From: Lukasz Luba <lukasz.luba@arm.com>
To: Quentin Perret <qperret@google.com>
Cc: nm@ti.com, juri.lelli@redhat.com, daniel.lezcano@linaro.org,
peterz@infradead.org, viresh.kumar@linaro.org,
dri-devel@lists.freedesktop.org, bjorn.andersson@linaro.org,
bsegall@google.com, alyssa.rosenzweig@collabora.com,
Morten.Rasmussen@arm.com, amit.kucheria@verdurent.com,
vincent.guittot@linaro.org, khilman@kernel.org,
agross@kernel.org, b.zolnierkie@samsung.com,
steven.price@arm.com, cw00.choi@samsung.com, mingo@redhat.com,
linux-imx@nxp.com, rui.zhang@intel.com, kernel-team@android.com,
mgorman@suse.de, linux-pm@vger.kernel.org,
linux-arm-msm@vger.kernel.org, s.hauer@pengutronix.de,
rostedt@goodmis.org, linux-mediatek@lists.infradead.org,
matthias.bgg@gmail.com, Chris.Redpath@arm.com,
linux-omap@vger.kernel.org, Dietmar.Eggemann@arm.com,
linux-arm-kernel@lists.infradead.org, airlied@linux.ie,
javi.merino@arm.com, tomeu.vizoso@collabora.com,
sboyd@kernel.org, shawnguo@kernel.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, kernel@pengutronix.de,
sudeep.holla@arm.com, ionela.voinescu@arm.com
Subject: Re: [PATCH 1/4] PM / EM: and devices to Energy Model
Date: Mon, 20 Jan 2020 14:52:07 +0000 [thread overview]
Message-ID: <40587d98-0e8d-cbac-dbf5-d26501d47a8c@arm.com> (raw)
In-Reply-To: <20200117105437.GA211774@google.com>
Hi Quentin,
On 1/17/20 10:54 AM, Quentin Perret wrote:
> Hey Lukasz,
>
> Still reading through this, but with small changes, this looks pretty
> good to me.
>
> On Thursday 16 Jan 2020 at 15:20:29 (+0000), lukasz.luba@arm.com wrote:
>> +int em_register_perf_domain(struct device *dev, unsigned int nr_states,
>> + struct em_data_callback *cb)
>> {
>> unsigned long cap, prev_cap = 0;
>> struct em_perf_domain *pd;
>> - int cpu, ret = 0;
>> + struct em_device *em_dev;
>> + cpumask_t *span = NULL;
>> + int cpu, ret;
>>
>> - if (!span || !nr_states || !cb)
>> + if (!dev || !nr_states || !cb || !cb->active_power)
>
> Nit: you check !cb->active_power in em_create_pd() too I think, so only
> one of the two is needed.
good point, thanks
>
>> return -EINVAL;
>>
>> - /*
>> - * Use a mutex to serialize the registration of performance domains and
>> - * let the driver-defined callback functions sleep.
>> - */
>> mutex_lock(&em_pd_mutex);
>>
>> - for_each_cpu(cpu, span) {
>> - /* Make sure we don't register again an existing domain. */
>> - if (READ_ONCE(per_cpu(em_data, cpu))) {
>> + if (_is_cpu_device(dev)) {
>> + span = kzalloc(cpumask_size(), GFP_KERNEL);
>> + if (!span) {
>> + mutex_unlock(&em_pd_mutex);
>> + return -ENOMEM;
>> + }
>> +
>> + ret = dev_pm_opp_get_sharing_cpus(dev, span);
>> + if (ret)
>> + goto free_cpumask;
>
> That I think should be changed. This creates some dependency on PM_OPP
> for the EM framework. And in fact, the reason we came up with PM_EM was
> precisely to not depend on PM_OPP which was deemed too Arm-specific.
>
> Suggested alternative: have two registration functions like so:
>
> int em_register_dev_pd(struct device *dev, unsigned int nr_states,
> struct em_data_callback *cb);
> int em_register_cpu_pd(cpumask_t *span, unsigned int nr_states,
> struct em_data_callback *cb);
Interesting, in the internal review Dietmar asked me to remove these two
functions. I had the same idea, which would simplify a bit the
registration and it does not need to check the dev->bus if it is CPU.
