lkml.org 
[lkml]   [2001]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: No 100 HZ timer !
On Tue, Apr 10, 2001 at 12:18:03PM +0100, Alan Cox wrote:
> > > interrupting decrementer. (i.e just about any modern chip)
> >
> > Just how would you do kernel/user CPU time accounting then ? It's currently done
> > on every timer tick, and doing it less often would make it useless.
>
> On the contrary doing it less often but at the right time massively improves
> its accuracy. You do it on reschedule. An rdtsc instruction is cheap and all
> of a sudden you have nearly cycle accurate accounting

Does not sound very attractive all at all on non virtual machines (I see the point on
UML/VM):
making system entry/context switch/interrupts slower, making add_timer slower, just to
process a few less timer interrupts. That's like robbing the fast paths for a slow path.

-Andi
-
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 13:24    [W:0.177 / U:0.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site