From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <efault@gmx.de>
Cc: mingo@kernel.org, vincent.guittot@linaro.org,
linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
corbet@lwn.net, qyousef@layalina.io, chris.hyser@oracle.com,
patrick.bellasi@matbug.net, pjt@google.com, pavel@ucw.cz,
qperret@google.com, tim.c.chen@linux.intel.com,
joshdon@google.com, timj@gnu.org, kprateek.nayak@amd.com,
yu.c.chen@intel.com, youssefesmat@chromium.org,
joel@joelfernandes.org
Subject: Re: [PATCH 10/10] sched/fair: Implement an EEVDF like policy
Date: Thu, 9 Mar 2023 17:42:42 +0100 [thread overview]
Message-ID: <ZAoMgmMOYXBA4Mzs@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ZAn7QAjQvw5q6aI5@hirez.programming.kicks-ass.net>
On Thu, Mar 09, 2023 at 04:29:04PM +0100, Peter Zijlstra wrote:
> So if I add TICK_NSEC based sleeper bonus (/2 for gentle), then starve
> works -- this is the absolutely minimal amount required. It sucks a bit
> it's HZ dependent, but alas.
Fixes starve, sucks for schbench and hackbench :/
Clearly more thinking is required...
root@ivb-ep:~/bench# echo NO_FAIR_SLEEPERS > /debug/sched/features
root@ivb-ep:~/bench# ./doit-schbench.sh ; ./doit-hackbench-series.sh
Latency percentiles (usec)
50.0000th: 83
75.0000th: 102
90.0000th: 109
95.0000th: 114
*99.0000th: 450
99.5000th: 723
99.9000th: 985
min=0, max=1067
1: 0.55355 +- 0.00290 seconds time elapsed ( +- 0.52% )
2: 0.79591 +- 0.00545 seconds time elapsed ( +- 0.68% )
5: 1.5804 +- 0.0102 seconds time elapsed ( +- 0.65% )
10: 2.5674 +- 0.0110 seconds time elapsed ( +- 0.43% )
20: 4.6116 +- 0.0160 seconds time elapsed ( +- 0.35% )
40: 9.5965 +- 0.0167 seconds time elapsed ( +- 0.17% )
root@ivb-ep:~/bench# time taskset -c 3 ./starve/starve 1000000
expecting to receive 1000000 signals
^C
real 0m32.999s
user 0m0.000s
sys 0m0.719s
root@ivb-ep:~/bench# echo FAIR_SLEEPERS > /debug/sched/features
root@ivb-ep:~/bench# ./doit-schbench.sh ; ./doit-hackbench-series.sh
Latency percentiles (usec)
50.0000th: 87
75.0000th: 103
90.0000th: 111
95.0000th: 116
*99.0000th: 163
99.5000th: 697
99.9000th: 1110
min=0, max=1522
1: 0.59076 +- 0.00577 seconds time elapsed ( +- 0.98% )
2: 0.86093 +- 0.00407 seconds time elapsed ( +- 0.47% )
5: 2.1018 +- 0.0129 seconds time elapsed ( +- 0.61% )
10: 3.6378 +- 0.0395 seconds time elapsed ( +- 1.09% )
20: 5.56884 +- 0.00979 seconds time elapsed ( +- 0.18% )
40: 10.8570 +- 0.0207 seconds time elapsed ( +- 0.19% )
root@ivb-ep:~/bench# time taskset -c 3 ./starve/starve 1000000
expecting to receive 1000000 signals
real 0m5.651s
user 0m0.604s
sys 0m4.047s
---
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4938,17 +4938,22 @@ place_entity(struct cfs_rq *cfs_rq, stru
{
u64 vruntime = avg_vruntime(cfs_rq);
+ if (sched_feat(PRESERVE_LAG))
+ vruntime -= se->lag;
+
if (sched_feat(FAIR_SLEEPERS)) {
- u64 sleep_time;
+// u64 sleep_time;
/* sleeps up to a single latency don't count. */
if (!initial) {
- unsigned long thresh;
+ unsigned long thresh = TICK_NSEC;
- if (se_is_idle(se))
- thresh = sysctl_sched_min_granularity;
- else
- thresh = sysctl_sched_latency;
+ if (!sched_feat(EEVDF)) {
+ if (se_is_idle(se))
+ thresh = sysctl_sched_min_granularity;
+ else
+ thresh = sysctl_sched_latency;
+ }
/*
* Halve their sleep time's effect, to allow
@@ -4957,7 +4962,7 @@ place_entity(struct cfs_rq *cfs_rq, stru
if (sched_feat(GENTLE_FAIR_SLEEPERS))
thresh >>= 1;
- vruntime -= thresh;
+ vruntime -= calc_delta_fair(thresh, se);
}
/*
@@ -4966,15 +4971,12 @@ place_entity(struct cfs_rq *cfs_rq, stru
* slept for a long time, don't even try to compare its vruntime with
* the base as it may be too far off and the comparison may get
* inversed due to s64 overflow.
