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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Qian Cai <quic_qiancai@quicinc.com>
Cc: Ionela Voinescu <ionela.voinescu@arm.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rafael Wysocki <rjw@rjwysocki.net>,
	Ben Segall <bsegall@google.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>, Mel Gorman <mgorman@suse.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Will Deacon <will@kernel.org>,
	"open list:THERMAL" <linux-pm@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V3 0/4] cpufreq: cppc: Add support for frequency invariance
Date: Tue, 29 Jun 2021 10:15:27 +0530	[thread overview]
Message-ID: <20210629044527.puvaxcf5fxdly6tz@vireshk-i7> (raw)
In-Reply-To: <1f83d787-a796-0db3-3c2f-1ca616eb1979@quicinc.com>

On 25-06-21, 09:31, Qian Cai wrote:
> The problem is that all CPUs are never scaling down.
> "cpuinfo_cur_freq" and "scaling_cur_freq" are always the 2800 MHz on
> all CPUs on this idle system. This looks like a regression somewhere
> as in 5.4-based kernel, I can see "cpuinfo_cur_freq" can go down to
> 2000 MHz in the same scenario. I'll bisect a bit unless you have
> better ideas?

Few things which may let us understand the readings properly.

- cpuinfo_cur_freq: eventually makes a call to cppc_cpufreq_get_rate()
  and returns the *actual* frequency hardware is running at (based on
  counter diff around 2 us delay).

- scaling_cur_freq: is the frequency the cpufreq core thinks the
  hardware is running at, it would more in sync with what schedutil
  (or other governors) wants the CPU to run at. This can be different
  from what the hardware is running at, i.e. given by
  cpuinfo_cur_freq.

-- 
viresh

  parent reply	other threads:[~2021-06-29  4:45 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-21  9:19 [PATCH V3 0/4] cpufreq: cppc: Add support for frequency invariance Viresh Kumar
2021-06-21  9:19 ` [PATCH V3 1/4] cpufreq: cppc: Fix potential memleak in cppc_cpufreq_cpu_init Viresh Kumar
2021-06-23 13:44   ` Ionela Voinescu
2021-06-24  2:08     ` Viresh Kumar
2021-06-24  2:10   ` [PATCH V3.1 " Viresh Kumar
2021-06-25 10:33     ` Ionela Voinescu
2021-06-21  9:19 ` [PATCH V3 2/4] cpufreq: cppc: Pass structure instance by reference Viresh Kumar
2021-06-23 13:45   ` Ionela Voinescu
2021-06-24  2:22     ` Viresh Kumar
2021-06-25 10:30       ` Ionela Voinescu
2021-06-21  9:19 ` [PATCH V3 3/4] arch_topology: Avoid use-after-free for scale_freq_data Viresh Kumar
2021-06-23 13:50   ` Ionela Voinescu
2021-06-21  9:19 ` [PATCH V3 4/4] cpufreq: CPPC: Add support for frequency invariance Viresh Kumar
2021-06-24  9:48   ` Ionela Voinescu
2021-06-24 13:04     ` Viresh Kumar
2021-06-25  8:54       ` Ionela Voinescu
2021-06-25 16:54         ` Viresh Kumar
2021-06-28 10:49           ` Ionela Voinescu
2021-06-29  4:32             ` Viresh Kumar
2021-06-29  8:47               ` Ionela Voinescu
2021-06-29  8:53                 ` Viresh Kumar
2021-06-21 20:48 ` [PATCH V3 0/4] cpufreq: cppc: " Qian Cai
2021-06-22  6:52   ` Viresh Kumar
2021-06-23  4:16   ` Viresh Kumar
2021-06-23 12:57     ` Qian Cai
2021-06-24  2:54       ` Viresh Kumar
2021-06-24  9:49         ` Vincent Guittot
2021-06-24 10:48           ` Ionela Voinescu
2021-06-24 11:15             ` Vincent Guittot
2021-06-24 11:23               ` Ionela Voinescu
2021-06-24 11:59                 ` Vincent Guittot
2021-06-24 15:17             ` Qian Cai
2021-06-25 10:21               ` Ionela Voinescu
2021-06-25 13:31                 ` Qian Cai
2021-06-25 14:37                   ` Ionela Voinescu
2021-06-25 16:56                     ` Qian Cai
2021-06-26  2:29                     ` Qian Cai
2021-06-26 13:41                       ` Qian Cai
2021-06-29  4:55                         ` Viresh Kumar
2021-06-29  4:52                       ` Viresh Kumar
2021-06-29  9:06                       ` Ionela Voinescu
2021-06-29 13:38                         ` Qian Cai
2021-06-29  4:45                   ` Viresh Kumar [this message]
2021-06-24 20:44             ` Qian Cai
2021-06-28 11:54 ` Ionela Voinescu
2021-06-28 12:14   ` Vincent Guittot
2021-06-28 12:17     ` Vincent Guittot
2021-06-28 13:08     ` Ionela Voinescu
2021-06-28 21:37       ` Ionela Voinescu
2021-06-29  8:45         ` Vincent Guittot
2021-06-29  5:20   ` Viresh Kumar
2021-06-29  8:46     ` Ionela Voinescu

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