Subject: Re: [PATCH net-next-2.6] net: speedup udp receive path

From: jamal <[email-masked]>
Date: Wed, 28 Apr 2010 19:44:53 -0400

On Wed, 2010-04-28 at 16:06 +0200, Eric Dumazet wrote:

> Here it is ;)

Sorry - things got a little hectic with TheMan.

I am afraid i dont have good news.
Actually, I should say i dont have good news in regards to rps.
For my sample app, two things seem to be happening:
a) The overall performance has gotten better for both rps
and non-rps.
b) non-rps is now performing relatively better

This is just what i see in net-next not related to your patch.
It seems the kernels i tested prior to April 23 showed rps better.
The one i tested on Apr23 showed rps being about the same as non-rps.
As i stated in my last result posting, I thought i didnt test properly
but i did again today and saw the same thing. And now non-rps is
_consistently_ better.
So some regression is going on...

Your patch has improved the performance of rps relative to what is in
net-next very lightly; but it has also improved the performance of
non-rps;->
My traces look different for the app cpu than yours - likely because of
the apps being different.

At the moment i dont have time to dig deeper into code, but i could
test as cycles show up.

I am attaching the profile traces and results.

cheers,
jamal