Benchmarks: AMD64 vs i386 on Dual 246 Opteron

[ray at redshift.com]

At 05:05 PM 7/28/2005 +0800, Erich Dollansky wrote:
| Hi,
| 
| ray at redshift.com wrote:
| 
| > MySQL, re-ran the benchmarks.  Much to my surprise, just changing the OS
from 64
| > bit to 32 bit caused the machine to double in speed.  The results are attached
| 
| I do not wonder at all.
| 
| I did some software development for PA-RISC and SPARC machines. Naiv as 
| I am, I started with the perfect 64 bit program which resulted in bad 
| performance.
| 
| I then collected hints of how to mix 8, 16, 32 and 64 bit data to make 
| the program much faster. The TCP/IP based application run then five 
| times faster on the same machine compared to the plain 64 bit program.
| 
| 64 bit programs copy to many unused information around.
| 
| It will be very difficult to tune a huge source base to maximum 
| performance and keep it compatible between 32 and 64 bit.
| 
| The pointers mentioned by you are only a small part of the problem. The 
| main problem is - at least in my program, and as far as what I saw in 
| the sources here - the data handling.
| 
| Erich

Thank you for the info - that makes sense and certainly backs up what I was
seeing as well.

Ray