linux-kernel - Re: [PATCH v2] cpupower: Provide online and offline CPU information

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Message-ID: <6694193a-f44e-1239-26c2-7e01650964fc@linuxfoundation.org>
Date:   Fri, 2 Oct 2020 11:27:51 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Brahadambal Srinivasan <latha@...ux.vnet.ibm.com>,
        shuah@...nel.org, trenn@...e.com
Cc:     Janakarajan.Natarajan@....com, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Pavithra R . Prakash" <pavrampu@...ibm.com>,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH v2] cpupower: Provide online and offline CPU information

On 9/29/20 7:11 AM, Brahadambal Srinivasan wrote:
> When a user tries to modify cpuidle or cpufreq properties on offline
> CPUs, the tool returns success (exit status 0) but also does not provide
> any warning message regarding offline cpus that may have been specified
> but left unchanged. In case of all or a few CPUs being offline, it can be
> difficult to keep track of which CPUs didn't get the new frequency or idle
> state set. Silent failures are difficult to keep track of when there are a
> huge number of CPUs on which the action is performed.
> 
> This patch adds helper functions to find both online and offline CPUs and
> print them out accordingly.
> 
> We use these helper functions in cpuidle-set and cpufreq-set to print an
> additional message if the user attempts to modify offline cpus.
> 
> Reported-by: Pavithra R. Prakash <pavrampu@...ibm.com>
> Signed-off-by: Brahadambal Srinivasan <latha@...ux.vnet.ibm.com>
> ---
>   tools/power/cpupower/utils/cpufreq-set.c     |  3 +
>   tools/power/cpupower/utils/cpuidle-set.c     |  4 ++
>   tools/power/cpupower/utils/cpupower.c        |  8 +++
>   tools/power/cpupower/utils/helpers/helpers.h | 12 ++++
>   tools/power/cpupower/utils/helpers/misc.c    | 66 +++++++++++++++++++-
>   5 files changed, 92 insertions(+), 1 deletion(-)
> 

Please elaborate the changes made since v1.

I am seeing compile warnings. Please fix and send v3.

utils/cpufreq-set.c: In function ‘cmd_freq_set’:
utils/cpufreq-set.c:332:2: warning: implicit declaration of function 
‘print_offline_cpus’ [-Wimplicit-function-declaration]
   332 |  print_offline_cpus();
       |  ^~~~~~~~~~~~~~~~~~
   CC       utils/cpupower-set.o
   CC       utils/cpupower-info.o
   CC       utils/cpuidle-info.o
   CC       utils/cpuidle-set.o
utils/cpuidle-set.c: In function ‘cmd_idle_set’:
utils/cpuidle-set.c:187:2: warning: implicit declaration of function 
‘print_offline_cpus’ [-Wimplicit-function-declaration]
   187 |  print_offline_cpus();

thanks,
-- Shuah