20031008, 14:40  #1  
Aug 2002
1015_{8} Posts 
Optimizing Athlon/Pentium3 Code
Prime95 said:
Quote:


20031008, 22:38  #2 
P90 years forever!
Aug 2002
Yeehaw, FL
2^{4}·17·29 Posts 
I started and stopped the effort. My P3 testbed (actually Celeron) died and I've also been kind of busy.
If you look around you'll see where I asked for some P3 benchmarks on two FFT sizes. The results were mixed  less than I had hoped for. The Athlon improvement was more than 10% if I recall correctly. I've not started the Proth speedup, but the two FFT sizes I did change were coded in such a way that the Proth speedup can be implemented too. What would be required to complete the effort? All x87 FFT sizes would need to be recoded too. The auxillary add and subtract routines need to be rewritten and tested. The Proth mod routine needs to be rewritten, etc. Even the P4 proth mod routine needs rewriting. The downside is the new version seems to be slower for P2 and older CPUs. Maintaining both code paths is not reasonable, so these slower CPUs would be stuck with version 23 or suffer with a slower newer version. 
20031009, 02:28  #3 
Aug 2002
2·3·53 Posts 
What about an AMD client and an Intel client??

20031010, 01:45  #4  
Aug 2002
Dawn of the Dead
5×47 Posts 
Aren't PII's by default put on trial factoring anyways, i.e., doublecheck cutoff at 500 MHz minimum? Besides, the enthusiaist who would still run archaic hardware would likely know which client to use anyways ... I doubt these machines contribute much to LL testing in the first place ... I don't want to think of my 350 crunching a 20000000M exponent ...
Athlons however do have a significant impact on production ... despite our mass adoption of Northwood technology, TPR still has hundreds of AMD machines ... they need the optimization ... Quote:
Last fiddled with by PageFault on 20031010 at 01:48 

20031012, 14:50  #5  
Aug 2002
3·5^{2}·7 Posts 
Quote:


20031014, 04:13  #6  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}·3·641 Posts 
Quote:
P1 factoring is included in PrimeNet factoring assignments, and it uses FFT multiplication. So the effect of an FFT change on preP3 models does need to be considered. Last fiddled with by cheesehead on 20031014 at 04:17 

20031015, 04:23  #7  
"Richard B. Woods"
Aug 2002
Wisconsin USA
2^{2}×3×641 Posts 
Quote:
Sorry, PageFault ... I misremembered, and I should've checked before posting. 

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