Re: [PATCH] sched/fair: Do not decay new task load on first enqueue
From: Matt Fleming
Date: Tue Oct 18 2016 - 06:29:53 EST
On Tue, 11 Oct, at 11:24:53AM, Matt Fleming wrote:
>
> That's a lot more costly cross-DIE migrations. I think this patch is
> along the right lines, but there's something fishy happening on this
> box.
I wasn't really able to track down why this machine regressed, and the
patch shows enough improvement for other boxes that I think it's worth
sticking in tip/sched/core.
I saw a number of double digit gains for hackbench with this patch.
Here's a 4-cpu box that shows improvements in arithmetic mean and some
nice improvements to the stddev,
hackbench-process-pipes
4.8.0 4.8.0
vanilla find-idle-group-v1r1
Amean 1 3.2580 ( 0.00%) 3.0607 ( 6.06%)
Amean 3 8.0387 ( 0.00%) 8.2027 ( -2.04%)
Amean 5 12.0507 ( 0.00%) 12.1703 ( -0.99%)
Amean 7 16.0027 ( 0.00%) 16.4567 ( -2.84%)
Amean 12 26.9030 ( 0.00%) 21.7767 ( 19.05%)
Amean 16 33.4127 ( 0.00%) 28.9877 ( 13.24%)
Stddev 1 0.1383 ( 0.00%) 0.1787 (-29.22%)
Stddev 3 0.1297 ( 0.00%) 0.1677 (-29.29%)
Stddev 5 0.5495 ( 0.00%) 0.4549 ( 17.22%)
Stddev 7 0.7401 ( 0.00%) 0.6161 ( 16.75%)
Stddev 12 2.3187 ( 0.00%) 0.7102 ( 69.37%)
Stddev 16 4.0734 ( 0.00%) 2.9364 ( 27.91%)
And a 60-cpu box with similar improvements,
hackbench-process-sockets
4.8.0 4.8.0
vanilla find-idle-group-v1r1
Amean 1 32.8810 ( 0.00%) 2.0590 ( 93.74%)
Amean 4 34.8663 ( 0.00%) 3.3177 ( 90.48%)
Amean 7 34.1243 ( 0.00%) 4.3323 ( 87.30%)
Amean 12 36.8373 ( 0.00%) 5.3650 ( 85.44%)
Amean 21 29.0333 ( 0.00%) 6.0280 ( 79.24%)
Amean 30 27.2807 ( 0.00%) 7.2653 ( 73.37%)
Amean 48 23.2453 ( 0.00%) 9.9810 ( 57.06%)
Amean 79 29.6660 ( 0.00%) 16.6680 ( 43.81%)
Amean 110 41.3680 ( 0.00%) 23.1787 ( 43.97%)
Amean 141 45.3720 ( 0.00%) 29.4130 ( 35.17%)
Amean 172 45.6403 ( 0.00%) 34.3783 ( 24.68%)
Amean 203 47.6120 ( 0.00%) 40.0063 ( 15.97%)
Amean 234 50.1703 ( 0.00%) 43.4503 ( 13.39%)
Amean 240 50.1110 ( 0.00%) 44.4660 ( 11.26%)
Stddev 1 0.9714 ( 0.00%) 0.6617 ( 31.88%)
Stddev 4 0.4459 ( 0.00%) 0.2943 ( 34.01%)
Stddev 7 0.3091 ( 0.00%) 0.2722 ( 11.94%)
Stddev 12 0.4603 ( 0.00%) 0.1424 ( 69.05%)
Stddev 21 1.3647 ( 0.00%) 0.1566 ( 88.52%)
Stddev 30 4.1277 ( 0.00%) 0.0481 ( 98.84%)
Stddev 48 1.3689 ( 0.00%) 0.4968 ( 63.71%)
Stddev 79 2.0772 ( 0.00%) 0.5309 ( 74.44%)
Stddev 110 4.5655 ( 0.00%) 0.1846 ( 95.96%)
Stddev 141 4.2637 ( 0.00%) 0.6675 ( 84.34%)
Stddev 172 1.5741 ( 0.00%) 1.0242 ( 34.93%)
Stddev 203 1.0973 ( 0.00%) 1.4043 (-27.98%)
Stddev 234 2.2048 ( 0.00%) 0.8709 ( 60.50%)
Stddev 240 1.2849 ( 0.00%) 0.2688 ( 79.08%)