From: Lukasz Luba <lukasz.luba@arm.com>
To: Vincent Donnefort <vincent.donnefort@arm.com>,
Quentin Perret <qperret@google.com>
Cc: peterz@infradead.org, rjw@rjwysocki.net, viresh.kumar@linaro.org,
vincent.guittot@linaro.org, linux-kernel@vger.kernel.org,
ionela.voinescu@arm.com, dietmar.eggemann@arm.com
Subject: Re: [PATCH v2 3/3] PM / EM: Skip inefficient OPPs
Date: Tue, 25 May 2021 12:03:14 +0100 [thread overview]
Message-ID: <f8a2bbde-47c4-bd7d-96fa-228c9d9e2779@arm.com> (raw)
In-Reply-To: <20210525094601.GB369979@e124901.cambridge.arm.com>
On 5/25/21 10:46 AM, Vincent Donnefort wrote:
> On Tue, May 25, 2021 at 09:33:01AM +0000, Quentin Perret wrote:
>> On Friday 21 May 2021 at 17:54:24 (+0100), Vincent Donnefort wrote:
>>> @@ -161,6 +162,8 @@ static int em_create_perf_table(struct device *dev, struct em_perf_domain *pd,
>>> table[i].cost = div64_u64(fmax * table[i].power,
>>> table[i].frequency);
>>> if (table[i].cost >= prev_cost) {
>>> + table[i].flags = EM_PERF_STATE_INEFFICIENT;
>>> + pd->flags |= EM_PERF_DOMAIN_INEFFICIENCIES;
>>
>> If we're looking for micro-optimizations, then perhaps you could store
>> the index of the next efficient OPP (which would be 'i' if the current
>> OPP is already efficient), so you can jump to it directly when doing the
>> search.
>
> Wouldn't add any new field compared to this version so yeah might be an
> interesting improvement.
>
That's a few more instructions to parse the 'flags' filed. I'm not sure
if that brings speed improvements vs. if we not parse and have bool
filed with a simple looping. The out-of-order core might even suffer
from this parsing and loop index manipulations...
next prev parent reply other threads:[~2021-05-25 11:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 16:54 [PATCH v2 0/3] EM / PM: Inefficient OPPs Vincent Donnefort
2021-05-21 16:54 ` [PATCH v2 1/3] PM / EM: Fix inefficient state detection Vincent Donnefort
2021-05-24 12:41 ` Lukasz Luba
2021-05-25 9:50 ` Quentin Perret
2021-05-21 16:54 ` [PATCH v2 2/3] PM / EM: Extend em_perf_domain with a flag field Vincent Donnefort
2021-05-24 12:44 ` Lukasz Luba
2021-05-25 9:54 ` Quentin Perret
2021-05-21 16:54 ` [PATCH v2 3/3] PM / EM: Skip inefficient OPPs Vincent Donnefort
2021-05-24 12:55 ` Lukasz Luba
2021-05-25 8:48 ` Peter Zijlstra
2021-05-25 9:21 ` Vincent Donnefort
2021-05-25 10:00 ` Vincent Donnefort
2021-05-28 5:09 ` Viresh Kumar
2021-06-01 8:47 ` Vincent Donnefort
2021-06-01 8:56 ` Viresh Kumar
2021-06-01 9:07 ` Quentin Perret
2021-06-01 9:13 ` Viresh Kumar
2021-05-25 9:33 ` Quentin Perret
2021-05-25 9:46 ` Vincent Donnefort
2021-05-25 11:03 ` Lukasz Luba [this message]
2021-05-25 13:06 ` Quentin Perret
2021-05-25 13:34 ` Lukasz Luba
2021-05-25 9:47 ` Vincent Donnefort
2021-05-28 5:04 ` Viresh Kumar
2021-05-28 9:00 ` Lukasz Luba
2021-05-26 3:47 ` [PATCH v2 0/3] EM / PM: Inefficient OPPs Viresh Kumar
2021-05-26 8:56 ` Lukasz Luba
2021-05-26 9:33 ` Viresh Kumar
2021-05-27 7:13 ` Lukasz Luba
2021-05-26 9:01 ` Vincent Donnefort
2021-05-26 9:38 ` Viresh Kumar
2021-05-26 9:39 ` Viresh Kumar
2021-05-26 10:24 ` Lukasz Luba
2021-05-26 10:39 ` Lukasz Luba
2021-05-26 11:50 ` Lukasz Luba
2021-05-26 13:49 ` Vincent Donnefort
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f8a2bbde-47c4-bd7d-96fa-228c9d9e2779@arm.com \
--to=lukasz.luba@arm.com \
--cc=dietmar.eggemann@arm.com \
--cc=ionela.voinescu@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=qperret@google.com \
--cc=rjw@rjwysocki.net \
--cc=vincent.donnefort@arm.com \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).