Sieve Benchmark Thread - Page 6

Flatlander · 2010-06-16, 22:44

Quote:

Originally Posted by axn

Can NewPGen cover the same range (ie 1.2-1.8G) in 30 min?

iirc I think it takes an hour or more.

Quote:

Originally Posted by axn

...
Can you post some timing for NewPGen to take a 1T (or 2T or whatever) range from p=1.8G to p=3G in increments of 0.2G? That'll give me a clue as to what is a good cutoff point.

I'll try.

Quote:

Originally Posted by axn

...
PS:- There is another idea that'll give me a 5x speed improvement. But this involves sieving candidates out of order (technically, residue classes mod 7*11*13). So the candidates will have to be sorted after the sieving step.

Sounds good. I wouldn't know how to sort them tho'.

Quote:

Originally Posted by axn

192 Mb is what newpgen automatically chooses. But it can work with much less while still using fast array mode (96 Mb, maybe even 48 Mb). I am going to go out on a limb and say that 384 MB fast array can handle ranges much larger than 20T (yes, 20, not 2).

PS:- I remember there being a rule saying something like 6 bytes per k. That'd mean 384 MB can handle 64M (=67108864) candidates in fast array mode.

So are you saying that sieving maybe 20T and feeding it into NPG is about optimal with the software as it is now? :surprised

axn · 2010-06-16, 23:04

Quote:

Originally Posted by Flatlander

So are you saying that sieving maybe 20T and feeding it into NPG is about optimal with the software as it is now? :surprised

Well maybe 10T (in light of amphoria's post).

Quote:

Originally Posted by amphoria

Unfortunately that is not what I experienced. With 32.5M candidates it used normal array mode.

Flatlander · 2010-06-16, 23:19

Quote:

Originally Posted by Flatlander

...
Testing underway for 90e6/90e5, P=1,824,261,409. Looks like 2T will take about 6hr 15m. (Uses 1,833,380KB.)

Took 6hrs 17mins with the computer in use for browsing etc.
0.01T sample identical to NPG output (except header again.)

I'll try to get some timings in NPG tomorrow.

Flatlander · 2010-06-17, 18:30

Some NPG timings. I wasn't able to take all of them at regular intervals but you should be able to get a curve from them.
Small variation (10s) due to saving the file every 20m but other variations I can't explain. The other core was idle.

2T range.
Start P=1,824,261,409
to 1.9G 13m 08s
to 2.0G 14m 04s
to 2.1G 13m 08s
to 2.3G 28m 20s
to 2.4G 13m 15s
to 2.5G 12m 38s
to 3.242G 1hr 19m
to 3.4G 15m 2s
to 3.506G 9m 26s
to 3.6G 8m 1s
(Sorry for the messy data. We had visitors!)

I ran a 5T range on axnSieve (same PC) last night (90e6/90e5) and it took 14hrs 54m. A negligible slow down compared to 60e6/60e5.
NPG is now running the file using fast array, 384Mb.

amphoria · 2010-06-17, 19:00

I have finished re-running 17T-18T using axnSieve and NPG and the results match NPG only exactly.

I have found that with 32-bit Windows I get a runtime error 215 if I set SmallPrimes to 18e6 or greater. With SmallPrimes set to 12e6 it is fine. This is an arithmetic overflow error. Is it possible that this is a limitation of 32-bit?

axn · 2010-06-17, 19:07

Quote:

Originally Posted by amphoria

I have found that with 32-bit Windows I get a runtime error 215 if I set SmallPrimes to 18e6 or greater. With SmallPrimes set to 12e6 it is fine. This is an arithmetic overflow error. Is it possible that this is a limitation of 32-bit?

Can you rebuild with -gl flag, no other optimizations turned on, and post the debug output?

amphoria · 2010-06-17, 19:45

Quote:

Originally Posted by axn

Can you rebuild with -gl flag, no other optimizations turned on, and post the debug output?

