Subject: Re: Slow speed of tcp connections in a network namespace

From: Andrew Vagin <[email-masked]>
Date: Sat, 29 Dec 2012 22:29:01 +0400

On Sat, Dec 29, 2012 at 09:40:28AM -0800, Eric Dumazet wrote:
> On Sat, 2012-12-29 at 18:50 +0400, Andrew Vagin wrote:
> > On Sat, Dec 29, 2012 at 05:53:23AM -0800, Eric Dumazet wrote:
> > > > 3.8-rc1 is used for experiments.
> > > > 
> > > > Do you have any ideas where is a problem?
> > > 
> > > veth has absolutely no offload features
> > > 
> > > It needs some care...
> > > 
> > > At the very miminum, let TCP coalesce do its job by allowing SG
> > > 
> > > CC Michał Mirosław <[email-masked]> for insights.
> > > 
> > > Please try following patch :
> > 
> > Hello Eric,
> > 
> > Thanks for your feedback.
> > 
> > With this patch the results is a bit better (~4MB/s), but it's much less
> > than in the root netns.
> 
> Please post your new tcpdump then ;)

I have rebooted the host and a speed in a netns is again about 1.7MB/s. I
don't know why it was 4MB/s in the previous time.

new tcpdump and netstat are attached

> 
> also post "netstat -s" from root and test ns after your wgets
> 
> 
>