Messages in this thread | | | Date | Sun, 9 Dec 2001 15:50:04 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: Linux 2.4.17-pre5 |
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On Sun, 9 Dec 2001, Mike Kravetz wrote:
> On Sun, Dec 09, 2001 at 04:24:59PM +0000, Alan Cox wrote: > > I'm currently using the following rule in wake up > > > > if(current->mm->runnable > 0) /* One already running ? */ > > cpu = current->mm->last_cpu; > > else > > cpu = idle_cpu(); > > else > > cpu = cpu_num[fast_fl1(runnable_set)] > > > > that is > > If we are running threads with this mm on a cpu throw them at the > > same core > > If there is an idle CPU use it > > Take the mask of currently executing priority levels, find the last > > set bit (lowest pri) being executed, and look up a cpu running at > > that priority > > > > Then the idle stealing code will do the rest of the balancing, but at least > > it converges towards each mm living on one cpu core. > > This implies that the idle loop will poll looking for work to do. > Is that correct? Davide's scheduler also does this. I believe > the current default idle loop (at least for i386) does as little > as possible and stops execting instructions. Comments in the code > mention power consumption. Should we be concerned with this?
My idea is not to poll ( due energy issues ) but to wake up idles ( kernel/timer.c ) at every timer tick to let them monitor the overall balancing status.
- Davide
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