lkml.org 
[lkml]   [2007]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] change futex_wait() to hrtimers

* Andi Kleen <andi@firstfloor.org> wrote:

> On Mon, Mar 12, 2007 at 12:00:20PM +0100, Thomas Gleixner wrote:
> > On Mon, 2007-03-12 at 12:27 +0100, Andi Kleen wrote:
> > > Ingo Molnar <mingo@elte.hu> writes:
> > > >
> > > > the only correct approach is the use of hrtimers, and a patch exists for
> > > > that - see below. This has been included in -rt for quite some time.
> > >
> > > But isn't that bad for power management? You'll likely get more
> > > idle wakeups, won't you?
> >
> > Why so ? It comes more precise, but only once.
>
> When it's clustered around the jiffies interval then wakeups from
> multiple processes will be somewhat batched. With a precise wakeup
> you'll get wakeups all over the jiffies period, won't you?

if HIGH_RES_TIMERS is disabled then that is what happens. But frankly,
most futex waits are without timeouts - if an application cares about
micro-effects like that then you are much better off not using a
per-futex timeout anyway.

Ingo
-
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: 2007-03-12 12:07    [W:0.066 / U:0.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site