linux/kernel/sched
Tim Chen ed61bbc69c sched/balancing: Reduce the rate of needless idle load balancing
The current no_hz idle load balancer do load balancing for *all* idle cpus,
even though the time due to load balance for a particular
idle cpu could be still a while in the future.  This introduces a much
higher load balancing rate than what is necessary.  The patch
changes the behavior by only doing idle load balancing on
behalf of an idle cpu only when it is due for load balancing.

On SGI's systems with over 3000 cores, the cpu responsible for idle balancing
got overwhelmed with idle balancing, and introduces a lot of OS noise
to workloads.  This patch fixes the issue.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Russ Anderson <rja@sgi.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Hedi Berriche <hedi@sgi.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: MichelLespinasse <walken@google.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1400621967.2970.280.camel@schen9-DESK
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-06-05 11:52:01 +02:00
..
auto_group.c
auto_group.h
clock.c
completion.c
core.c sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice() 2014-05-22 11:16:36 +02:00
cpuacct.c
cpuacct.h
cpudeadline.c
cpudeadline.h
cpupri.c
cpupri.h
cputime.c
deadline.c sched/rt: Fix 'struct sched_dl_entity' and dl_task_time() comments, to match the current upstream code 2014-05-22 11:16:37 +02:00
debug.c
fair.c sched/balancing: Reduce the rate of needless idle load balancing 2014-06-05 11:52:01 +02:00
features.h
idle.c
idle_task.c
Makefile
proc.c
rt.c sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
sched.h sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
stats.c
stats.h
stop_task.c sched, nohz: Change rq->nr_running to always use wrappers 2014-05-22 11:16:33 +02:00
wait.c