EpsilonGC and throughput.

[Sergey Kuksenko]

Hi All,

Reading discussions about Epsilon GC and performance I'd rather warn you 
to do not mix latency and throughput.
I agree that it makes sense to talk about latency, but, please, don't 
expect that you will be able to achieve high throughput with Epsilon GC. 
Having zero barriers is not enough for this.
Just a simple example, I randomly took 9 standard throughput measuring 
benchmarks and compared Epsilon GC vs G1 and ParallelOld.

- EpsilonGC vs ParallelOld:
   -- only on 3 benchmarks overall throughput with Epsilon GC was higher 
than ParallelOld and speedup was : 0.2%-0.6%
   -- on 6 benchmarks, ParallelOld (with barriers and pauses) was faster 
(faster means throughput!), within 1%-10%.

- EpsilonGC vs G1
   -- EpsilonGC has shown higher throughput on 4 benchmarks, within 2%-3%
   -  G1 was faster on 5 benchmarks, within 2%-10%.

Compacting GCs have significant advantage over non-GC in terms of 
throughput (e.g. 
https://shipilev.net/jvm-anatomy-park/11-moving-gc-locality/)

-- 
Best regards,
Sergey Kuksenko