Michael Galloway
out of curiosity, how can you measure the performance of individual cpus?
I ran the LINPACK benchmark in two xterm windows concurrently
(and had a third xterm window display the output from "top").
If I run one instance of linpack then every other time (on average)
it will run slowly. If I start two instances of linpack at the same
time, then one will run at full speed and the other at 1/10:th the
speed.
It's a pity that Linux "top" doesn't print which CPU a certain program
is running on like it does in Solaris. I also miss the Solaris
"psradm" program so I could have programmatically shut down one
of the CPUs at the time in order to try to pinpoint which of the
CPUs it is that is causing the problem...
XTERM WINDOW #1
-----------------------------------------------------------------------
[1] opteria:~/src/linpack> out/opteria/linpack.gcc
Rolled Double Precision Linpack
Size of REAL: 8 bytes
Array sizes: aa: 7812 Kbytes, a: 7820 Kbytes
norm. resid resid machep x[0]-1 x[n-1]-1
9.5 4.22017976e-12 2.22044605e-16 1.09912079e-13 5.08926234e-13
ttimes are reported for matrices of order 1000
dgefa dgesl total kflops unit ratio
ttimes for array with leading dimension of 1001
35.33 0.10 35.43 18873 0.11 632.68
31.39 0.00 31.39 21302 0.09 560.54
XTERM WINDOW #2
----------------------------------------------------------------------
[0] opteria:~/src/linpack> out/opteria/linpack.gcc
Rolled Double Precision Linpack
Size of REAL: 8 bytes
Array sizes: aa: 7812 Kbytes, a: 7820 Kbytes
norm. resid resid machep x[0]-1 x[n-1]-1
9.5 4.22017976e-12 2.22044605e-16 1.09912079e-13 5.08926234e-13
ttimes are reported for matrices of order 1000
dgefa dgesl total kflops unit ratio
ttimes for array with leading dimension of 1001
2.81 0.00 2.81 237960 0.01 50.18
2.81 0.01 2.82 237116 0.01 50.36
--
Peter Eriksson