Commits
Jiri Olsa committed 5a1078043f8
sched/core: Move sched_entity::avg into separate cache line
The sched_entity::avg collides with read-mostly sched_entity data.
The perf c2c tool showed many read HITM accesses across
many CPUs for sched_entity's cfs_rq and my_q, while having
at the same time tons of stores for avg.
After placing sched_entity::avg into separate cache line,
the perf bench sched pipe showed around 20 seconds speedup.
NOTE I cut out all perf events except for cycles and
instructions from following output.
Before:
$ perf stat -r 5 perf bench sched pipe -l 10000000
# Running 'sched/pipe' benchmark:
# Executed 10000000 pipe operations between two processes
Total time: 270.348 [sec]
27.034805 usecs/op
36989 ops/sec
...
245,537,074,035 cycles # 1.433 GHz
187,264,548,519 instructions # 0.77 insns per cycle
272.653840535 seconds time elapsed ( +- 1.31% )
After:
$ perf stat -r 5 perf bench sched pipe -l 10000000
# Running 'sched/pipe' benchmark:
# Executed 10000000 pipe operations between two processes
Total time: 251.076 [sec]
25.107678 usecs/op
39828 ops/sec
...
244,573,513,928 cycles # 1.572 GHz
187,409,641,157 instructions # 0.76 insns per cycle
251.679315188 seconds time elapsed ( +- 0.31% )
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1449606239-28602-1-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>