RFR: JDK-8290868: NMT: MallocSiteTable statistics improvements

Fri Jul 22 18:52:30 UTC 2022

Smallish improvement/simplification for the MallocSiteTable statistics.

Instead of printing the full chain length distribution, which is not very helpful, we now print number of empty slots, medium bucket length, and max. bucket chain length. As a bonus, coding gets simpler.

Looks like this now:

thomas at starfish:~$ jcmd spring-petclinic VM.native_memory statistics
70863:
Native Memory Tracking Statistics:
...

Bucket chain length distribution:
unused:  1
longest: 15
median:  6

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Commit messages:
 - start

Changes: https://git.openjdk.org/jdk/pull/9611/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9611&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290868
  Stats: 41 lines in 1 file changed: 10 ins; 23 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/9611.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9611/head:pull/9611

PR: https://git.openjdk.org/jdk/pull/9611