RFR (S): 8245088: Always provide logs for G1 heap expansion calculations

[stefan.johansson at oracle.com]

Hi Thomas,

On 2020-05-18 10:23, Thomas Schatzl wrote:
> Hi all,
> 
>    I would like the heap ergonomics code which determines by what amount 
> to expand to always print internal state, not only on changes.
> 
> Since heap expansion is based on long term (and short term) application 
> behavior, getting only information when something happened is too late 
> to understand the results.
> 
> The gc+ergo+heap=debug log message has also been changed to include all 
> interesting information; there is a new trace level message that tracks 
> our low-pass filter.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8245088
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8245088/webrev/
Looks good, apart from the clamp on line 179. It should be:
clamp(expand_bytes, min_expand_bytes, uncommitted_bytes)

Thanks,
Stefan

> Testing:
> hs-tier1-5
> 
> Thanks,
>    Thomas