Re: Huge performance degradation for UDP between 2.4.17 and 2.6

[LEROY christophe]

Le 02/08/2012 16:13, Eric Dumazet a Ãcrit :
> 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.

Thanks for your answer.
Yes I have netfilter as I need it. However, I tried without it and still 
need about 37 seconds to send the 160000 packets I was sending in 11 
seconds with 2.4.17

I don't think there is any problem with size of the kernel. I still have 
plenty of memory available.

All debugging is turned off, and I'm not using SLUB but SLOB.
I have 32Mbytes of RAM. Would SLUB be more performant than SLOB ?

Christophe
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/