Allocations profiler

[Aleksey Shipilev]

On 02/20/2015 01:31 PM, Dawid Weiss wrote:
>> I am not sure how they are able to pull off low-overhead profiling like
>> that.
> 
> Just guessing but I think these may be separate problems (and separate
> benchmarks); if you're profiling memory allocations you don't care (or
> shouldn't look at) performance numbers.

I would think so too.

> I'm not saying it's easy to do or derive clear conclusions from
> numbers (considering TLABs, different GCs, local optimizations like
> escape analysis, etc.), but in many cases it's easy to spot relatively
> simple problems.

I agree. In the same way, you can "just" attach the sampling profiler
(like JFR, VisualVM, YourKit, you name it) and piggyback on the law of
large numbers. If there are allocations in the benchmark code, they will
float up.

What's a use case for allocation-accurate profiler?

-Aleksey.