194989 - Use more efficient PRIntervalTime measurement on Mac OS X

Status: RESOLVED DUPLICATE of bug 757593

(NSPR :: NSPR, defect)

Description

[Simon Fraser [no longer active]]

Mac OS X currently uses gettimeofday() for measuring interval time units. This
is probably much slower than using UpTime(), or mach_absolute_time().

Comment 1

[Wan-Teh Chang]

Ideally we should read the "time base" in PowerPC processors.
We will need to make sure that threads running on different
processors in a multiprocessor system have a consistent interval
timer.

Comment 2

[Simon Fraser [no longer active]]

I think both UpTime() and mach_absolute_time() are using the CPU timebase. I'm
not sure what we need to do to ensure consistency between CPUs.

Comment 3

[Simon Fraser [no longer active]]

I've been informed (on the darwin mailing list) that mach_absolute_time() will
give consistent results on dual CPU systems. Things would be pretty hosed if it
didn't.

Comment 4

[Gabriele Svelto [:gsvelto]]

While looking around for time-related bugs I came across this (very old) one which has already been fixed so I'm closing it as a duplicate of the relevant bug.