Unfortunately, we would need also two function in drivers/opp/of.c:
dev_pm_opp_of_register_cpu_em(policy->cpus);
and
dev_pm_opp_of_register_dev_em(dev);
Thus, I have created only one registration function, which you can see
in this patch set.
What do you think Dietmar?
>
> where em_register_cpu_pd() does the CPU-specific work and then calls
> em_register_dev_pd() (instead of having that big if (_is_cpu_device(dev))
> as you currently have). Would that work ?
Yes, I think you made a good point with this OPP dependency, which we
could avoid when we implement these two registration functions.
>
> Another possibility would be to query CPUFreq instead of PM_OPP to get
> the mask, but I'd need to look again at the driver registration path in
> CPUFreq to see if the policy masks have been populated when we enter
> PM_EM ... I am not sure if this is the case, but it's worth having a
> look too.
The policy mask is populated, our registration function is called at
the end of the init code of CPUfreq drivers. I will check this option.
>
> Thanks,
> Quentin
>
Thank you for your comments.
Regards,
Lukasz
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-01-20 17:09 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 15:20 [PATCH 0/4] Add support for devices in the Energy Model lukasz.luba
2020-01-16 15:20 ` [PATCH 1/4] PM / EM: and devices to " lukasz.luba
2020-01-17 10:54 ` Quentin Perret
2020-01-20 14:52 ` Lukasz Luba [this message]
2020-01-20 15:09 ` Quentin Perret
2020-01-20 18:27 ` Dietmar Eggemann
2020-01-20 18:38 ` Lukasz Luba
2020-01-21 9:10 ` Dietmar Eggemann
2020-01-21 9:37 ` Quentin Perret
2020-01-21 9:31 ` Quentin Perret
2020-01-20 14:53 ` Dietmar Eggemann
2020-01-20 15:11 ` Dietmar Eggemann
2020-01-20 15:36 ` Lukasz Luba
2020-01-20 15:27 ` Lukasz Luba
2020-01-20 15:28 ` Quentin Perret
2020-01-20 16:20 ` Lukasz Luba
2020-01-21 10:08 ` Quentin Perret
2020-01-21 10:49 ` Lukasz Luba
2020-01-16 15:20 ` [PATCH 2/4] OPP: change parameter to device pointer in dev_pm_opp_of_register_em() lukasz.luba
2020-01-16 15:20 ` [PATCH 3/4] thermal: devfreq_cooling: Refactor code and switch to use Energy Model lukasz.luba
2020-01-21 17:11 ` Steven Rostedt
2020-01-16 15:20 ` [PATCH 4/4] drm/panfrost: Register to the Energy Model with devfreq device lukasz.luba
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=40587d98-0e8d-cbac-dbf5-d26501d47a8c@arm.com \
--to=lukasz.luba@arm.com \
--cc=Chris.Redpath@arm.com \
--cc=Dietmar.Eggemann@arm.com \
--cc=Morten.Rasmussen@arm.com \
--cc=agross@kernel.org \
--cc=airlied@linux.ie \
--cc=alyssa.rosenzweig@collabora.com \
--cc=amit.kucheria@verdurent.com \
--cc=b.zolnierkie@samsung.com \
--cc=bjorn.andersson@linaro.org \
--cc=bsegall@google.com \
--cc=cw00.choi@samsung.com \
--cc=daniel.lezcano@linaro.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=ionela.voinescu@arm.com \
--cc=javi.merino@arm.com \
--cc=juri.lelli@redhat.com \
--cc=kernel-team@android.com \
--cc=kernel@pengutronix.de \
--cc=khilman@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-imx@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=linux-omap@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=matthias.bgg@gmail.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=nm@ti.com \
--cc=peterz@infradead.org \
--cc=qperret@google.com \
--cc=rjw@rjwysocki.net \
--cc=rostedt@goodmis.org \
--cc=rui.zhang@intel.com \
--cc=s.hauer@pengutronix.de \
--cc=sboyd@kernel.org \
--cc=shawnguo@kernel.org \
--cc=steven.price@arm.com \
--cc=sudeep.holla@arm.com \
--cc=tomeu.vizoso@collabora.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).