This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]

Re: Performance measurements


Den 24-Jun-98 10:51:03 skrev Martin Kahlert fĝlgende 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,

/ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻTŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ\
| Rask Ingemann Lambertsen       | E-mail: mailto:rask@kampsax.k-net.dk  |
| Registered Phase5 developer    | WWW: http://www.gbar.dtu.dk/~c948374/ |
| A4000, 775 kkeys/s (RC5-64)    | "ThrustMe" on XPilot, ARCnet and IRC  |
|                           LOAD "emacs",8,1                             |



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]