From: Bernhard Schmidt <berni@birkenwald.de>
To: Sridhar Samudrala <samudrala.sridhar@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: virtio GSO makes IPv6 unbearably slow
Date: Tue, 2 Feb 2010 10:32:47 +0100 [thread overview]
Message-ID: <20100202093247.GA5592@schleppi.birkenwald.de> (raw)
In-Reply-To: <4B67C175.9030409@gmail.com>
On Mon, Feb 01, 2010 at 10:08:53PM -0800, Sridhar Samudrala wrote:
> >According to ethtool GSO is enabled on the guest, but disabling it using
> >ethtool does not have any effect. But giving the kernel
> >"virtio_net.gso=0" in append fixes the issue completely.
> >
> >Anyone having any ideas?
> >
> I ran into a similar problem when using Intel e1000e driver on the
> host. Found a bug in most of the intel ethernet drivers when handling
> large GSO IPv6 packets.
> You can see the fix i submitted here
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8e1e8a4779cb23c1d9f51e9223795e07ec54d77a
>
> But you seem to be using Intel e100 driver. So i am not sure you are
> running into the same issue.
> You could try disabling both tso and gso on the guest using ethtool.
Disabling anything inside the guest doesn't help anything, as told
above. I have to disable gso using a kernel parameter in the virtio_net
driver.
> On the host, do you have gso/tso enabled on the uplink e100 driver?
On the host everything is disabled.
Offload parameters for eth0:
rx-checksumming: off
tx-checksumming: off
scatter-gather: off
tcp-segmentation-offload: off
udp-fragmentation-offload: off
generic-segmentation-offload: off
generic-receive-offload: off
large-receive-offload: off
Best Regards,
Bernhard
prev parent reply other threads:[~2010-02-02 9:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-01 19:50 virtio GSO makes IPv6 unbearably slow Bernhard Schmidt
2010-02-02 6:08 ` Sridhar Samudrala
2010-02-02 9:32 ` Bernhard Schmidt [this message]
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