Contribution: Lock Contention Profiler for HotSpot

[Andrew Dinn]

On 04/11/16 12:04, Peter Hofer wrote:
   . . .
>> Have you measured the overhead this change produces when running with
>> contention detection disabled? (i.e. do we pay to have this feature even
>> when we don't use it).
> 
> We measured only the overhead relative to an unmodified OpenJDK build.
> 
> Our profiler observes only lock contention, which is generally handled
> via slow paths in the VM code, so this is where we added the code to
> record events. I don't expect this code to cause much overhead when
> disabled. However, we added fields to several data structures, which
> might make a difference.

Yes, increased footprint (in code as well as object space) would be as
much a concern as increased execution time.

> I'll run some more benchmarks and report my findings.

Thanks very much.

regards,


Andrew Dinn
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Senior Principal Software Engineer
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