Integrated: 8346568: G1: Other time can be negative
Sangheon Kim
sangheki at openjdk.org
Wed Apr 23 16:40:00 UTC 2025
On Fri, 4 Apr 2025 18:00:21 GMT, Sangheon Kim <sangheki at openjdk.org> wrote:
> Other time described in this bug is displayed at G1GCPhaseTimes::print_other(total_measured_time - sum_of_sub_phases). And the value can be negative for 3 reasons.
> 1. Different scope of measurement
> - 3 variables is out of scope from total_measured_time. Those used for wait-root-region-scan, verify-before/after.
> (_root_region_scan_wait_time_ms, _cur_verify_before_time_ms and _cur_verify_after_time_ms)
> - Changed not to be included in sum_of_sub_phases.
> - One may want to include them in total_measured_time but I think it is better to be addressed in a separate ticket.
> 2. Duplicated measurement
> - Initial and optional evacuation time include nmethod-cleanup-time, so separated them as we are already measuring them. As there is no public getter, just added cleanup time when those evacuation time are used internally.
> 3. Pre Concurrent task execution time
> - Sometimes the difference between the existing average time and pre-concurrent work is 2 digit milliseconds. Changed to measure exact time rather than accumulating the average value to sum_of_sub_phases and keep displaying concurrent tasks' average execution time.
>
> Testing: tier 1 ~ 5
This pull request has now been integrated.
Changeset: 8bd56452
Author: Sangheon Kim <sangheki at openjdk.org>
URL: https://git.openjdk.org/jdk/commit/8bd564521804e98911cc9ff3b7696165e3243139
Stats: 68 lines in 4 files changed: 36 ins; 20 del; 12 mod
8346568: G1: Other time can be negative
Reviewed-by: tschatzl, iwalulya
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PR: https://git.openjdk.org/jdk/pull/24454
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