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Old 2022-07-13, 10:00   #20
lycorn's Avatar
Sep 2002
Oeiras, Portugal

2·33·29 Posts

Originally Posted by Prime95 View Post
Interestingly, in my limited testing it seems that, unlike P-1, B2 > ~1000 * B1 does not make sense. You are better off running more curves or increasing B1. In some situations, prime95 elects not to use all the available memory -- this will mean the default MaxHighMemWorkers setting might need to change.
I started doing some ECM work using 30.9. If I understood correctly, only stage 2 has benefited from the improvements implemented. So I didn´t quite understand why you wrote there´s no point in using B2 > ~1000B1.
I am running some tests on very little exponents, as I remember from some work done years ago they were the ones most favoured by GMP-ECM. For M4567, the ECM Progress page indicates ~20k curves already run for B1 = 110,000,000; I started with B1=150,000,000 and B2 ~1000B1, but the running time of Stage 2 was ridiculously small compared to stage 1´s.
After some adjustments I settled with B1 = 110,000,000 and B2 = 6e13. On a 4-core i5-7400 @ 3.3 GHz, with 27.5 GB available to Prime95, I am getting 16 minutes and 12 minutes for Stage 1 and Stage 2 respectively. This seems to be in line with some recommendations about the ideal ratio for running times I recall from previous work (Stage 2 taking ~70% of Stage 1 running time).
So far the software has been pretty stable, multithreading appears to be working fine. As for Prime95 using or not the available memory, I found that depends solely on the B2 used. With B2 = 1.5e12, stage 2 used ~50% of the allowed memory, with B2 = 3e13 ~70%, and with the current B2 = 6e13 it is using 26.3 GB.
Any idea/recommendation/suggestion for exponent size and/or bounds?
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