lkml.org 
[lkml]   [2002]   [Dec]   [21]   [last100]   RSS Feed
Views: [more markup]   [less markup]   [headers]   [forward]  
 
Messages in this thread
/
DateSat, 21 Dec 2002 17:07:06 +0100
FromChristian Leber <>
SubjectRe: Intel P6 vs P7 system call performance
On Wed, Dec 18, 2002 at 12:25:38AM -0500, Brian Gerst wrote:

> How about this patch?  Instead of making a per-cpu trampoline, write to 
> the msr during each context switch.  This means that the stack pointer 
> is valid at all times, and also saves memory and a cache line bounce.  I 
> also included some misc cleanups.

Just a little bit of benchmarking:
(little testprogram by Linus out of this thread)
(on a AMD Duron 750)

2.5.52-bk2+sysenter-1 (Brian Gerst):
igor3:~# ./a.out
187.894946 cycles    (call 0xfffff000)
299.155075 cycles    (int $0x80)
2.5.52-bk6:
igor3:~# ./a.out
202.134535 cycles    (call 0xffffe000)
299.117583 cycles    (int $0x80)
Not really much, but the difference is there. (I don't about other side
effects)


Christian Leber

-
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: 2005-03-22 11:31    [W:0.202 / U:0.130 seconds]
©2003-2008 Jasper Spaans