From: Jason Wang <jasowang@redhat.com>
To: wangsitan <wangsitan@aliyun.com>, kvm <kvm@vger.kernel.org>
Subject: Re: virtio-net: how to prevent receiving big packages?
Date: Mon, 04 Nov 2013 12:35:27 +0800 [thread overview]
Message-ID: <5277240F.60800@redhat.com> (raw)
In-Reply-To: <4b97eaf9-34ad-4221-a273-df47d7244c9c@aliyun.com>
On 11/03/2013 04:07 PM, wangsitan wrote:
> Hi all,
>
> A virtual net interface using virtio_net with TSO on may send big TCP packets (up to 64KB). The receiver will get big packets if it's virtio_net, too. But it will get common packets (according to MTU) if the receiver is e1000 (who re-packaged the data?).
>
> The transfer with big packets is more efficient. But there's something wrong with my "receiver" vm whose net-core has been modified. Strange behaviours came out when it received big packets.
>
> I will look at problems on the modified kernel later. What I want to do now is turning off the feature "can receive big packets" of virtio_net in the guest vm (just like I'm using e1000). Is there an easy way to disable it? Or should I change some code in guest's virtio_net?
You can disable the feature of VIRTIO_NET_F_HOST_TSO4 and
VIRTIO_NET_F_HOST_TSO6 by specifying host_tso4=off,guest_tso6=off in
qemu command line.
>
> Thanks a lot.
>
> --
> Best Regards
> Wangsitan
> --
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next prev parent reply other threads:[~2013-11-04 4:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-03 8:07 virtio-net: how to prevent receiving big packages? wangsitan
2013-11-04 4:35 ` Jason Wang [this message]
2013-11-04 5:05 ` Jason Wang
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