P-1 before LL
 

Not sure if this question belongs here or in the Software subforum:

Is there a way to set a worker to do P-1 prior to LL on the same exponent, or are we limited to setting each worker to do one [B]or[/B] the other?

Sorry if this question has been answered already, but nothing jumped out at me during a visual scan, and the terms are common enough that Search might yield thousands of results to wade through. At least, I didn't come up with rare enough search terms.

Thanks!

Rodrigo

You might be able to change the worktodo file (if you got the P-1 task) and force manual communication (avoiding duplication of work).

[QUOTE=Rodrigo;346503]Not sure if this question belongs here or in the Software subforum:

Is there a way to set a worker to do P-1 prior to LL on the same exponent, or are we limited to setting each worker to do one [B]or[/B] the other?

Sorry if this question has been answered already, but nothing jumped out at me during a visual scan, and the terms are common enough that Search might yield thousands of results to wade through. At least, I didn't come up with rare enough search terms.

Thanks!

Rodrigo[/QUOTE]

IIRC, this is the standard configuration: every exponent chosen for LL test should stand factorization up a defined limit, and P-1 before starting LL, unless:

a - Someone already did the factorization work stand-alone, or
b - The PC has not a comfortable RAM disposition to do P-1.

Luigi

If you didn't

Do you want to [U]duplicate[/U] P-1 work, or just to be sure that you [U]don't miss[/U] the P-1 work which has to be done before any LL, in case it was NOT done? Because those are two different things. (well the question is a bit odd, as you anyhow duplicate a lot of work, because the checkpoint files are not stored in case of P-1, and you start every time from scratch).

It should be nice if, depending on your memory settings for P95, the program would calculate a B1 and B2 limits and would do some more P-1 when those limits are over the "already done" values. But the real life in different. What you can do is to set a lot of memory for P-1 stage 2, and modify the "worktodo.txt" to replace the last ",1" to ",0" in all [URL="http://www.mersennewiki.org/index.php/Worktodo.txt"]"Test=" and "DoubleCheck=" lines[/URL]. That would convince P95 to always do "heavy" P-1 to all expos, regardless of the fact that the work was done before or not (pr poorly, partially, etc). Also, to get rid of the burden, you may take exponents from GPU72, which are well TF-ed and P-1-ed.

Also, see the "SequentialWorkToDo=0" in undoc.txt file, that may be what you want.

[QUOTE=ET_;346511]IIRC, this is the standard configuration: every exponent chosen for LL test should stand factorization up a defined limit, and P-1 before starting LL, unless:

a - Someone already did the factorization work stand-alone, or
b - The PC has not a comfortable RAM disposition to do P-1.

Luigi

If you didn't[/QUOTE]
Luigi,

Something seems to be missing at the end there. :smile:

Rodrigo

[QUOTE=LaurV;346512]Do you want to [U]duplicate[/U] P-1 work, or just to be sure that you [U]don't miss[/U] the P-1 work which has to be done before any LL, in case it was NOT done? Because those are two different things. (well the question is a bit odd, as you anyhow duplicate a lot of work, because the checkpoint files are not stored in case of P-1, and you start every time from scratch).

It should be nice if, depending on your memory settings for P95, the program would calculate a B1 and B2 limits and would do some more P-1 when those limits are over the "already done" values. But the real life in different. What you can do is to set a lot of memory for P-1 stage 2, and modify the "worktodo.txt" to replace the last ",1" to ",0" in all [URL="http://www.mersennewiki.org/index.php/Worktodo.txt"]"Test=" and "DoubleCheck=" lines[/URL]. That would convince P95 to always do "heavy" P-1 to all expos, regardless of the fact that the work was done before or not (pr poorly, partially, etc). Also, to get rid of the burden, you may take exponents from GPU72, which are well TF-ed and P-1-ed.

Also, see the "SequentialWorkToDo=0" in undoc.txt file, that may be what you want.[/QUOTE]

From the two choices in your first paragraph, I'd prefer to do the latter.

I guess that my question has to do with the fact that, [B]sometimes,[/B] one of my workers will perform P-1 before starting an LL. Therefore I was wondering if there is a way to set things so that the worker [B]always[/B] picks out exponents that need P-1 work, and then (if applicable) goes on to do the LL on that exponent.

A (maybe) separate item: the long paragraph in your reply (the part dealing with setting the last value to 0) appears to involve duplicating a lot of work previously done, would that be right?

