Le Wednesday 03 May 2017 à 20:00:28 (+0200), Peter Zijlstra a écrit :
>
[snip]
>
> Just FUDGE2 on its own seems to be the best on my system and is a change
> that makes sense (and something Paul recently pointed out as well).
>
> The implementation isn't particularly pretty or fast, but should
> illustrate the idea.
>
> Poking at the whole update_tg_cfs_load() thing only makes it worse after
> that. And while I agree that that code is mind bending; it seems to work
> OK-ish.
>
> Tejun, Vincent, could you guys have a poke?
I have added below patch on to of your:
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3191,7 +3191,7 @@ update_tg_cfs_load(struct cfs_rq *cfs_rq, struct
sched_entity *se)
}
}
} else {
- load = calc_cfs_shares(gcfs_rq, prop_type);
+ load = scale_load_down(calc_cfs_shares(gcfs_rq, prop_type));
}
delta = load - se->avg.load_avg;
--
The results for each configurations are :
** Config 1**
linaro@linaro-developer:~/schbench$cat /sys/module/fair/parameters/prop_type
1
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD NO_FUDGE NO_FUDGE2
Latency percentiles (usec)
50.0000th: 252
75.0000th: 346
90.0000th: 438
95.0000th: 485
*99.0000th: 537
99.5000th: 581
99.9000th: 5768
min=0, max=14202
** Config 2 **
linaro@linaro-developer:~/schbench$ cat /sys/module/fair/parameters/prop_type
1
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD FUDGE NO_FUDGE2
Latency percentiles (usec)
50.0000th: 261
75.0000th: 374
90.0000th: 457
95.0000th: 490
*99.0000th: 533
99.5000th: 585
99.9000th: 9392
min=0, max=13295
**Config 3**
linaro@linaro-developer:~/schbench$ cat /sys/module/fair/parameters/prop_type
1
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD NO_FUDGE FUDGE2
Latency percentiles (usec)
50.0000th: 233
75.0000th: 309
90.0000th: 456
95.0000th: 498
*99.0000th: 5272
99.5000th: 8184
99.9000th: 12368
min=0, max=14865
I have run several time the test, few were correct but most of them were like
above
**Config 4**
linaro@linaro-developer:~/schbench$ cat /sys/module/fair/parameters/prop_type
1
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD FUDGE FUDGE2
Latency percentiles (usec)
50.0000th: 211
75.0000th: 290
90.0000th: 380
95.0000th: 451
*99.0000th: 1778
99.5000th: 5048
99.9000th: 12752
min=0, max=15090
I have run several time the test, few were correct but most of them were like
above
** Config 5 **
linaro@linaro-developer:~/schbench$ cat /sys/module/fair/parameters/prop_type
0
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD FUDGE FUDGE2
Latency percentiles (usec)
50.0000th: 216
75.0000th: 297
90.0000th: 430
95.0000th: 487
*99.0000th: 2748
99.5000th: 7432
99.9000th: 12912
min=0, max=15046
I have run several time the test, few were correct but most of them were like
above
** Config 6 **
linaro@linaro-developer:~/schbench$ cat /sys/module/fair/parameters/prop_type
0
linaro@linaro-developer:~/schbench$ sudo cat /sys/kernel/debug/sched_features
GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY
WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE
NO_SIS_AVG_CPU RT_PUSH_IPI NO_FORCE_SD_OVERLAP RT_RUNTIME_SHARE NO_LB_MIN
ATTACH_AGE_LOAD FUDGE NO_FUDGE2
Latency percentiles (usec)
50.0000th: 245
75.0000th: 339
90.0000th: 444
95.0000th: 492
*99.0000th: 3036
99.5000th: 9104
99.9000th: 12496
min=0, max=14098
I have run several time the test, few were correct but most of them were like
above
Config 1 and 2 are the two configuraton which have stable and good results
Regards,
Vincent
