[RFC PATCH 2/4] eal: allow applications to report their cpu utilization

[Robin Jarry]

Hi Morten,

Morten Brørup, Nov 23, 2022 at 12:52:
> This patch is based on a "gauge" (i.e. the busyness percentage) and an
> "interval" (i.e. the duration the gauge covers). I have to sample this
> gauge exactly every interval to collect data for a busyness chart. If
> the application's reporting interval is 1 second, I must sample the
> gauge every second, or statistical information will be lost.
>
> Instead, I would prefer the callback to return two counters:
> units_passed (e.g. number of cycles since application start) and
> units_busy (e.g. number of busy cycles since application start).
>
> I can sample these at any interval, and calculate the busyness of that
> interval as the difference: (units_busy - units_busy_before)
> / (units_passed - units_passed_before).
>
> If needed, I can also sample them at multiple intervals, e.g. every 1,
> 5 and 10 minutes, and expose in the "loadavg".
>
> I can also sample them every millisecond if I need to react quickly to
> a sudden increase/drop in busyness.

Your proposal makes a lot of sense and it will even be easier to
implement for applications. I'll do that for v2.

Thanks for the feedback.