RFR: 8308633: Increase precision of timestamps in g1 log [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this improvement adding a digit to log timestamp to improve output. On modern machines, for some pauses, this can lead to sub-phase timings not adding up, and during development, extra work to evaluate different options.
> Also that rounding error starts to matter for e.g. pauses < a few ms. 
> 
> I am aware that there is a duplication of the timestamp format in the files, and this change did not improve that as this would be a different issue. Not sure where to put such a global constant though, any suggestions?
> 
> Testing: gha, looking at log files
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  Fix gtests

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14594/files
  - new: https://git.openjdk.org/jdk/pull/14594/files/b843f5b0..c311c530

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14594&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14594&range=00-01

  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/14594.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14594/head:pull/14594

PR: https://git.openjdk.org/jdk/pull/14594