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From: Shuah <shuah@kernel.org>
To: He Rongguang <herongguang@linux.alibaba.com>,
	trenn@suse.com, shuah@kernel.org, jwyatt@redhat.com,
	jkacur@redhat.com, wyes.karny@amd.com
Cc: linux-kernel@vger.kernel.org, shannon.zhao@linux.alibaba.com,
	linux-pm@vger.kernel.org
Subject: Re: [PATCH v3] cpupower: fix TSC MHz calculation
Date: Mon, 16 Dec 2024 14:00:54 -0700	[thread overview]
Message-ID: <5381389c-80bb-4c8d-9708-abc1aa9857ee@kernel.org> (raw)
In-Reply-To: <6084e3c9-921b-4450-97bd-51ec44c52c04@linux.alibaba.com>

On 12/11/24 19:14, He Rongguang wrote:
> Commit 'cpupower: Make TSC read per CPU for Mperf monitor' (c2adb1877b7)
> changes TSC counter reads per cpu, but left time diff global (from start
> of all cpus to end of all cpus), thus diff(time) is too large for a
> cpu's tsc counting, resulting in far less than acutal TSC_Mhz and thus
> `cpupower monitor` showing far less than actual cpu realtime frequency.
> 
> /proc/cpuinfo shows frequency:
> cat /proc/cpuinfo | egrep -e 'processor' -e 'MHz'
> ...
> processor : 171
> cpu MHz   : 4108.498
> ...
> 
> before fix (System 100% busy):
>      | Mperf              || Idle_Stats
>   CPU| C0   | Cx   | Freq  || POLL | C1   | C2
>   171|  0.77| 99.23|  2279||  0.00|  0.00|  0.00
> 
> after fix (System 100% busy):
>      | Mperf              || Idle_Stats
>   CPU| C0   | Cx   | Freq  || POLL | C1   | C2
>   171|  0.46| 99.54|  4095||  0.00|  0.00|  0.00
> 
> Fixes: c2adb1877b76 ("cpupower: Make TSC read per CPU for Mperf monitor")
> Signed-off-by: He Rongguang <herongguang@linux.alibaba.com>
> ---

Applied to
https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux.git/log/?h=cpupower
to be included in my next pull request to Rafael.

thanks,
-- Shuah

      reply	other threads:[~2024-12-16 21:00 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-12  2:14 He Rongguang
2024-12-16 21:00 ` Shuah [this message]

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