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Old 2022-01-15, 15:28   #45
nordi
 
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Quote:
Originally Posted by firejuggler View Post
A question I have : is it worthy to rerun a P-1 with the same bound if you find a factor in stage 1? (adding the factor found, obviously)
You mean in order to potentially find another factor in stage 2? Yes, it is.
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Old 2022-01-15, 17:57   #46
petrw1
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Default Some Bounds Testing

With 8-core i7-7820x PC
20.8M exponents at TF75
Assignments look like: Pminus1=N/A,1,2,20858423,-1,800000,0,75

Test: Alter RAM allocated
B2-Mult is from this line: With trial factoring done to 2^75, optimal B2 is 327*B1 = 261600000.
Interestingly the Mult% (Ratio) is close to the RAM Ratio
As RAM dropped, B2-Mult dropped and hence Pct. (Chance of a New Factor) dropped, but run time remained the same.

Code:
RAM	B2-Mult	Pct.	Mult%
24	327	5.35%	
16	227	5.08%	69.4%
12	173	4.87%	52.9%
8	124	4.63%	37.9%
Then I used this to calculate the 2 following tables.
Granted the numbers from this website do NOT exactly agree with the v30.8 numbers displayed but hopefully they are relative consistent enough to make the following reliable.

What new B1 do I need given the same B2-Mult to get the same Pct.?
(B1-M is Bound 1 in Millions)
Same Pct. but GDs drops.
Code:
RAM	B2-Mult	B1-M	B2-M	Pct.	GDs
24	327	0.8	261.60	5.41%	15.42
16	227	0.96	217.92	5.41%	13.13
12	173	1.1	190.30	5.40%	11.72
8	124	1.32	163.68	5.41%	10.45
What new B1 do I need given the same B2-Mult to get the same GhzDays?
(I'm guessing this will be closer to the same clock-time)
Same Gds but Pct. increases.
Code:
RAM	B2-Mult	B1-M	B2-M	Pct.	GDs
24	327	0.8	261.60	5.41%	15.42
16	227	1.13	256.51	5.66%	15.46
12	173	1.45	250.85	5.83%	15.45
8	124	1.95	241.80	6.01%	15.43

Last fiddled with by petrw1 on 2022-01-15 at 18:21 Reason: Removed My Vote just added
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Old 2022-01-16, 02:20   #47
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Quote:
Originally Posted by petrw1 View Post
What new B1 do I need given the same B2-Mult to get the same Pct.?
(B1-M is Bound 1 in Millions)
Same Pct. but GDs drops.
Code:
RAM	B2-Mult	B1-M	B2-M	Pct.	GDs
24	327	0.8	261.60	5.41%	15.42
16	227	0.96	217.92	5.41%	13.13
12	173	1.1	190.30	5.40%	11.72
8	124	1.32	163.68	5.41%	10.45
This B1-M is very nearly fitting with sqrt(ref RAM/allocated RAM) * B1@ref RAM !!! Also, eventhough it says it is lower GHzD, I suspect that the actual runtimes are pretty close or even increasing, since those GD numbers are from pre-30.8

Last fiddled with by axn on 2022-01-16 at 02:21
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Old 2022-01-16, 04:03   #48
petrw1
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Quote:
Originally Posted by axn View Post
This B1-M is very nearly fitting with sqrt(ref RAM/allocated RAM) * B1@ref RAM !!! Also, eventhough it says it is lower GHzD, I suspect that the actual runtimes are pretty close or even increasing, since those GD numbers are from pre-30.8
With the same PC I increased B1 from .8M to 1.1M and decreased RAM from 24GB to 12GB.
I had a similar success rate 5.35% vs 5.41%.
The run time was longer: Stage 1 took about 15% longer as expected.
Stage 2 did have a lower Bound2 181 vs 327 but with half as much RAM it took close to the same time as the prior run with 24GB of RAM.
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Old 2022-01-16, 05:49   #49
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Quote:
Originally Posted by Prime95 View Post
Please verify that 2.2 number, it was just a rough guess.
i7-7820x 24GB RAM
20.8M .8M/261.6M(B2=327xB1) - Stage1: 10 Min / Stage2: 9 Min = 19 Min Total - 5.35% / 17.6777 GhzDays
10.4M 1.76M/1169M(B2=664xB1) - Stage 1: 22 Min / Stage2: 13 Min = 35 Min Total - 6.74% / 36.5 GhzDays
I ran both tests with TF=75 bits rather than the actual TF level of 74 for the 10.4M. Should I have?
For exponent 50% smaller, 2.2x B1 seems to be too much; especially for Stage1 run times.

10.4M 75Bits 1.2M/786M (B2=655xB1) - Stage 1: 11 Min / Stage 2: 9 Min = 20 Min Total - 6.10% / 24.5581 GhzDays
10.4M 72Bits 1.2M/846M (B2=705xB1) - Stage 1: 11 Min / Stage 2: 9.5 Min = 20.5 Min Total - 7.89% / 26.3972 GhzDays
1.5X seems a good fit at least for this PC and for 20.8M vs 10.4M
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Old 2022-01-16, 09:44   #50
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.

Last fiddled with by S485122 on 2022-01-16 at 09:53 Reason: GHzdays are not relevant for 30.8 P-1 work but why bother
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Old 2022-01-16, 10:26   #51
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Quote:
Originally Posted by petrw1 View Post
i7-7820x 24GB RAM
20.8M .8M/261.6M(B2=327xB1) - Stage1: 10 Min / Stage2: 9 Min = 19 Min Total - 5.35% / 17.6777 GhzDays
10.4M 1.76M/1169M(B2=664xB1) - Stage 1: 22 Min / Stage2: 13 Min = 35 Min Total - 6.74% / 36.5 GhzDays
I ran both tests with TF=75 bits rather than the actual TF level of 74 for the 10.4M. Should I have?
For exponent 50% smaller, 2.2x B1 seems to be too much; especially for Stage1 run times.
This doesn't make sense. What were the stage 1 FFT sizes, per iteration timings and worker/thread configuration for these two runs?

While 2.2 might be a bit high, 2x or 1.9x _should have_ given comparable timings (twice as many iterations, half the per-iteration-time). Yet, you're off by 2.2x - it is as if the smaller FFT wasn't any faster at all. Does. Not. Make. Sense.

Last fiddled with by axn on 2022-01-16 at 10:27
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Old 2022-01-17, 04:13   #52
petrw1
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Quote:
Originally Posted by axn View Post
This doesn't make sense. What were the stage 1 FFT sizes, per iteration timings and worker/thread configuration for these two runs?

While 2.2 might be a bit high, 2x or 1.9x _should have_ given comparable timings (twice as many iterations, half the per-iteration-time). Yet, you're off by 2.2x - it is as if the smaller FFT wasn't any faster at all. Does. Not. Make. Sense.
I agree it seems odd; It could be a quirk in my PC.
Even with version 29 of Prime95 I got the best P-1 thruput with 8 Cores/ 1 Worker.

Exp / B1 : FFT1 / FFT2 : Stage1 / Stage2
20.8M / .8M : 1152K / 1280K : 9 Min / 9 Min
10.4M / 1.2M : 560K / 640K : 15 Min / 9 Min --- Not sure why Stage1 is slow here
5.2M / 1.8M : 280K / 320K : 8 Min / 7 Min --- But the times seem better here
Yes I'm thinking 1.5x is too low.

Anyone else want to run a few tests.
We are trying to determine how much to increase B1 when the exponent halves to get the same run time.
We think it is about 2x.

Last fiddled with by petrw1 on 2022-01-17 at 04:15
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Old 2022-01-17, 05:37   #53
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I can give you timing for my working range
3core/1 worker 10 Gb of mem

8.5M/1.56M: 448k/ 512k : 1550 sec/1000 sec

Last fiddled with by firejuggler on 2022-01-17 at 05:38
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Old 2022-01-17, 08:24   #54
Luminescence
 
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Quote:
Originally Posted by petrw1 View Post
I agree it seems odd; It could be a quirk in my PC.
Even with version 29 of Prime95 I got the best P-1 thruput with 8 Cores/ 1 Worker.

Exp / B1 : FFT1 / FFT2 : Stage1 / Stage2
20.8M / .8M : 1152K / 1280K : 9 Min / 9 Min
10.4M / 1.2M : 560K / 640K : 15 Min / 9 Min --- Not sure why Stage1 is slow here
I have noticed the same thing with smaller FFTs sometimes being slower. That’s not a quirk of your PC, but seemingly a quirk of AVX-512 FFTs.

I noticed that some FFTs are faster when using one worker on a 18 core CPU (Xeon W-2295), but slow down when using two or three workers. But FFTs that were slower to beginn with (one worker) do not slow down when using multiple workers.
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Old 2022-01-17, 16:33   #55
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Quote:
Originally Posted by firejuggler View Post
I can give you timing for my working range
3core/1 worker 10 Gb of mem

8.5M/1.56M: 448k/ 512k : 1550 sec/1000 sec
Thanks
Now could you try one or both of these to see if the run times are about the same.
- an exponent half the size with double the B1
- an exponent double the size with half the B1
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