RE: [PATCH] tools/power turbostat: Fix Bzy_MHz calculation equation

From: Doug Smythies
Date: Thu Nov 02 2023 - 11:31:45 EST


Hi Peng and Wyes,

Just for your information about your recent "ping"s about your turbostat patches:

Please be aware that there is rarely any reply. There tends to be about 2 turbostat updates released per year. Your patches are in patchworks [1], as are some others, including an old one of mine from 2023.04.03
Eventually there will be an update, and hopefully it will include all our patches.

[1] https://patchwork.kernel.org/project/linux-pm/list/?series=&submitter=&state=&q=&archive=&delegate=107

... Doug

On 2023.10.29 08:12 Peng Liu wrote:

> Ping
>
> On 2023/10/7 13:46, Peng Liu wrote:
>> From: Peng Liu <liupeng17@xxxxxxxxxx>
>>
>> To calculate Bzy_MHz, TSC_delta should multiply APERF_delta instead
>> of dividing it.
>>
>> Signed-off-by: Peng Liu <liupeng17@xxxxxxxxxx>
>> ---
>> tools/power/x86/turbostat/turbostat.8 | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8
>> index 8f08c3fd498d..1ba6340d3b3d 100644
>> --- a/tools/power/x86/turbostat/turbostat.8
>> +++ b/tools/power/x86/turbostat/turbostat.8
>> @@ -370,7 +370,7 @@ below the processor's base frequency.
>>
>> Busy% = MPERF_delta/TSC_delta
>>
>> -Bzy_MHz = TSC_delta/APERF_delta/MPERF_delta/measurement_interval
>> +Bzy_MHz = TSC_delta*APERF_delta/MPERF_delta/measurement_interval
>>
>> Note that these calculations depend on TSC_delta, so they
>> are not reliable during intervals when TSC_MHz is not running at the base frequency.