- */
sleep_time = rq_clock_task(rq_of(cfs_rq)) - se->exec_start;
if ((s64)sleep_time < 60LL * NSEC_PER_SEC)
+ */
vruntime = max_vruntime(se->vruntime, vruntime);
}
- if (sched_feat(PRESERVE_LAG))
- vruntime -= se->lag;
-
se->vruntime = vruntime;
set_slice(cfs_rq, se);
}
next prev parent reply other threads:[~2023-03-09 16:53 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 13:25 [PATCH 00/10] sched: EEVDF using latency-nice Peter Zijlstra
2023-03-06 13:25 ` [PATCH 01/10] sched: Introduce latency-nice as a per-task attribute Peter Zijlstra
2023-03-06 13:25 ` [PATCH 02/10] sched/core: Propagate parent tasks latency requirements to the child task Peter Zijlstra
2023-03-06 13:25 ` [PATCH 03/10] sched: Allow sched_{get,set}attr to change latency_nice of the task Peter Zijlstra
2023-03-06 13:25 ` [PATCH 04/10] sched/fair: Add latency_offset Peter Zijlstra
2023-03-06 13:25 ` [PATCH 05/10] sched/fair: Add sched group latency support Peter Zijlstra
2023-03-06 13:25 ` [PATCH 06/10] sched/fair: Add avg_vruntime Peter Zijlstra
2023-03-21 13:58 ` Chen Yu
2023-03-21 16:04 ` Peter Zijlstra
2023-03-24 7:12 ` Chen Yu
2023-03-24 10:03 ` Peter Zijlstra
2023-03-06 13:25 ` [PATCH 07/10] sched/fair: Remove START_DEBIT Peter Zijlstra
2023-03-06 13:25 ` [PATCH 08/10] sched/fair: Add lag based placement Peter Zijlstra
2023-03-16 22:49 ` Tim Chen
2023-03-06 13:25 ` [PATCH 09/10] rbtree: Add rb_add_augmented_cached() helper Peter Zijlstra
2023-03-06 13:25 ` [PATCH 10/10] sched/fair: Implement an EEVDF like policy Peter Zijlstra
2023-03-08 8:39 ` Mike Galbraith
2023-03-08 9:26 ` Mike Galbraith
2023-03-08 13:36 ` Mike Galbraith
2023-03-09 4:23 ` Mike Galbraith
2023-03-10 20:38 ` Peter Zijlstra
2023-03-11 5:53 ` Mike Galbraith
2023-03-11 7:56 ` Mike Galbraith
2023-03-09 9:06 ` Peter Zijlstra
2023-03-09 12:44 ` Peter Zijlstra
2023-03-09 15:29 ` Peter Zijlstra
2023-03-09 15:39 ` Peter Zijlstra
2023-03-09 16:24 ` Mike Galbraith
2023-03-09 16:42 ` Peter Zijlstra [this message]
2023-03-07 10:27 ` [PATCH 00/10] sched: EEVDF using latency-nice Vincent Guittot
2023-03-07 13:08 ` Peter Zijlstra
2023-03-08 15:13 ` Shrikanth Hegde
2023-03-22 6:49 ` K Prateek Nayak
2023-03-22 9:38 ` K Prateek Nayak
2023-03-23 11:53 ` Pavel Machek
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