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author | 2017-10-06 09:23:24 +0200 | |
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committer | 2017-10-10 10:14:03 +0200 | |
commit | f2cdd9cc6c97e617b95f430f527a6e3165e1bee8 (patch) | |
tree | 6e2b49bc9382b9f6840592c5f3625e269787bac5 /kernel/sched | |
parent | sched/core: Fix wake_affine() performance regression (diff) | |
download | linux-f2cdd9cc6c97e617b95f430f527a6e3165e1bee8.tar.gz linux-f2cdd9cc6c97e617b95f430f527a6e3165e1bee8.tar.bz2 linux-f2cdd9cc6c97e617b95f430f527a6e3165e1bee8.zip |
sched/core: Address more wake_affine() regressions
The trivial wake_affine_idle() implementation is very good for a
number of workloads, but it comes apart at the moment there are no
idle CPUs left, IOW. the overloaded case.
hackbench:
NO_WA_WEIGHT WA_WEIGHT
hackbench-20 : 7.362717561 seconds 6.450509391 seconds
(win)
netperf:
NO_WA_WEIGHT WA_WEIGHT
TCP_SENDFILE-1 : Avg: 54524.6 Avg: 52224.3
TCP_SENDFILE-10 : Avg: 48185.2 Avg: 46504.3
TCP_SENDFILE-20 : Avg: 29031.2 Avg: 28610.3
TCP_SENDFILE-40 : Avg: 9819.72 Avg: 9253.12
TCP_SENDFILE-80 : Avg: 5355.3 Avg: 4687.4
TCP_STREAM-1 : Avg: 41448.3 Avg: 42254
TCP_STREAM-10 : Avg: 24123.2 Avg: 25847.9
TCP_STREAM-20 : Avg: 15834.5 Avg: 18374.4
TCP_STREAM-40 : Avg: 5583.91 Avg: 5599.57
TCP_STREAM-80 : Avg: 2329.66 Avg: 2726.41
TCP_RR-1 : Avg: 80473.5 Avg: 82638.8
TCP_RR-10 : Avg: 72660.5 Avg: 73265.1
TCP_RR-20 : Avg: 52607.1 Avg: 52634.5
TCP_RR-40 : Avg: 57199.2 Avg: 56302.3
TCP_RR-80 : Avg: 25330.3 Avg: 26867.9
UDP_RR-1 : Avg: 108266 Avg: 107844
UDP_RR-10 : Avg: 95480 Avg: 95245.2
UDP_RR-20 : Avg: 68770.8 Avg: 68673.7
UDP_RR-40 : Avg: 76231 Avg: 75419.1
UDP_RR-80 : Avg: 34578.3 Avg: 35639.1
UDP_STREAM-1 : Avg: 64684.3 Avg: 66606
UDP_STREAM-10 : Avg: 52701.2 Avg: 52959.5
UDP_STREAM-20 : Avg: 30376.4 Avg: 29704
UDP_STREAM-40 : Avg: 15685.8 Avg: 15266.5
UDP_STREAM-80 : Avg: 8415.13 Avg: 7388.97
(wins and losses)
sysbench:
NO_WA_WEIGHT WA_WEIGHT
sysbench-mysql-2 : 2135.17 per sec. 2142.51 per sec.
sysbench-mysql-5 : 4809.68 per sec. 4800.19 per sec.
sysbench-mysql-10 : 9158.59 per sec. 9157.05 per sec.
sysbench-mysql-20 : 14570.70 per sec. 14543.55 per sec.
sysbench-mysql-40 : 22130.56 per sec. 22184.82 per sec.
sysbench-mysql-80 : 20995.56 per sec. 21904.18 per sec.
sysbench-psql-2 : 1679.58 per sec. 1705.06 per sec.
sysbench-psql-5 : 3797.69 per sec. 3879.93 per sec.
sysbench-psql-10 : 7253.22 per sec. 7258.06 per sec.
sysbench-psql-20 : 11166.75 per sec. 11220.00 per sec.
sysbench-psql-40 : 17277.28 per sec. 17359.78 per sec.
sysbench-psql-80 : 17112.44 per sec. 17221.16 per sec.
(increase on the top end)
tbench:
NO_WA_WEIGHT
Throughput 685.211 MB/sec 2 clients 2 procs max_latency=0.123 ms
Throughput 1596.64 MB/sec 5 clients 5 procs max_latency=0.119 ms
Throughput 2985.47 MB/sec 10 clients 10 procs max_latency=0.262 ms
Throughput 4521.15 MB/sec 20 clients 20 procs max_latency=0.506 ms
Throughput 9438.1 MB/sec 40 clients 40 procs max_latency=2.052 ms
Throughput 8210.5 MB/sec 80 clients 80 procs max_latency=8.310 ms
WA_WEIGHT
Throughput 697.292 MB/sec 2 clients 2 procs max_latency=0.127 ms
Throughput 1596.48 MB/sec 5 clients 5 procs max_latency=0.080 ms
Throughput 2975.22 MB/sec 10 clients 10 procs max_latency=0.254 ms
Throughput 4575.14 MB/sec 20 clients 20 procs max_latency=0.502 ms
Throughput 9468.65 MB/sec 40 clients 40 procs max_latency=2.069 ms
Throughput 8631.73 MB/sec 80 clients 80 procs max_latency=8.605 ms
(increase on the top end)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/fair.c | 41 | ||||
-rw-r--r-- | kernel/sched/features.h | 2 |
2 files changed, 43 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 28cabed85387..ed2ab474ec93 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5363,6 +5363,10 @@ static int wake_wide(struct task_struct *p) * * wake_affine_idle() - only considers 'now', it check if the waking CPU is (or * will be) idle. + * + * wake_affine_weight() - considers the weight to reflect the average + * scheduling latency of the CPUs. This seems to work + * for the overloaded case. */ static bool @@ -5378,6 +5382,40 @@ wake_affine_idle(struct sched_domain *sd, struct task_struct *p, return false; } +static bool +wake_affine_weight(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int prev_cpu, int sync) +{ + s64 this_eff_load, prev_eff_load; + unsigned long task_load; + + this_eff_load = target_load(this_cpu, sd->wake_idx); + prev_eff_load = source_load(prev_cpu, sd->wake_idx); + + if (sync) { + unsigned long current_load = task_h_load(current); + + if (current_load > this_eff_load) + return true; + + this_eff_load -= current_load; + } + + task_load = task_h_load(p); + + this_eff_load += task_load; + if (sched_feat(WA_BIAS)) + this_eff_load *= 100; + this_eff_load *= capacity_of(prev_cpu); + + prev_eff_load -= task_load; + if (sched_feat(WA_BIAS)) + prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2; + prev_eff_load *= capacity_of(this_cpu); + + return this_eff_load <= prev_eff_load; +} + static int wake_affine(struct sched_domain *sd, struct task_struct *p, int prev_cpu, int sync) { @@ -5387,6 +5425,9 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, if (sched_feat(WA_IDLE) && !affine) affine = wake_affine_idle(sd, p, this_cpu, prev_cpu, sync); + if (sched_feat(WA_WEIGHT) && !affine) + affine = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync); + schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts); if (affine) { schedstat_inc(sd->ttwu_move_affine); diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 0a519f8c224d..319ed0e8a347 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -82,3 +82,5 @@ SCHED_FEAT(LB_MIN, false) SCHED_FEAT(ATTACH_AGE_LOAD, true) SCHED_FEAT(WA_IDLE, true) +SCHED_FEAT(WA_WEIGHT, true) +SCHED_FEAT(WA_BIAS, true) |