Re: TCP_STREAM performance regression on commit b3613118

On Fri, 2012-02-17 at 13:33 -0500, David Miller wrote:

From: Eric Dumazet <redacted>
Date: Fri, 17 Feb 2012 10:50:39 +0100

quoted

Le vendredi 17 février 2012 à 16:18 +0800, Alex,Shi a écrit :

quoted

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 ?

And let's start CC:'ing netdev too.

Add CC to tang feng, He is working on this issue.