On Tue, 2006-25-04 at 08:17 +1000, Herbert Xu wrote:
> On Mon, Apr 24, 2006 at 02:15:37PM -0400, jamal wrote:
> > 
> > So overall, I am not too impressed with performance on the DP310.
> 
> Hmm, did you try binding the interrupt to individual CPUs? That's pretty
> important for performance.
> 

I tried it - doesnt help. In general it doesnt harm to bind but is not a
guarantee.
My observation with NAPI though is it doesnt make much of a difference
actually given NAPI virtually "binds" an interface to a CPU;  unless:
- you have a bad interrupt distribution in which case binding helps
ensure not everything goes to the same CPU. The C3 is very good 
- or a good APIC + a large of cache ex. in the range of 1MB cache - the
c3 has only 64KB. There is still quiet a few things like the route cache
that are shared by the CPUs; so ping-ponging is unavoidable.

The cases where i observed degraded performance from binding
are I think in celerons and earlier XEONs.

I also tried tying both to a single CPU showed degraded performance as
well - which means a single CPU wasnt capable of handling 170Mbps.
I think i was still able to do total 120Mbps or so.

cheers,
jamal

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