oliveria@engin.umich.edu (ROQUE DONIZETE DE OLIVEIRA) (09/18/90)
How to correctly calculate cpu usage in fortran on the IBM RS/6000 ?
I tried the following program ( h.f ) :
C-----------------------------------------------------------------------
REAL*8 T , T1 , T2 , X
CALL TIME(T1)
X = 1.
DO 10 I=1,100000
X = X + 10.
10 CONTINUE
WRITE(6,50) X
50 FORMAT('X=',D14.7)
CALL TIME(T2)
T=T2 -T1
WRITE(6,100) T
100 FORMAT('T=',D14.7)
STOP
END
C-----------------------------------------------------------------------
SUBROUTINE TIME(T)
REAL*8 T
I1 = MCLOCK( )
T = 60*I1
RETURN
END
C-----------------------------------------------------------------------
xlf -o h.exe h.f
** main === End of Compilation 1 ===
** time === End of Compilation 2 ===
1501-510 Compilation successful for file h.f.
xanadu% h.exe
X= .1000001D+07
T= .4800000D+03
STOP
xanadu% time h.exe
X= .1000001D+07
T= .4200000D+03
STOP
1.8900u 1.1900s 0:00 91666% 0+0k 0+0io 0pf+0w
As you can see the output T=480 seconds is wrong (it took about a second
to run). It is probably a mistake in my sample program above. Can someone
point it out to me ? I wished ETIME was available in this system.
Thanks.
Roque Oliveira
oliveria@caen.engin.umich.edu