From: Quentin Perret <quentin.perret@arm.com>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, rjw@rjwysocki.net,
juri.lelli@redhat.com, dietmar.eggemann@arm.com,
Morten.Rasmussen@arm.com, viresh.kumar@linaro.org,
valentin.schneider@arm.com
Subject: Re: [PATCH v5 01/10] sched/pelt: Move pelt related code in a dedicated file
Date: Tue, 29 May 2018 15:55:06 +0100 [thread overview]
Message-ID: <20180529145506.GF15173@e108498-lin.cambridge.arm.com> (raw)
In-Reply-To: <20180525180455.GF30654@e110439-lin>
On Friday 25 May 2018 at 19:04:55 (+0100), Patrick Bellasi wrote:
> On 25-May 15:26, Quentin Perret wrote:
> > And also, I understand these functions are large, but if we _really_
> > want to inline them even though they're big, why not putting them in
> > sched-pelt.h ?
>
> Had the same tought at first... but then I recalled that header is
> generated from a script. Thus, eventually, it should be a different one.
Ah, good point. This patch already introduces a pelt.h so I guess that
could work as well.
>
> > We probably wouldn't accept that for everything, but
> > those PELT functions are used all over the place, including latency
> > sensitive code paths (e.g. task wake-up).
>
> We should better measure the overheads, if any, and check what
> (a modern) compiler does. Maybe some hackbench run could help on the
> first point.
FWIW, I ran a few hackbench tests today on my Intel box:
- Intel i7-6700 (4 cores / 8 threads) @ 3.40GHz
- Base kernel: today's tip/sched/core "2539fc82aa9b sched/fair: Update
util_est before updating schedutil"
- Compiler: GCC 7.3.0
The tables below summarize the results for:
perf stat --repeat 10 perf bench sched messaging --pipe --thread -l 50000 --group G
Without patch:
+---+-------+----------+---------+
| G | Tasks | Duration | Stddev |
+---+-------+----------+---------+
| 1 | 40 | 3.906 | +-0.84% |
| 2 | 80 | 8.569 | +-0.77% |
| 4 | 160 | 16.384 | +-0.46% |
| 8 | 320 | 33.686 | +-0.42% |
+---+-------+----------+---------+
With patch:
+---+-------+----------------+---------+
| G | Tasks | Duration | Stddev |
+---+-------+----------------+---------+
| 1 | 40 | 3.953 (+1.2%) | +-1.43% |
| 2 | 80 | 8.646 (+0.9%) | +-0.32% |
| 4 | 160 | 16.390 (+0.0%) | +-0.38% |
| 8 | 320 | 33.992 (+0.9%) | +-0.27% |
+---+-------+----------------+---------+
So there is (maybe) a little something on my box, but not so significant
IMHO ... :)
Thanks,
Quentin
next prev parent reply other threads:[~2018-05-29 14:55 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 13:12 [PATCH v5 00/10] track CPU utilization Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 01/10] sched/pelt: Move pelt related code in a dedicated file Vincent Guittot
2018-05-25 14:26 ` Quentin Perret
2018-05-25 16:14 ` Peter Zijlstra
2018-05-29 8:21 ` Quentin Perret
2018-05-25 18:04 ` Patrick Bellasi
2018-05-29 14:55 ` Quentin Perret [this message]
2018-05-29 15:02 ` Vincent Guittot
2018-05-29 15:04 ` Quentin Perret
2018-05-25 13:12 ` [PATCH v5 02/10] sched/rt: add rt_rq utilization tracking Vincent Guittot
2018-05-25 15:54 ` Patrick Bellasi
2018-05-29 13:29 ` Vincent Guittot
2018-05-30 9:32 ` Patrick Bellasi
2018-05-30 10:06 ` Vincent Guittot
2018-05-30 11:01 ` Patrick Bellasi
2018-05-30 14:39 ` Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 03/10] cpufreq/schedutil: add rt " Vincent Guittot
