RFR: 8351925: JFR: Microsecond time format precision for JFR tool

[Erik Gahlin]

On Wed, 26 Mar 2025 15:44:15 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> I do see folks in my vicinity (myself included) reaching for human-readable output for quick and dirty analysis. Very often that human-readable output is really great to quickly capture what is going on. At the scales we operate on, it is useful to see microseconds to correlate events happening within a millisecond. Switching to JSON does work, but it feels like an unnecessary friction.
> 
> Microsecond precision for timings is not uncommon. For example, Linux perf tools routinely report ISO 8601 timestamps with microsecond precision.

The output from PrettyWriter is used by RecordedEvent::toString(), so it serves more than one purpose. What is the primary friction you see in --json? The verbose stack traces, too much precision, or the need to specify a command-line flag?

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PR Comment: https://git.openjdk.org/jdk/pull/24029#issuecomment-2765870818