In order to compile with -gl I switched from using the IDE to using the command line compiler and the problem has gone away. It looks like the IDE was using a compiler option that was causing the problem. Note I only used the default options in the IDE.

Currently testing with SmallPrimes = 30e6.

axn · 2010-06-18, 03:05

Quote:

Originally Posted by Flatlander

2T range.
Start P=1,824,261,409
to 1.9G 13m 08s
to 2.0G 14m 04s
to 2.1G 13m 08s
to 2.3G 28m 20s
to 2.4G 13m 15s
to 2.5G 12m 38s
to 3.242G 1hr 19m
to 3.4G 15m 2s
to 3.506G 9m 26s
to 3.6G 8m 1s

Looks like there is some more performance gain to be had. I'll do some modifications this weekend.

amphoria · 2010-06-18, 15:54

Unfortunately I spoke too soon. With the command compiler the outer loop in do_sieve_iter is not terminating. If I terminate it with Ctrl-C I loose some of the candidates at the end of the file.

Is it posisble that the commmand line compiler uses an aggressive optimisation that messes up the compilation of the loop? Has anyone else managed to compile LuckyMinus under Windows?

I've currently reverted to the IDE compiled version with SmallPrimes = 15e6.

Flatlander · 2010-06-18, 17:08

Quote:

Originally Posted by amphoria

...Has anyone else managed to compile LuckyMinus under Windows?

64-bit Windows 7, yes. I haven't tried 32-bit XP yet. (Under Lazarus. See my 'Clueless' post above, number 48.)

Is the code optimized for/dependent on 64-bit for higher SmallPrimes?

axn · 2010-06-18, 18:01

Quote:

Originally Posted by Flatlander

Is the code optimized for/dependent on 64-bit for higher SmallPrimes?

No.

I've noticed that sometimes FPC code generation for "for loops" goes a bit wonky. Maybe a for-less code would be better.

2010-06-17, 18:30	#59
Flatlander I quite division it "Chris" Feb 2005 England 31×67 Posts	Some NPG timings. I wasn't able to take all of them at regular intervals but you should be able to get a curve from them. Small variation (10s) due to saving the file every 20m but other variations I can't explain. The other core was idle. 2T range. Start P=1,824,261,409 to 1.9G 13m 08s to 2.0G 14m 04s to 2.1G 13m 08s to 2.3G 28m 20s to 2.4G 13m 15s to 2.5G 12m 38s to 3.242G 1hr 19m to 3.4G 15m 2s to 3.506G 9m 26s to 3.6G 8m 1s (Sorry for the messy data. We had visitors!) I ran a 5T range on axnSieve (same PC) last night (90e6/90e5) and it took 14hrs 54m. A negligible slow down compared to 60e6/60e5. NPG is now running the file using fast array, 384Mb. Last fiddled with by Flatlander on 2010-06-17 at 18:30

2010-06-17, 19:00	#60
amphoria "Dave" Sep 2005 UK 2³·347 Posts	I have finished re-running 17T-18T using axnSieve and NPG and the results match NPG only exactly. I have found that with 32-bit Windows I get a runtime error 215 if I set SmallPrimes to 18e6 or greater. With SmallPrimes set to 12e6 it is fine. This is an arithmetic overflow error. Is it possible that this is a limitation of 32-bit? Last fiddled with by amphoria on 2010-06-17 at 19:00

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2010-06-18, 15:54	#64
amphoria "Dave" Sep 2005 UK 101011011000₂ Posts	Unfortunately I spoke too soon. With the command compiler the outer loop in do_sieve_iter is not terminating. If I terminate it with Ctrl-C I loose some of the candidates at the end of the file. Is it posisble that the commmand line compiler uses an aggressive optimisation that messes up the compilation of the loop? Has anyone else managed to compile LuckyMinus under Windows? I've currently reverted to the IDE compiled version with SmallPrimes = 15e6.