lkml.org 
[lkml]   [2006]   [Jan]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] [RFC] Optimize select/poll by putting small data sets on the stack
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.

(I believe that select()/poll() based daemons are mostly non multi-threaded,
since high performance multi-threaded programs should be using epoll...)

Eric

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

\
 
 \ /
  Last update: 2006-01-03 23:16    [W:0.057 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site