On Friday 24 March 2006 22:16, Mike Galbraith wrote:
> This patch does various interactivity cleanups.
I have trouble with this patch. By your own admission this patch does 4
different things which one patch shouldn't.
> 1. Removes the barrier between kernel threads and user tasks wrt
> dynamic priority handling.
This is a bad idea. Subjecting a priority ceiling to kernel threads because
they spend a long time idle is not the same as a user task that may be an
idle bomb. Most kernel threads do sleep for extended periods and will always
end up hitting this ceiling. That could lead to some difficult to understand
latencies in scheduling of kernel threads, even if they are nice -5 because
they'll expire very easily.
> 2. Removes the priority barrier for IO.
Bad again. This caused the biggest detriment on interbench numbers and is by
far the most palpable interactivity killer in linux. I/O hurts us lots and
this change will be very noticeable.
> 3. Treats TASK_INTERACTIVE as a transition point that all tasks must
> stop at prior to being promoted further.
Why? Makes no sense. You end up getting hiccups in the rise of priority of
tasks instead of it happening smoothly with sleep.
> 4. Moves division out of the fast path and into scheduler_tick().
> While doing so, tightens timeslice accounting, since it's free, and is
> the flip-side of the reason for having nanosecond sched_clock().
Seems fine.
Cheers,
Con
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
