Here are the results of a simple benchmark program (shown below) that I have run on a number of computers over time. It's a lousy program--for one thing, it's floating-point intensive, and I don't find floating point performance very interesting. Unfortunately, I can't go back in time with a better benchmark.
Machine OS and Compiler Seconds Core i7-4870HQ macOS 11.7.1 LLVM cc -O2 0.014 Pentium III-866 Win2000 MS C 12.00.8804 cl /Ox 0.218 Gateway G6-P180 NT MS C 11.00.7022 cl /Ox 0.991 Apex Pentium 133 NT MS C 11.00.7022 cl /Ox 1.331 SGI Challenge/L cc -O3 1.78 CYBER 2000 NOS/VE 1.8.3; Fortran scalar 1.889 IBM RS/6000-560: AIX 3.2.3? xlc -O 2.640 IBM RS/6000-560: AIX 3.2.3? f77 -O 3.160 IBM RS/6000-350 AIX 3.2.5 cc -O 3.60 i7-4870HQ + DtCyber Hustler FTN5 DO=LONG,OPT=2 5.0 IBM 3090-180 VM/SP HPO 4.2 opt(3) 5.8 Compaq ProLi 486/66 NT MS C 11.00.7022 cl /Ox 6.819 VAXstation 4000-60 FORTRAN /OPT 7.1 Gateway 4DX2-66/V NT MS For Powerstation 1.0 9.06 AMD64 3200+ DtCyber NOS 2.8.1 FTN OPT=2 9.698 Sun ELC f77 -cg89 -O4 pi.f 12.3 Sun ELC gcc -O4 13.6 VAX 8650 VMS 4.5 /opt/check=none 16.5 CDC 750 Hustler opt=3 18.0 Gateway 4DX2-66V NT; DOS For 5.1 fl /AL/FPi87/Ox 20.0 IBM 4381-1 VM/SP R. 4.0 opt(3) 46.5 MicroVAX II VMS 4.5 (default) 106.5 CDC 810 NOS/VE 1.2.1 opt=high 109.8 Sun 3/50 Unix -O -f68881 140.2Please note that the Desktop Cyber software emulator ran faster, on a modern PC, than the original Cyber 750!
Here is the original source to the benchmark program. It was written in FORTRAN because that was the language available on most of the machines I was testing at the time.
PROGRAM RANPI
c Program to compute PI by probability.
c By Mark Riordan 24-DEC-1986;
c Original version apparently by Don Shull.
c To be used as a CPU benchmark.
write(*,*) 'Starting PI...'
ztot = 0.0
low = 1
ixran = 1907
yran = 5813.0
ymult = 1307.0
ymod = 5471.0
itot = 1200000
DO 100 j=1,itot
c X and Y are two uniform random numbers between 0 and 1.
c They are computed using two linear congruential generators.
c A mix of integer and real arithmetic is used to simulate a
c real program. Magnitudes are kept small to prevent 32-bit
c integer overflow and to allow full precision even with a 23-bit
c mantissa.
iprod = 27611 * ixran
ixran = iprod - 74383*(iprod/74383)
x = float(ixran) / 74383.0
prod = ymult * yran
yran = (prod - ymod*int(prod/ymod))
y = yran / ymod
Z = X*x + Y*y
call myadd(ztot,z)
IF ( Z .LE. 1.0 ) THEN
low = low + 1
ENDIF
100 continue
write(*,9000) x,y,low,j
9000 format(' x=',f8.5,' y=',f8.5,' low=',i7,' j=',i7)
Pi = 4.0 * float(low)/float(Itot)
write(*,*) 'Pi = ',pi,' ztot = ',ztot,' itot = ',itot
STOP
END
subroutine myadd(sum,addend)
c Simple adding subroutine thrown in to allow subroutine
c calls/returns to be factored in as part of the benchmark.
sum = sum + addend
return
end
Here's the same program, hand-translated to C. Most of the more recent machines were run with this version.
/*--- pi.c PROGRAM RANPI
*
* Program to compute PI by probability.
* By Mark Riordan 24-DEC-1986;
* Original version apparently by Don Shull.
* To be used as a CPU benchmark.
*
* Translated to C from FORTRAN 20 Nov 1993
*/
#include <stdio.h>
void
myadd(float *sum,float *addend);
int
main(int argc, char *argv[]) {
float ztot, yran, ymult, ymod, x, y, z, pi, prod;
long int low, ixran, itot, j, iprod;
printf("Starting PI...\n");
ztot = 0.0;
low = 1;
ixran = 1907;
yran = 5813.0;
ymult = 1307.0;
ymod = 5471.0;
itot = 1200000;
for(j=1; j<=itot; j++) {
/*
c X and Y are two uniform random numbers between 0 and 1.
c They are computed using two linear congruential generators.
c A mix of integer and real arithmetic is used to simulate a
c real program. Magnitudes are kept small to prevent 32-bit
c integer overflow and to allow full precision even with a 23-bit
c mantissa.
*/
iprod = 27611 * ixran;
ixran = iprod - 74383*(long int)(iprod/74383);
x = (float)ixran / 74383.0;
prod = ymult * yran;
yran = (prod - ymod*(long int)(prod/ymod));
y = yran / ymod;
z = x*x + y*y;
myadd(&ztot,&z);
if ( z <= 1.0 ) {
low = low + 1;
}
}
printf(" x=%8.5f y=%8.5f low=%7d j=%7d\n",x,y,low,j);
pi = 4.0 * (float)low/(float)itot;
printf("Pi = %9.6f ztot=%12.2f itot=%8d\n",pi,ztot,itot);
return 0;
}
void
myadd(float *sum,float *addend) {
/*
c Simple adding subroutine thrown in to allow subroutine
c calls/returns to be factored in as part of the benchmark.
*/
*sum = *sum + *addend;
}