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-   -   Dual CPU perfomance hit (https://www.mersenneforum.org/showthread.php?t=7)

binarydigits 2002-10-11 16:56

[quote="xtreme2k"]It isnt incorrect.

Factoring is only WORTH 10% of the time used in P90 years. That is, if factoring a number took your computer 1 P90 year, only 0.1 P90 year will be credited. Thats where the 10% comes from.[/quote]

For over three years I have been getting about 0.7 P90 year credit for every 1 P90 year spent factoring (if no factor is found). That's where my 70% figure comes from; you still haven't shown me where the 10% comes from. If you are getting that from the quoted section where it says "encourages a pattern of applied CPU time... about a 10:1 ratio of LL CPU time to factoring CPU time" then you misunderstand what that says. George was just hoping we would spend 10 times as much time on LL as on TF.

xtreme2k 2002-10-11 17:33

I would like George to actually clarify the weighting in terms of CPU years. My understand and RESULTs is that factoring is only worth 10% of the time taken. There is no point arguing as I cannot be 100% I am currect but from experience that seems true for me.

ET_ 2002-10-11 17:40

[quote="xtreme2k"]factoring is only worth 10% of the time taken.[/quote]

But in the time needed to complete a LL-test you can do many TF...
If you complete 7 TF in the time you would complete one LL, you should have a 70% efficiency.

Or maybe I am wrong...

Luigi :shock:

xtreme2k 2002-10-11 17:48

I will state my understanding again. It might not be true but this is what I understand. And I seriously hope George can enlight me with some real info.

If your computer, say it is a Pentium 90, took 1 complete year to run a LL test, submit the results and you will get 1 year credited to your account.

If the same computer, ran 20 factors and took 1 year in total. Your account will be credited 10% of that, that is 0.1 year is credited in your accounts total.

THis is MY understanding and may or may not be correct. That is why I want someone who actually knows and tell me whats going on.

Until this is cleared up, I personally DO NOT recommend anyone to run Factoring if all they want is to get points to climb up the ladder.

BigRed 2002-10-11 19:20

Test mix for Pual P3s
 
[quote="lycorn"][b]BigRed[/b]
I think that definitely the best move is to choose but First-time primality tests, and keep away from the 33M exponents. This way every new test stands some chances of finding a prime, and you´ll be moving faster up the charts, which is more motivating. You have fast enough machines for LL testing, leave the TF work for slower ones.[/quote]

I'll be moving the Dual P4s with PC-800 to pairs of 1st time tests. That is what I get with WorkPreference=0, right?
The dual P3s with PC-133 will do one factoring and one 1st time test. The slow RAM should contrain things were I to do a pair of LLs.
The single P4s will do 1st time tests.
The slower boxes (down to Pentium II (Deschutes)) will do double checking.
Sound reasonably optimal?

garo 2002-10-11 21:12

xtreme2k,
You understanding is incorrect. Anyway, Factoring CPU time is on a different list than LL test CPU time so climbing up those two lists are totally different matters.

You are misinterpreting George's recommended mix. Obviously, no amount of explenation from me will convince you so we will wait for George. But chew on this fact. Back in March when TPR did it's first gauntlet we worked mostly on factoring. At that time, we were able to get approx 10 Factoring CPU years per day. Now if your 10% estimate was correct, when we switched back to LL tests we should have been at 100 CPU year per day. But we were infact nowhere near that number. The stats are available on the TPR website for you to see.

But it might just be easier if George comes by.....

garo 2002-10-11 21:16

Yes BigRed,
That is ideal. It is optimal from the project's point of view and also from the pov of optimizing your machines.

outlnder 2002-10-12 00:00

[b]BigRed[/b]

If you are so inclined, would you post your result times of the dual P4s running 2 LL tests. Let's see if RDRAM does minimize the bandwidth bottleneck.

xtreme2k 2002-10-12 10:29

As I said I would love George to clarify it for us. :)

Anyway post some benchmarks about running LL/F mix and LL/LL and F/F on dual systems. I think Double checking is exactly the same as LL therefore Dual P2 might benefit from F/F or LL/F on both cpu.

BigRed 2002-10-12 20:41

Posting result times
 
[quote="outlnder"][b]BigRed[/b]

If you are so inclined, would you post your result times of the dual P4s running 2 LL tests. Let's see if RDRAM does minimize the bandwidth bottleneck.[/quote]

So, what's needed for the result times? Just the couple of timestamped lines from results.txt showing the end of the previous factoring and then the completion of the next factor? Do we care about P-1 times too?

outlnder 2002-10-12 22:49

I would like to see the times for the completed work, i.e. -times for 2 concurrent LL tests and then times for multiple TF tests during a LL test.

ex- 2 LL= 11 days 13 hrs 56 min. for 15M and 12 days 2 hrs 05 min for 15.2M

ex- 1 LL 14 TF = 10 days 12 hrs 16 min for 15M and 14 TF in 10 days 18 hrs 11 min.


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