lkml.org 
[lkml]   [2005]   [Jun]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 1/6] new timeofday core subsystem for -mm (v.B3)
FromLee Revell <>
DateMon, 20 Jun 2005 19:44:56 -0400
On Mon, 2005-06-20 at 14:53 -0700, john stultz wrote:
> Yea, honestly I doubt gettimefoday performance will ever be as good as
> rdtsc. I mean, that's a single instruction vs syscall overhead +
> hardware clock reading + frequency conversion + ntp adjustment. Its
> just not a fair comparison.

Of course not, the patch would have to be magic for that to happen.

But some user space apps are now *required* to use rdtsc for timing due
to the massive performance difference. If we only took a 5x or 10x
performance hit vs rdtsc, rather than the current 50x, it might be
enough that user space apps won't have to do this.

Lee

-
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: 2005-06-21 03:31    [from the cache]
©2003-2010