Re: Performance measurements

["Rask Ingemann Lambertsen" <rask@kampsax.k-net.dk>]

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Den 24-Jun-98 10:51:03 skrev Martin Kahlert følgende om "Performance measurements":
> Hi,
> i tried to compare different compilers on my numerical code.
> Therefore i extracted a FPU intensive function and surrounded
> it with a loop while measuring the execution time.

It is also very memcpy() intensive. If your C library's memcpy() isn't very
good, you can gain quite some performance. I went from 34 MFLOPS to 59 MFLOPS
just by optimizing memcpy().

Here are some PowerPC 604e, 200 MHz results:

AmigaOS:
gcc version egcs-2.90.23 980102 (egcs-1.0.1 release)
-DPI=M_PI -O3 -fomit-frame-pointer -mcpu=604 -mmultiple -mstring
59.28 MFLOPS

AmigaOS:
gcc version 2.7.2.1
-DPI=M_PI -O3 -fomit-frame-pointer -mcpu=604 -mmultiple -mstring
54.15 MFLOPS

AIX (RS6000 43P):
gcc version 2.6.3
-DPI=M_PI -O3 -fomit-frame-pointer -mcpu=604 -Wa,-m604
54.68 MFLOPS

AIX (RS6000 43P):
Vendor supplied cc
-DPI=M_PI -O3 -qstrict
63.28 MFLOPS

AIX (RS6000 43P):
Vendor supplied cc
-DPI=M_PI -O3 -qstrict -qarch=ppc -qtune=604
60.89 MFLOPS

(?)

At least the performance is heading in the right direction, but it looks on
the low side low to me. Perhaps someone with a more recent PowerPC EGCS
build could be persuaded to post some results?

Regards,

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