by I have a dual Pentium Pro machine from TriStar with 128MB ram. I
installed Red Hat 4.2 and built a SMP kernel, which finds the second
processor -- I can see it in /proc. I've been benchmarking this machine
against a Linux/Alpha, DEC/Alpha and SGI IRIX system. We are running
FORTRAN code - I'm using g77 to compile on the dual Ppro and timing using
/usr/bin/time program
I'm getting system times that are incredibly large on this system as
compared to any of the other machines, as well as single processor Intel
machines. If the system time was 1/10th of the user time, it would be
OK -- the machine would be fast, but under certain compilations, the
system time is even larger than the user time. Anyone know anything about
this ? Below are some sample timings:
compiler options user time system time
No options 24.71 106.17
-O2 28.67 45.25
-O2 -ffast-math 15.43 12.68
-O2 -ffast-math -funroll-loops 22.43 9.78
-O4 -ffast-math -funroll-loops 17.46 10.65
On other machines, system times are typically less than 1 sec (the above
units).
Dirk