NSPR logging timestamp format

I need to release NSPR 4.8 before May 20th.
The only open issue is the format of the timestamps
in NSPR log messages.  Please post your comments
in https://bugzilla.mozilla.org/show_bug.cgi?id=86396.

The current format is illustrated by the following
examples from Windows and Linux:

Windows example (note the actual precision is 15
milliseconds):

2009-04-12 21:38:11.323000 UTC - 0[9b33c8]: Loaded library Executable (init)
2009-04-12 21:38:11.323000 UTC - 57868[9bb438]: thread exiting
2009-04-12 21:38:11.323000 UTC - 124212[9bb098]: thread exiting
2009-04-12 21:38:11.323000 UTC - 58588[9bbb78]: thread exiting
2009-04-12 21:38:11.323000 UTC - 84644[9bb9f8]: thread exiting
2009-04-12 21:38:11.339000 UTC - 47348[9bb438]: thread exiting
2009-04-12 21:38:11.339000 UTC - 6112[9bb098]: thread exiting
2009-04-12 21:38:11.339000 UTC - 0[9b33c8]: PR_Cleanup: shutting down NSPR

Linux example (please ignore the bug that thread IDs are
printed as negative numbers):

2009-04-12 21:54:59.278954 UTC - -134628864[804b580]: Loaded library a.out (init
)
2009-04-12 21:54:59.285434 UTC - -134632528[8050640]: thread exiting
2009-04-12 21:54:59.285429 UTC - -143025232[8050768]: thread exiting
2009-04-12 21:54:59.291925 UTC - -159810640[80509b8]: thread exiting
2009-04-12 21:54:59.291999 UTC - -151417936[8050890]: thread exiting
2009-04-12 21:54:59.298288 UTC - -134632528[8050768]: thread exiting
2009-04-12 21:54:59.298354 UTC - -134628864[804b580]: PR_Cleanup:
shutting down NSPR
2009-04-12 21:54:59.298290 UTC - -143025232[8050640]: thread exiting

Please consider the following issues.

1. Calendar time (PR_Now) vs. interval time (PR_IntervalNow).

We use calendar time now, which is more human-readable but
may be more expensive (a system call).  One issue with
PR_IntervalNow is that it has a platform-dependent unit
(returned by PR_TicksPerSecond()) and it may wrap around
in about 12 hours.

2. Local time vs. UTC.

We use UTC now.

3. Sub-second resolution: milliseconds vs. microseconds.

We use microseconds now.  Using milliseconds saves
three characters per log message (which are all 0's on
Windows anyway) but some events may appear
simultaneous.

4. Delimiter: '-' vs. ':' (or even none)

We use '-' now.

Wan-Teh Chang