RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v47]

[Jonathan Joo]

On Wed, 29 Nov 2023 15:23:55 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> We could add a new closure just used by GC that 's a sub-class of `ThreadTotalCPUTimeClosure` and just adds this to the constructor: 
>> 
>> instance->inc_gc_total_cpu_time(net_cpu_time);
>> 
>> 
>> That way we could get rid of `CPUTimeGroups::is_gc_counter()` as well since all those counters should use the "GC closure" or we can keep it and assert that no GC closure uses the wrong closure.
>> 
>> What do you think about that Albert, would that address your concerns?
>
> (I just realized that I made a typo in my previous msg; should be *callee* instead.) That is what I have in mind.
> 
> 
> void CPUTimeCounters::update_counter(name, total) {
>   auto counter = get_counter(name);
>   auto old_v = counter->get_value();
>   auto diff = total - old_v;
>   counter->inc(diff);
>   if (counter->is_gc_counter()) {
>     counter->inc(diff);
>   }
> }

I'm not sure I understood correctly, could you let me know if this latest commit addresses your comment in the way you were intending?

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PR Review Comment: https://git.openjdk.org/jdk/pull/15082#discussion_r1410059322