2018-05-30 7:03 ` Viresh Kumar
2018-05-30 8:23 ` Vincent Guittot
2018-05-30 9:40 ` Patrick Bellasi
2018-05-30 9:53 ` Vincent Guittot
2018-05-30 16:46 ` Quentin Perret
2018-05-31 8:46 ` Juri Lelli
2018-06-01 16:23 ` Peter Zijlstra
2018-06-01 17:23 ` Patrick Bellasi
2018-06-04 10:17 ` Quentin Perret
2018-06-04 15:16 ` Patrick Bellasi
2018-05-25 13:12 ` [PATCH v5 04/10] sched/dl: add dl_rq " Vincent Guittot
2018-05-30 10:50 ` Patrick Bellasi
2018-05-30 11:51 ` Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 05/10] cpufreq/schedutil: get max utilization Vincent Guittot
2018-05-28 10:12 ` Juri Lelli
2018-05-28 14:57 ` Vincent Guittot
2018-05-28 15:22 ` Juri Lelli
2018-05-28 16:34 ` Vincent Guittot
2018-05-31 10:27 ` Patrick Bellasi
2018-05-31 13:02 ` Vincent Guittot
2018-06-01 13:53 ` Vincent Guittot
2018-06-01 17:45 ` Joel Fernandes
2018-06-04 6:41 ` Vincent Guittot
2018-06-04 7:04 ` Juri Lelli
2018-06-04 7:14 ` Vincent Guittot
2018-06-04 10:12 ` Juri Lelli
2018-06-04 12:35 ` Vincent Guittot
2018-05-29 5:08 ` Joel Fernandes
2018-05-29 6:31 ` Juri Lelli
2018-05-29 6:48 ` Vincent Guittot
2018-05-29 9:47 ` Juri Lelli
2018-05-29 8:40 ` Quentin Perret
2018-05-29 9:52 ` Juri Lelli
2018-05-30 8:37 ` Quentin Perret
2018-05-30 8:51 ` Juri Lelli
2018-05-25 13:12 ` [PATCH v5 06/10] sched: remove rt and dl from sched_avg Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 07/10] sched/irq: add irq utilization tracking Vincent Guittot
2018-05-30 15:55 ` Dietmar Eggemann
2018-05-30 18:45 ` Vincent Guittot
2018-05-31 16:54 ` Dietmar Eggemann
2018-06-06 16:06 ` Vincent Guittot
2018-06-07 8:29 ` Dietmar Eggemann
2018-06-07 8:44 ` Vincent Guittot
2018-06-07 9:06 ` Dietmar Eggemann
2018-05-25 13:12 ` [PATCH v5 08/10] cpufreq/schedutil: take into account interrupt Vincent Guittot
2018-05-28 10:41 ` Juri Lelli
2018-05-28 12:06 ` Vincent Guittot
2018-05-28 12:37 ` Juri Lelli
2018-05-25 13:12 ` [PATCH v5 09/10] sched: remove rt_avg code Vincent Guittot
2018-05-25 13:12 ` [PATCH v5 10/10] proc/sched: remove unused sched_time_avg_ms Vincent Guittot
2018-06-04 16:50 ` [PATCH v5 00/10] track CPU utilization Peter Zijlstra
2018-06-04 17:13 ` Quentin Perret
2018-06-04 18:08 ` Vincent Guittot
2018-06-05 14:18 ` Peter Zijlstra
2018-06-05 15:03 ` Juri Lelli
2018-06-05 15:38 ` Patrick Bellasi
2018-06-05 22:27 ` Peter Zijlstra
2018-06-06 9:44 ` Quentin Perret
2018-06-06 9:59 ` Vincent Guittot
2018-06-06 10:02 ` Vincent Guittot
2018-06-06 10:12 ` Quentin Perret
2018-06-05 8:36 ` Vincent Guittot
2018-06-05 10:57 ` Quentin Perret
2018-06-05 11:59 ` Vincent Guittot
2018-06-05 13:12 ` Quentin Perret
2018-06-05 13:18 ` Vincent Guittot
2018-06-05 13:52 ` Quentin Perret
2018-06-05 13:55 ` Vincent Guittot
2018-06-05 14:09 ` Quentin Perret
2018-06-05 14:21 ` Quentin Perret
2018-06-05 12:11 ` Juri Lelli
2018-06-05 13:05 ` Quentin Perret
2018-06-05 13:15 ` Juri Lelli
2018-06-05 14:01 ` Quentin Perret
2018-06-05 14:13 ` Juri Lelli
2018-06-06 13:05 ` Claudio Scordino
2018-06-06 13:20 ` Quentin Perret
2018-06-06 13:53 ` Claudio Scordino
2018-06-06 14:10 ` Quentin Perret
2018-06-06 21:05 ` luca abeni
2018-06-07 8:25 ` Quentin Perret
2018-06-06 20:53 ` luca abeni
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