Will experiment with the "SequentialWorkToDo=0" setting and see how it works out.

Thanks!

Rodrigo

[QUOTE=Rodrigo;346538]Luigi,

Something seems to be missing at the end there. :smile:

Rodrigo[/QUOTE]

It was not missing, it was exceeding... :smile:

[QUOTE=Rodrigo;346540]From the two choices in your first paragraph, I'd prefer to do the latter.
[/QUOTE]
Indeed that was my guess, still my question was not very clear, it did not clarify (for the second case) if you want [U]to do[/U] or [U]to avoid[/U] doing P-1. But your next paragraph clarified it perfectly.
[QUOTE]
I guess that my question has to do with the fact that, [B]sometimes,[/B] one of my workers will perform P-1 before starting an LL. Therefore I was wondering if there is a way to set things so that the worker [B]always[/B] picks out exponents that need P-1 work, and then (if applicable) goes on to do the LL on that exponent.
[/QUOTE]
That was intended, and it was "normal" behavior long ago before we became faster in doing P-1 stuff with the GPUs. If you only want to get exponents which have no P-1 done enough, then you better pick them from the "seventies" or "eighties" (70-80M range) where the P-1 front did not reach yet. Caution: this is only suitable if you have an old computer with a lot of RAM. New computers are better doing LL tests. Otherwise you better let the GPUs do P-1, which is faster, or some guys with old computers which would need to wait too much for finishing LL tests and prefer to do P-1 (otherwise, you take the bread from their mouth, well, not really, there is enough work for everybody, but figuratively speaking).
[QUOTE]
A (maybe) separate item: the long paragraph in your reply (the part dealing with setting the last value to 0) appears to involve duplicating a lot of work previously done, would that be right?[/QUOTE]
Yes indeed, this was intended for the case when you WANT to do P-1, regardless of the status (case 1 in the first paragraph). This makes sense (as I said) in case youhave [U][B]a lot[/B][/U] of RAM memory allocated for stage 2, [B][U]and[/U][/B] you want to extend the B1/B2 limits for P-1. A lot of people do this, hoping to find record factors, and indeed, they duplicate lots of effort, as they re-calculate the b^E for stage 1 every time.

The design was done like that from the inception, is not "good" nor "bad", just the PrimeNet server does not store the checkpoint files for P-1. Those are huge files and storing them would need lots of space, and will generate lots of traffic, and may not be "safe" anyhow (some mechanism is needed to forbid bad guys uploading wrong residue files). So, every worker who wants to extend B1/B2 limits will [U][B]duplicate[/B][/U] the work done by the former workers (and do some additional). With the new GPU toy it would be possible to store the "end of stage 1" files and when a larger B1 is supplied, the program will only "extend" the calculus and store the new file too. Some guys (me included!) will have "databases" of those "EOS1" files, for people interested in extending P-1 bounds. A method how to share those and how to check they are "real" may be discussed in the future.

I just realized I never got back to LaurV for his thorough explanation. Thank you very much!

At this stage (so to speak) it sounds like it'll be simpler just to assign specific workers to focus on P-1 and let others do LL separately.

I'll tune in to this channel periodically to stay up to date on developments.

Rodrigo

[QUOTE=LaurV;346607]That was intended, and it was "normal" behavior long ago before we became faster in doing P-1 stuff with the GPUs. If you only want to get exponents which have no P-1 done enough, then you better pick them from the "seventies" or "eighties" (70-80M range) where the P-1 front did not reach yet. Caution: this is only suitable if you have an old computer with a lot of RAM. New computers are better doing LL tests. Otherwise you better let the GPUs do P-1, which is faster, or some guys with old computers which would need to wait too much for finishing LL tests and prefer to do P-1 (otherwise, you take the bread from their mouth, well, not really, there is enough work for everybody, but figuratively speaking).[/QUOTE]

So I have an Athlon II X4 640 (4 cores @ 3.0 Ghz, 512KB L2) with 16 GB of RAM... is P-1 the best use of this machine? Or is LL still a better use of it?

[QUOTE=Mark Rose;357433]So I have an Athlon II X4 640 (4 cores @ 3.0 Ghz, 512KB L2) with 16 GB of RAM... is P-1 the best use of this machine? Or is LL still a better use of it?[/QUOTE] If you ran 4 threads of P-1 with upto 2.5 GB each, that would help. There is a need for CPU's doing P-1.