Eric Dumazet a écrit :
> Andi Kleen a écrit :
>> This is a RFC for now. I would be interested in testing
>> feedback. Patch is for 2.6.15.
>>
>> Optimize select and poll by a using stack space for small fd sets
>>
>> This brings back an old optimization from Linux 2.0. Using
>> the stack is faster than kmalloc. On a Intel P4 system
>> it speeds up a select of a single pty fd by about 13%
>> (~4000 cycles -> ~3500)
> 
> Was this result on UP or SMP kernel ? Preempt or not ?
> 
> I think we might play in do_pollfd() and use fget_light()/fput_light() 
> instead of fget()/fput() that are somewhat expensive because of atomic 
> inc/dec on SMP.
> 

Just for completeness I include this patch against 2.6.15