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From: Jason Wang <jasowang@redhat.com>
To: Sahid Ferdjaoui <sahid.ferdjaoui@cloudwatt.com>, kvm@vger.kernel.org
Subject: Re: virtio: Large number of tcp connections, vhost_net seems to be a bottleneck
Date: Wed, 23 Oct 2013 20:30:44 +0800	[thread overview]
Message-ID: <5267C174.5040407@redhat.com> (raw)
In-Reply-To: <533233212.1710860.1382256273232.JavaMail.root@cloudwatt.com>

On 10/20/2013 04:04 PM, Sahid Ferdjaoui wrote:
> Hi all,
>
> I'm working on create a large number of tcp connections on a guest;
> The environment is on OpenStack:
>
> Host (dedicated compute node):
>   OS/Kernel: Ubuntu/3.2
>   Cpus: 24
>   Mems: 128GB
>
> Guest (alone on the Host):
>   OS/Kernel: Ubuntu/3.2
>   Cpus: 4
>   Mems: 32GB
>
> Currently a guest can handle about 700 000 established connections, the cpus are not loaded and 12giga of memory are used.
> I'm working to understand why I can go up...
>
> On my host, after several tests with different versions of openvswitch and with linux bridge,
> It look like the process vhost_net is the only process loaded to 100% and it seems vhost_net cannot use more than 1 cpu.
>
> I would like to get more informations about vhost_net and if there is a solution to configure it to use more than 1 cpu?

You can if you enable the multiqueue support for virtio-net, it can use
N threads when there's N queue pairs.

See http://www.linux-kvm.org/page/Multiqueue for more information.
> Thanks a lot,
> s.
> --
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      parent reply	other threads:[~2013-10-23 12:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <7677902.1710678.1382256256542.JavaMail.root@cloudwatt.com>
2013-10-20  8:04 ` virtio: Large number of tcp connections, vhost_net seems to be a bottleneck Sahid Ferdjaoui
2013-10-20 15:52   ` Mike Dawson
2013-10-21  8:50     ` Sahid Ferdjaoui
2013-10-23 12:30   ` Jason Wang [this message]

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