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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-07-05 10:56:32 +0200
committerIngo Molnar <mingo@elte.hu>2011-07-05 11:28:18 +0200
commite4c2fb0d5776b58049d2556b456144a4db3fe5a9 (patch)
tree04cebbb24f524408728492cfeb396d66aa6127e4 /include/linux/sched.h
parentcd62287e364c0d15d517c6ced4e4808b54711475 (diff)
sched: Disable (revert) SCHED_LOAD_SCALE increase
Alex reported that commit c8b281161df ("sched: Increase SCHED_LOAD_SCALE resolution") caused a power usage regression under light load as it increases the number of load-balance operations and keeps idle cpus from staying idle. Time has run out to find the root cause for this release so disable the feature for v3.0 until we can figure out what causes the problem. Reported-by: "Alex, Shi" <alex.shi@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nikhil Rao <ncrao@google.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-m4onxn0sxnyn5iz9o88eskc3@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a837b20ba19..496770a9648 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -808,7 +808,7 @@ enum cpu_idle_type {
* when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the
* increased costs.
*/
-#if BITS_PER_LONG > 32
+#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load */
# define SCHED_LOAD_RESOLUTION 10
# define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION)
# define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION)