Author: Robert Hyatt
Date: 13:24:20 09/30/02
Go up one level in this thread
On September 30, 2002 at 16:07:37, Jeremiah Penery wrote: >On September 30, 2002 at 12:26:36, Eugene Nalimov wrote: > >>Wrong. Some P4 optimizations hurt AMD. > >Then I suppose they hurt P2/P3 just as much. Either way, my point is still >valid, except for the psychotic cases where some optimization helps one and >hurts the other (I'm sure there aren't a whole lot). This is a _HUGE_ can of worms. IE if you look carefully at the various Intel books, what is good on one processor is not so good on another. The 16 bit code on the original pentium is a good case-in-point, as it buries the P6 processor badly. I've found this kind of stuff on every machine I have ever gone into deeply trying to optimize assembler code. Including the Crays, which "changed the rules" from time to time. When you try to go _really_ fast, you have to really study the machine, often using short code snippets in a big loop to see which is really faster or slower. And that test is only good on that particular processor version, in general. It _might_ be good on others, but there is no guarantee at all. > >>Thanks, >>Eugene >> >>On September 30, 2002 at 00:09:28, Jeremiah Penery wrote: >> >>>On September 29, 2002 at 23:31:36, Robert Hyatt wrote: >>> >>>>I don't know what this means. I have several dozen programs (Crafty >>>>is only one) that we have run using intel's compiler and gcc, and in >>>>_every_ case, Intel's compiler is faster. On P2's, on P3's and on >>>>P4's... Of course I wouldn't use intel's compiler for an AMD chip, >>>>why would they want to optimize for a competitor's chip??? >>> >>>They don't have to optimize specifically for the competitor's chip, as Intel >>>compiler still produces probably the fastest binaries for AMD machines. Any >>>general optimizations (P2, P3, and even P4 optimizations (excluding SSE2 stuff >>>or whatever)) are just as helpful for AMD processors as they are for Intel ones.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.