Question: DURATION

[liudongmiao]

Currently, the DURATION is using CLOCK_PROCESS_CPUTIME_ID since 2015, introduced in commit a4cf218.

For time, nginx switch to CLOCK_MONOTONIC / CLOCK_MONOTONIC_FAST since 2018.

For openjdk, nanoTime using CLOCK_MONOTONIC. For macOS, openjdk use mach_absolute_time and mach_timebase_info, however, CLOCK_MONOTONIC is available to.

Would it ok to switch CLOCK_MONOTONIC?

[liudongmiao]

@zimmerle is the original author of this. And @martinhsv is very active for this project.

[liudongmiao]

However, DURATION returns seconds, cannot be used for performance time.

[liudongmiao]

#1011 for related perf_*

[martinhsv]

However, DURATION returns seconds, cannot be used for performance time.

I don't understand that comment.

DURATION is implemented as a variable of type double, which means it can and will return a number like 0.024000 indicating 24 milliseconds -- or 1.315 indicating 1315 milliseconds.

[liudongmiao]

Sorry for the double.