Re: Huge performance degradation for UDP between 2.4.17 and 2.6

From: Eric Dumazet
Date: Thu Aug 02 2012 - 10:14:05 EST


On Thu, 2012-08-02 at 14:27 +0200, leroy christophe wrote:
> Hi
>
> I'm having a big issue with UDP. Using a powerpc board (MPC860).
>
> With our board running kernel 2.4.17, I'm able to send 160000 voice
> packets (UDP, 96 bytes per packet) in 11 seconds.
> With the same board running either Kernel 2.6.35.14 or Kernel 3.4.7, I
> need 55 seconds to send the same amount of packets.
>
>
> Is there anything to tune in order to get same output rate as with
> Kernel 2.4 ?

kernel size is probably too big for your old / slow cpu.

Maybe you added too many features on your 3.4.7 kernel. (netfilter ?
SLUB debugging ...)

Its hard to say, 2.4.17 had less features and was faster.



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