From: Al Stone <ahs3@redhat.com>
To: viresh.kumar@linaro.org, ashwin.chaugule@linaro.org, rjw@rjwysocki.net
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
Prashanth Prakash <pprakash@codeaurora.org>
Subject: Re: [PATCH v5] Force cppc_cpufreq to report values in KHz to fix user space reporting
Date: Mon, 1 Aug 2016 14:07:25 -0600 [thread overview]
Message-ID: <3ab83afa-1c91-4dcc-9206-a7a6dc3cfe83@redhat.com> (raw)
In-Reply-To: <1469049004-19069-1-git-send-email-ahs3@redhat.com>
On 07/20/2016 03:10 PM, Al Stone wrote:
> When CPPC is being used by ACPI on arm64, user space tools such as
> cpupower report CPU frequency values from sysfs that are incorrect.
>
> What the driver was doing was reporting the values given by ACPI tables
> in whatever scale was used to provide them. However, the ACPI spec
> defines the CPPC values as unitless abstract numbers. Internal kernel
> structures such as struct perf_cap, in contrast, expect these values
> to be in KHz. When these struct values get reported via sysfs, the
> user space tools also assume they are in KHz, causing them to report
> incorrect values (for example, reporting a CPU frequency of 1MHz when
> it should be 1.8GHz).
> [snip...]
Ping? If anyone has sent comments, I have not received them.
Thanks in advance for the time and effort. I know merge window can be
a very busy time.
--
ciao,
al
-----------------------------------
Al Stone
Software Engineer
Red Hat, Inc.
ahs3@redhat.com
-----------------------------------
next prev parent reply other threads:[~2016-08-01 20:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 21:10 Al Stone
2016-08-01 20:07 ` Al Stone [this message]
2016-08-01 20:31 ` Viresh Kumar
2016-08-11 18:15 ` Al Stone
2016-08-22 17:16 ` Al Stone
2016-08-22 17:45 ` Ashwin Chaugule
2016-08-22 18:12 ` Al Stone
2016-08-23 4:31 ` Pandruvada, Srinivas
2016-08-23 16:14 ` Al Stone
2016-08-25 22:00 ` Pandruvada, Srinivas
2016-08-30 17:09 ` Al Stone
2016-09-14 1:09 ` Rafael J. Wysocki
2016-09-19 18:53 ` Al Stone
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