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Message-ID: <5381389c-80bb-4c8d-9708-abc1aa9857ee@kernel.org>
Date: Mon, 16 Dec 2024 14:00:54 -0700
From: Shuah <shuah@...nel.org>
To: He Rongguang <herongguang@...ux.alibaba.com>, trenn@...e.com,
shuah@...nel.org, jwyatt@...hat.com, jkacur@...hat.com, wyes.karny@....com
Cc: linux-kernel@...r.kernel.org, shannon.zhao@...ux.alibaba.com,
linux-pm@...r.kernel.org
Subject: Re: [PATCH v3] cpupower: fix TSC MHz calculation
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@...ux.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
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