S9 and general sieving discussion

[Lennart]

Originally Posted by gd_barnes

Max has made me aware of the way PrimeGrid/PSP does sieving/testing on things at the same time, which we have not done in the past at NPLB/CRUS. From this point on, I will defer to our searchers with such experience when determining how far to sieve and when to start testing. For this, I'll defer to your knowledge on the topic. What would PrimeGrid do?

I feel that technically what we should do is use the type of machine that will be most used for sieving for a sieving rate and the type of machine that will be most used for testing in the future for a testing rate.

One question for you: As a simple example, let's say that we only loaded n=1.5M-1.6M into the server. Would you still continue to sieve n=1.5M to 2M further or would you only sieve n=1.6M-2M further?

If I run the tests on prpnet I should leave all candidates in the sievefile because it is very easy to remove factors by prpadmin.

It only takes some seconds so I use that.

Because of the slow computers I see now on s9 (not all) I started the sieving again and I think there is no harm in doing that.

I think this is a good way of sieving specially when it is a conjecture when you don't know where you going to find the primes that will eliminate a k.

When we come to time for tests it is very hard today If I do a test on a number with a modern i7 3.2Ghz no AVX can take 2 hr but on a i7 with AVX it will only take 1 hr.

On a c2q6600 it will take about 4 -5hr



Lennart

[TheCount]

I have one core of an AMD X6 1000T on the S9 port currently. Is taking about 7.5 hours to crunch one WU (6 completed in 44:36:55).

What machine to base the sieving level on? I would say the average machine over the life of the port should be the basis. Not my AMD CPU, (non AVX) etc. Maybe I will upgrade to Skylake next year with DDR4 and AVX-512?

[Lennart]

Originally Posted by TheCount

I have one core of an AMD X6 1000T on the S9 port currently. Is taking about 7.5 hours to crunch one WU (6 completed in 44:36:55).

What machine to base the sieving level on? I would say the average machine over the life of the port should be the basis. Not my AMD CPU, (non AVX) etc. Maybe I will upgrade to Skylake next year with DDR4 and AVX-512?

Most sieving is done on i7 2700 at 3.7Ghz.

It is on about 6 hr/f on that computer.
and I do them in about 4 hr when I llr them on that computer


Lennart

[Lennart]

45T-54T completed.


I will do some more because I see tests on the s9 port is not very fast.

Lennart

[mdettweiler]

Originally Posted by Lennart

45T-54T completed.


I will do some more because I see tests on the s9 port is not very fast.

Lennart

I should note: take the candidate ages you see reserved to my computers on the server with a grain of salt. Both of the computers I have running S9 right now only do PRPnet part-time (mostly at night) - they're laptops that go places during the day.

For a more accurate figure, I'm getting about 17,200 seconds = 4.7 hours/test on one of the laptops (Sandy Bridge i7 dualcore - i7-2620M).

[gd_barnes]

I just removed the factors up to P=54T in port 1300.

[Lennart]

Some more factors.

Lennart

[Lennart]

This is a strange sieve! I would like to get some sec. more but it moves very slow.

62T-70T done

I will now do it up to 80T and see if time increase anything.

Lennart

[gd_barnes]

Factors up to P=70T removed in port 1300.

[Lennart]

70T-80T complete and I stop here I am at ¨8 hr now.


Lennart