Hi,
Following up to my previous message...here's some results for an Apple
Power Mac G4/400 using the AltiVec stream instructions to prefetch data.
Compiler:
MetroWerks CodeWarrior Pro 5.3, MW C/C++ PPC 4.0
Compiler flags:
Unsigned chars, auto-inline
PowerPC struct alignment, Strings Read-Only, Static data in TOC,
use FMADD & FMSUB, No Traceback Tables,
schedule for AltiVec, optimize for speed, peephole optimizer on,
global optimization level 4
Dead strip static initialization code
stack size 64k, heap size 11000k
If you're interested in the source mods, let me know. I may play with them
some more yet as I learn how to use Apple's instrumentation tools. I'm
curious as to why the Add test didn't benefit nearly as much from the
streaming instructions as the others did.
Thanks!
-- Anton
-------------------------------------------------------------
This system uses 8 bytes per DOUBLE PRECISION word.
-------------------------------------------------------------
Array size = 400000, Offset = 0
Total memory required = 9.2 MB.
Each test is run 10 times, but only
the *best* time for each is used.
-------------------------------------------------------------
Your clock granularity/precision appears to be 10 microseconds.
Each test below will take on the order of 21671 microseconds.
(= 2167 clock ticks)
Increase the size of the arrays if this shows that
you are not getting at least 20 clock ticks per test.
-------------------------------------------------------------
WARNING -- The above is only a rough guideline.
For best results, please be sure you know the
precision of your system timer.
-------------------------------------------------------------
Function Rate (MB/s) RMS time Min time Max time
Copy: 477.0779 0.0136 0.0134 0.0138
Scale: 465.2854 0.0139 0.0138 0.0143
Add: 445.5377 0.0217 0.0215 0.0219
Triad: 442.0500 0.0220 0.0217 0.0226
-- This is an unauthorized communication. "The statements and opinions expressed herein are my own and do not necessarily represent those of Adaptec."
This archive was generated by hypermail 2b29 : Tue Apr 25 2000 - 01:49:24 CDT