linux-kernel - Re: [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200717104314.GB2385870@google.com>
Date:   Fri, 17 Jul 2020 11:43:14 +0100
From:   Quentin Perret <qperret@...gle.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Daniel Kachhap <amit.kachhap@...il.com>,
        Javi Merino <javi.merino@...nel.org>,
        Amit Kucheria <amit.kucheria@...durent.com>,
        linux-kernel@...r.kernel.org, Rafael Wysocki <rjw@...ysocki.net>,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] thermal: cpufreq_cooling: Reuse effective_cpu_util()

On Friday 17 Jul 2020 at 11:33:05 (+0100), Quentin Perret wrote:
> On Friday 17 Jul 2020 at 11:14:38 (+0100), Quentin Perret wrote:
> > On Tuesday 14 Jul 2020 at 12:06:53 (+0530), Viresh Kumar wrote:
> > >  /**
> > > - * get_load() - get load for a cpu since last updated
> > > + * get_load() - get current load for a cpu
> > >   * @cpufreq_cdev:	&struct cpufreq_cooling_device for this cpu
> > >   * @cpu:	cpu number
> > > - * @cpu_idx:	index of the cpu in time_in_idle*
> > > + * @cpu_idx:	index of the cpu
> > >   *
> > > - * Return: The average load of cpu @cpu in percentage since this
> > > - * function was last called.
> > > + * Return: The current load of cpu @cpu in percentage.
> > >   */
> > >  static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
> > >  		    int cpu_idx)
> > >  {
> > > -	u32 load;
> > > -	u64 now, now_idle, delta_time, delta_idle;
> > > -	struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx];
> > > -
> > > -	now_idle = get_cpu_idle_time(cpu, &now, 0);
> > > -	delta_idle = now_idle - idle_time->time;
> > > -	delta_time = now - idle_time->timestamp;
> > > +	unsigned long util = cpu_util_cfs(cpu_rq(cpu));
> > > +	unsigned long max = arch_scale_cpu_capacity(cpu);
> > 
> > Should we subtract the thermal PELT signal from max?
> 
> Actually, that or add it the ENERGY_UTIL case in effective_cpu_util() as
> this appears to be missing for EAS too ...

Scratch that. I do think there is something missing in the EAS path, but
not sure that would fix it. I'll have a think and stop spamming
everybody in the meantime ...

The first question is still valid, though :)

Sorry for the noise,
Quentin