[gfortran] Implementation SYSTEM_CLOCK intrinsic subroutine

[Helge Avlesen]

Steve Kargl <sgk@troutmask.apl.washington.edu> writes:

| If you're timing single loops, then you want to use CPU_TIME(),
| which is a measure of CPU usage by the process.  

Hi,
yes sometimes that is what users want, but a high res wall clock timer
is also often advantageous - e.g. looking at I/O or in my case
communication times for OpenMP/MPI. IBM provides the rtc() function that
gives microsecond resolution that I use a lot. too me it looks like
the intent of the rather low level interface of system_clock is to be
the high res timer veichle of fortran.

Helge