ` Luke Gorrie
2013-05-28 10:10 ` Luke Gorrie
2013-05-28 10:35 ` Stefan Hajnoczi
2013-05-28 11:36 ` Julian Stecklina
2013-05-28 11:53 ` Michael S. Tsirkin
2013-05-28 12:09 ` Julian Stecklina
2013-05-28 13:56 ` Michael S. Tsirkin
2013-05-28 15:35 ` Julian Stecklina
2013-05-28 15:44 ` Michael S. Tsirkin
2013-05-28 12:48 ` [Qemu-devel] [snabb-devel:276] " Luke Gorrie
2013-05-28 13:12 ` Julian Stecklina
2013-05-28 13:42 ` [Qemu-devel] [snabb-devel:280] " Luke Gorrie
2013-05-28 14:42 ` [Qemu-devel] [snabb-devel:276] " Luke Gorrie
2013-05-28 15:33 ` Julian Stecklina [this message]
2013-05-28 17:00 ` [Qemu-devel] " Anthony Liguori
2013-05-28 17:17 ` Michael S. Tsirkin
2013-05-28 18:55 ` Anthony Liguori
2013-05-29 10:31 ` Stefano Stabellini
2013-05-29 12:25 ` Michael S. Tsirkin
2013-05-29 13:04 ` Stefano Stabellini
2013-06-04 12:19 ` [Qemu-devel] [snabb-devel:300] " Luke Gorrie
2013-06-04 12:49 ` Julian Stecklina
2013-06-04 20:09 ` [Qemu-devel] [snabb-devel:326] " Luke Gorrie
2013-06-04 12:56 ` [Qemu-devel] [snabb-devel:300] " Michael S. Tsirkin
2013-06-05 6:09 ` [Qemu-devel] [snabb-devel:327] " Luke Gorrie
2013-05-29 7:49 ` [Qemu-devel] " Stefan Hajnoczi
2013-05-29 9:08 ` Michael S. Tsirkin
2013-05-29 14:21 ` Stefan Hajnoczi
2013-05-29 14:48 ` Michael S. Tsirkin
2013-05-29 16:02 ` Julian Stecklina
2013-05-30 2:35 ` ronnie sahlberg
2013-05-30 6:46 ` Stefan Hajnoczi
2013-05-30 6:55 ` Michael S. Tsirkin
2013-05-30 7:11 ` [Qemu-devel] [snabb-devel:308] " Luke Gorrie
2013-05-30 8:08 ` [Qemu-devel] " Julian Stecklina
2013-05-29 12:32 ` Julian Stecklina
2013-05-29 14:31 ` Stefan Hajnoczi
2013-05-29 15:59 ` Julian Stecklina
2013-05-28 11:58 ` Stefan Hajnoczi
2013-10-21 10:29 ` Luke Gorrie
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