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

From: jamal <[email-masked]>
Date: Sat, 01 May 2010 07:23:34 -0400

On Sat, 2010-05-01 at 07:57 +0200, Eric Dumazet wrote:

> I changed your program a bit to use EV_PERSIST, (to avoid epoll_ctl()
> overhead for each packet...)

Thats a different test case then ;-> You can also get rid of the timer
(I doubt it will show much difference in results) - I have it in there
because it i am trying to replicate what i saw causing the regression.

> RPS off : 220.000 pps 
> 
> RPS on (ee mask) : 700.000 pps  (with a slightly modified tg3 driver)
> 96% of delivered packets
> 

That's a very very huge gap. What were the numbers before you changed to
EV_PERSIST?
Note: i did not add any of your other patches for dst refcnt, sockets
etc. Were you running with those patches in these tests? I will try the
next opportunity i get to have latest kernel + those patches. 

> This is on tg3 adapter, and tg3 has copybreak feature : small packets
> are copied into skb of the right size.

Ok, so the driver tuning is also important then (and it shows in the
profile).

cheers,
jamal