Re: [PATCH v2] cpupower : Fix cpupower working when cpu0 is offline

[Shuah Khan]

On 11/07/2017 01:58 AM, Abhishek wrote:
> Hi,
> 
> Can you have a look at it?
> 
> Thanks and Regards,
> 
> Abhishek Goel
> 
> System Engineer
> 
> IBM India Pvt. Ltd.
> 

Please refrain from top posting on kernel email thread.
In-lining comments and bottom posting is the norm.

> 
> On 11/07/2017 12:50 PM, Abhishek Goel wrote:
>> cpuidle_monitor used to assume that cpu0 is always online which is not
>> a valid assumption on POWER machines. This patch fixes this by searching
>> for the first online cpu and uses it, instead of always using cpu0 for
>> monitoring which may not be online.
>>
>> Signed-off-by: Abhishek Goel <huntbag@xxxxxxxxxxxxxxxxxx>
>> ---
>> v2: Commit message updated.
>> ---
>> Â tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c | 14 +++++++++++---
>> Â 1 file changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
>> index 1b5da00..adacf99 100644
>> --- a/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
>> +++ b/tools/power/cpupower/utils/idle_monitor/cpuidle_sysfs.c
>> @@ -130,15 +130,23 @@ static struct cpuidle_monitor *cpuidle_register(void)
>> Â {
>> ÂÂÂÂÂ int num;
>> ÂÂÂÂÂ char *tmp;
>> +ÂÂÂ int first_online_cpu;
>> +
>> +ÂÂÂ for (num = 0; num < cpu_count; num++) {
>> +ÂÂÂÂÂÂÂ if (cpupower_is_cpu_online(num))
>> +ÂÂÂÂÂÂÂÂÂÂÂ break;
>> +ÂÂÂ };
>> +ÂÂÂ first_online_cpu = num;

Isn't it simpler to use sched_getcpu()n instead and use that instead
of walking the sysfs nodes since assumption is made that the idle state
count is the same for all CPUs

>>
>> ÂÂÂÂÂ /* Assume idle state count is the same for all CPUs */
>> -ÂÂÂ cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(0);

This simply be:

cpuidle_sysfs_monitor.hw_states_num = cpuidle_state_count(sched_getcpu);

>> +ÂÂÂ cpuidle_sysfs_monitor.hw_states_num =
>> +ÂÂÂÂÂÂÂ cpuidle_state_count(first_online_cpu);
>>
>> ÂÂÂÂÂ if (cpuidle_sysfs_monitor.hw_states_num <= 0)
>> ÂÂÂÂÂÂÂÂÂ return NULL;
>>
>> ÂÂÂÂÂ for (num = 0; num < cpuidle_sysfs_monitor.hw_states_num; num++) {
>> -ÂÂÂÂÂÂÂ tmp = cpuidle_state_name(0, num);
>> +ÂÂÂÂÂÂÂ tmp = cpuidle_state_name(first_online_cpu, num);
>> ÂÂÂÂÂÂÂÂÂ if (tmp == NULL)
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂ continue;
>>
>> @@ -146,7 +154,7 @@ static struct cpuidle_monitor *cpuidle_register(void)
>> ÂÂÂÂÂÂÂÂÂ strncpy(cpuidle_cstates[num].name, tmp, CSTATE_NAME_LEN - 1);
>> ÂÂÂÂÂÂÂÂÂ free(tmp);
>>
>> -ÂÂÂÂÂÂÂ tmp = cpuidle_state_desc(0, num);
>> +ÂÂÂÂÂÂÂ tmp = cpuidle_state_desc(first_online_cpu, num);
>> ÂÂÂÂÂÂÂÂÂ if (tmp == NULL)
>> ÂÂÂÂÂÂÂÂÂÂÂÂÂ continue;
>> ÂÂÂÂÂÂÂÂÂ strncpy(cpuidle_cstates[num].desc, tmp,ÂÂÂ CSTATE_DESC_LEN - 1);
> 

thanks,
-- Shuah