Subject: Re: TCP_STREAM performance regression on commit b3613118

From: "Alex,Shi" <[email-masked]>
Date: Mon, 20 Feb 2012 09:44:13 +0800

On Fri, 2012-02-17 at 13:33 -0500, David Miller wrote:
> From: Eric Dumazet <[email-masked]>
> Date: Fri, 17 Feb 2012 10:50:39 +0100
> 
> > Le vendredi 17 février 2012 à 16:18 +0800, Alex,Shi a écrit :
> >> The tcp_stream loop back performance has about 10% drop on the
> >> commitment on our core2 2 sockets server. This commit has 2
> >> parents(7505afe28, 5983fe), but both of them have no regression. So
> >> guess the impact just happened when this 2 parents joint. That beyond
> >> our capability to dig it more.
> >> 
> >> Any ideas? 
> > 
> > Most probably the more accurate truesize determination is responsible of
> > this tcp regression, since some prior assumptions might be wrong.
> > 
> > Want to give more information on the workload ?
> > Is it a 32 or 64 bit kernel ?

It is 64 bit kernel. Currently we only care 64bit. 

Will try to bring more statistic after our lab recovered. 
> 
> And let's start CC:'ing netdev too.