On Thu, 21 Aug 2025 11:59:38 GMT, Jonas Norlinder <d...@openjdk.org> wrote:

>> Hi all,
>> 
>> This PR refactors the newly added GC CPU time code from 
>> [JDK-8359110](https://bugs.openjdk.org/browse/JDK-8359110).
>> 
>> As a stepping-stone to enable consolidation of CPU time tracking in e.g. 
>> hsperf counters and GCTraceCPUTime and to have a unified interface for 
>> tracking CPU time of various components in Hotspot this code can be 
>> refactored. This PR introduces a new interface to retrieve CPU time for 
>> various Hotspot components and it currently supports:
>> 
>> CPUTimeUsage::GC::total() // the sum of gc_threads(), vm_thread(), 
>> stringdedup()
>> 
>> CPUTimeUsage::GC::gc_threads()
>> CPUTimeUsage::GC::vm_thread()
>> CPUTimeUsage::GC::stringdedup()
>> 
>> 
>> I moved `CPUTimeUsage` to `src/hotspot/share/services` since it seemed 
>> fitting as it housed similar performance tracking code like 
>> `RuntimeService`, as this is no longer a class that is only specific to GC.
>> 
>> I also made a minor improvement in the CPU time logging during exit. Since 
>> `CPUTimeUsage` supports more components than just GC I changed the logging 
>> flag to from `gc,cpu` to `cpu` and created a detailed table:
>> 
>> 
>> [71.425s][info][cpu   ] === CPU time Statistics 
>> =============================================================
>> [71.425s][info][cpu   ]                                                      
>>                        CPUs
>> [71.425s][info][cpu   ]                                                      
>>           s       %  utilized
>> [71.425s][info][cpu   ]    Process
>> [71.425s][info][cpu   ]      Total                                           
>>   1616.3627  100.00      22.6
>> [71.425s][info][cpu   ]      Garbage Collection                              
>>     83.7322    5.18       1.2
>> [71.425s][info][cpu   ]        GC Threads                                    
>>     82.7671    5.12       1.2
>> [71.425s][info][cpu   ]        VM Thread                                     
>>      0.9651    0.06       0.0
>> [71.425s][info][cpu   ] 
>> =====================================================================================
>
> Jonas Norlinder has updated the pull request incrementally with one 
> additional commit since the last revision:
> 
>   Remove CPUTimeUsage::Runtime

@JonasNorlinder 
Your change (at version b7fdc0f8c608ecfdd6a4f6a875b8cd6a58ace5c8) is now ready 
to be sponsored by a Committer.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/26621#issuecomment-3210699903

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