From: Valentin Schneider <valentin.schneider@arm.com>
To: Beata Michalska <beata.michalska@arm.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
corbet@lwn.net, rdunlap@infradead.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH v5 2/3] sched/topology: Rework CPU capacity asymmetry detection
Date: Tue, 25 May 2021 10:53:07 +0100 [thread overview]
Message-ID: <87a6oj6sxo.mognet@arm.com> (raw)
In-Reply-To: <20210524225508.GA14880@e120325.cambridge.arm.com>
On 24/05/21 23:55, Beata Michalska wrote:
> On Mon, May 24, 2021 at 07:01:04PM +0100, Valentin Schneider wrote:
>> On 24/05/21 11:16, Beata Michalska wrote:
>> > This patch also removes the additional -dflags- parameter used when
>> ^^^^^^^^^^^^^^^^^^^^^^^
>> s/^/Also remove/
> I would kind of ... disagree.
> All the commit msg is constructed using passive structure, the suggestion
> would actually break that. And it does 'sound' bit imperative but I guess
> that is subjective. I'd rather stay with impersonal structure (which is
> applied through out the whole patchset).
It's mainly about the 'This patch' formulation, some take exception to that :-)
>>
>> > building sched domains as the asymmetry flags are now being set
>> > directly in sd_init.
>> >
>>
>> Few nits below, but beyond that:
>>
>> Tested-by: Valentin Schneider <valentin.schneider@arm.com>
>> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
>>
> Thanks a lot for the review and testing!
>
>> > +static inline int
>> > +asym_cpu_capacity_classify(struct sched_domain *sd,
>> > + const struct cpumask *cpu_map)
>> > +{
>> > + int sd_asym_flags = SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL;
>> > + struct asym_cap_data *entry;
>> > + int asym_cap_count = 0;
>> > +
>> > + if (list_is_singular(&asym_cap_list))
>> > + goto leave;
>> > +
>> > + list_for_each_entry(entry, &asym_cap_list, link) {
>> > + if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) {
>> > + ++asym_cap_count;
>> > + } else {
>> > + /*
>> > + * CPUs with given capacity might be offline
>> > + * so make sure this is not the case
>> > + */
>> > + if (cpumask_intersects(entry->cpu_mask, cpu_map)) {
>> > + sd_asym_flags &= ~SD_ASYM_CPUCAPACITY_FULL;
>> > + if (asym_cap_count > 1)
>> > + break;
>> > + }
>>
>> Readability nit: That could be made into an else if ().
> It could but then this way the -comment- gets more exposed.
> But that might be my personal perception so I can change that.
As always those are quite subjective! Methink something like this would
still draw attention to the offline case:
/*
* Count how many unique capacities this domain covers. If a
* capacity isn't covered, we need to check if any CPU with
* that capacity is actually online, otherwise it can be
* ignored.
*/
if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) {
++asym_cap_count;
} else if (cpumask_intersects(entry->cpu_mask, cpu_map)) {
sd_asym_flags &= ~SD_ASYM_CPUCAPACITY_FULL;
if (asym_cap_count > 1)
break;
}
next prev parent reply other threads:[~2021-05-25 9:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 10:16 [PATCH v5 0/3] Rework CPU capacity asymmetry detection Beata Michalska
2021-05-24 10:16 ` [PATCH v5 1/3] sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag Beata Michalska
2021-05-24 10:16 ` [PATCH v5 2/3] sched/topology: Rework CPU capacity asymmetry detection Beata Michalska
2021-05-24 18:01 ` Valentin Schneider
2021-05-24 22:55 ` Beata Michalska
2021-05-24 23:19 ` Beata Michalska
2021-05-25 9:53 ` Valentin Schneider [this message]
2021-05-25 10:29 ` Beata Michalska
2021-05-26 9:52 ` Dietmar Eggemann
2021-05-26 12:15 ` Beata Michalska
2021-05-26 12:51 ` Beata Michalska
2021-05-26 18:17 ` Dietmar Eggemann
2021-05-26 21:40 ` Beata Michalska
2021-05-27 15:08 ` Dietmar Eggemann
2021-05-27 17:07 ` Beata Michalska
2021-06-02 17:17 ` Dietmar Eggemann
2021-06-02 19:48 ` Beata Michalska
2021-06-03 9:09 ` Dietmar Eggemann
2021-06-03 9:24 ` Beata Michalska
2021-05-26 18:17 ` Dietmar Eggemann
2021-05-26 21:43 ` Beata Michalska
2021-05-27 7:03 ` Peter Zijlstra
2021-05-27 12:22 ` Dietmar Eggemann
2021-05-27 12:32 ` Beata Michalska
2021-05-25 8:25 ` Dietmar Eggemann
2021-05-25 9:30 ` Beata Michalska
2021-05-25 11:59 ` Dietmar Eggemann
2021-05-25 14:04 ` Beata Michalska
2021-05-24 10:16 ` [PATCH v5 3/3] sched/doc: Update the CPU capacity asymmetry bits Beata Michalska
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