lkml.org 
[lkml]   [2000]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRE: [patch] scheduler bugfix, SMP, 2.4.0-test7

On Mon, 28 Aug 2000, Dimitris Michailidis wrote:

> > the attached sched-2.4.0-test7-C1 patch fixes a 'missed wakeup'
> > SMP-scheduler bug.
>
> +running_again:
> + if (prev == idle_task(smp_processor_id()))
> + goto out_unlock;
>
> Why don't you move the test for the idle task to the beginning of the
> function so we don't need to take the run queue lock if prev is idle? There
> is nothing to be done for idle tasks, we don't even need to set ->has_cpu.

for performance reasons. The whole running_again path is extremely rare
(because the window for a re-wakeup is small), so i moved all checks into
the slow path and made the common code fall-through.

Ingo

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 12:38    [W:0.083 / U:3.608 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site