lkml.org 
[lkml]   [2006]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [patch] x86: unify/rewrite SMP TSC sync code
From
Date
On Fri, 2006-11-24 at 18:56 -0800, Wink Saville wrote:
> Ingo Molnar wrote:
> > * Andi Kleen <ak@suse.de> wrote:
> >
> > a new CPU is added. If the TSC isnt sync on SMP then it quickly gets
> > pretty messy, and we should rather take a look at /why/ these apps are
> > using RDTSC.
> >
> > Ingo
> > -
>
> I use RDTSC in get a cheap method of measuring time. What other choices are
> there for a low overhead high frequency time source?
>
> By low overhead a kernel call is way to expensive, I want to minimally impact
> the code and have many of these calls through out the code. One of the
> ways I use it is to instrument multi-threaded applications and then use
> the TSC to compare when actions occur between threads. i.e. I use it as a
> time stamp counter and neither precision or accuracy is too important.
> On the other hand the more precise and accurate the better:)

so you can live with an occasional jump of seconds/minutes between
threads? Or when a thread moves to another cpu?
(yes on many PCs you won't see minutes, but on others you will)

--
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

-
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: 2006-11-25 09:33    [W:0.225 / U:0.184 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site