Re: Mersenne: P-1 on PIII or P4?
At 01:16 AM 3/11/2003 +, Daran wrote: I don't think George's '1 or 2 extra temporaries' theory stands up. Sure it does. I fired up the debugger and the P4 has 5541 temporaries and the x86 has 89 temporaries. Hmmm, maybe I'd better look into it a little bit further --- Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.459 / Virus Database: 258 - Release Date: 2/25/2003
Re: Mersenne: P-1 on PIII or P4?
On Mon, Mar 10, 2003 at 09:05:41PM +, Brian J. Beesley wrote: > On Monday 10 March 2003 07:49, Daran wrote: > I just tried Test=8907359,64,0 on two systems - an Athlon XP 1700+ and a > P4-2533, both running mprime v23.2 with 384 MB memory configured (out of 512 > MB total in the system). These were fresh installations, I did nothing apart > from adding SelfTest448Passed=1 to local.ini to save running the selftest. > > The Athlon system picked B1=105000, B2=1995000 whilst the P4 picked > B1=105000, B2=2126250. So it seems that P4 is picking a significantly but not > grossly higher B2 value. My Duron 800 picks values identical to your Athlon with 384MB allowed. No change at 400MB At 420MB B2 goes up to 2021250, still lower than your B2 value. At 504MB B2 remains at 2021250. I don't think George's '1 or 2 extra temporaries' theory stands up. > Regards > Brian Beesley Daran G. _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: P-1 on PIII or P4?
Daran wrote: > > I'd appreciate it if you > or someone else could try starting a P-1 on the same exponent (not in one of > the ranges where it would get a different FFT length) on two different > machines, with the same memory allowed. P4: M8769809 completed P-1, B1=45000, B2=72, E=12, WY2: E2F4FF67 Memory allowed: 896MB (Machine has 1GB) PIII: M8769809 completed P-1, B1=45000, B2=72, E=12, WY2: E2F4FF67 Memory allowed: 990MB (Machine has 1 1/8GB) -- [EMAIL PROTECTED] - HMC UNIX Systems Manager _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: P-1 on PIII or P4?
At 13:05:41, Monday, 3/10/03, Brian J. Beesley wrote: > I just tried Test=8907359,64,0 on two systems - an Athlon XP 1700+ and a > P4-2533, both running mprime v23.2 with 384 MB memory configured (out of 512 > MB total in the system). These were fresh installations, I did nothing apart > from adding SelfTest448Passed=1 to local.ini to save running the selftest. > The Athlon system picked B1=105000, B2=1995000 whilst the P4 picked > B1=105000, B2=2126250. So it seems that P4 is picking a significantly but not > grossly higher B2 value. > Yes, I checked, both systems are using 448K run length for this exponent > (though it's only just under the P4 crossover). Maybe the P-1 bounds calculation accounts for the slightly slower than normal iteration time that 8907359 would have on a P4 because of the roundoff checking (since it is very close to the P4 512K FFT limit). -- Nick Glover [EMAIL PROTECTED] "It's good to be open-minded, but not so open that your brains fall out." - Jacob Needleman _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: E=12 on P4
On Sun, Mar 09, 2003 at 08:18:18PM -0800, Chris Marble wrote: > Chris Marble wrote: > > > I set up a P4 with 1GB RAM to grab some DCs. All need P-1 run. I cranked up > the memory available in local.ini and it's running with E=12. The 1st exponent > completed. It finished P-1 on the second in just over 3 hours - also with E=12. > I killed the mprime, moved the exponent to the end of Worktodo.ini and started > mprime back up. I'll check back in a couple of hours and see if I should > rotate to the next exponent. Then I will have a hunk of nicely P-1 DCs I can > move off to boxes with out enough RAM for the deep searches. > Sound right? What Anurag said. Will save yourself a lot of bother. Also *definitely* set SkipTrialFactoring=1 in local.ini. It's unlikely you'll get any DCs needing more TF, but if you do, you want to leave that to a non-P4. Just over three hours is slower than I would have expected. My humble, non-SSE2 capable 800MHz Duron has been taking about 3 3/4 hours to complete a DC P-1 with the standard client. Possible reasons are:- 1. Your FFT length is probably greater. All my recent work has been done on exponents < 9071000, but current DC assignments are ~ 9175000 2. You're using an E=12 plan, in comparison with my E=4. (I haven't been recording the timings of my modified client, which uses E=12.) Higher E is quite a bit more expensive in processing time, but should find more factors. To get an E=12 plan, your D value (which isn't recorded in results.txt) must be > 420. (My D=420) I would guess your D=630 or perhaps even 840. Higher D finds roughly the same number of factors more cheaply than lower D, but I doubt this is enough to offset the increased cost of E=12 How much memory is actually being used in stage 2? 3. Typical values of my B1 and B2 have been 5 and 75 respectively. Are yours higher? I would be *very* interested if you could send me any stage 2 factors you find. Just copy the two line report in results.txt, and confirm the E value (which is only recorded when a P-1 fails, but won't change unless either the memory settings or the FFT size changes.) > [EMAIL PROTECTED] - HMC UNIX Systems Manager Daran G. _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
Re: Mersenne: P-1 on PIII or P4?
At 09:05 PM 3/10/2003 +, Brian J. Beesley wrote: On Monday 10 March 2003 07:49, Daran wrote: > Or is there some > reason I can't think of, why higher values might be appropriate for a P4? George? The Athlon system picked B1=105000, B2=1995000 whilst the P4 picked B1=105000, B2=2126250. So it seems that P4 is picking a significantly but not grossly higher B2 value. I looked at the bounds picking code and there is no special action taken for the P4. The only place I can see a difference is in the calculation of number of temporary variables. The P4 FFT uses a denser memory layout than the x86 FFT. Thus you might get an extra temporary or two. And you just happened to hit a boundary condition where the extra temporary allowed P-1 to use a more efficient stage 2 implementation and consequently it pays to run stage 2 a little longer. Only running prime95 with the debugger on could prove this theory. --- Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.459 / Virus Database: 258 - Release Date: 2/25/2003
Re: Mersenne: P-1 on PIII or P4?
On Monday 10 March 2003 07:49, Daran wrote: > > B1 and B2 are supposed to be chosen by the client so that the cost/benefit > ratio is optimal. Does this mean that P4s is choose B2 values which are > too high? Or does everything else choose values too low? Or is there some > reason I can't think of, why higher values might be appropriate for a P4? George? > > In fact, I'm not even sure it does get a higher B2 - the apparent > difference could be, as Brian suggested, due to differences between > versions. I don't have access to a P4, so I can do any testing, But I'd > appreciate it if you or someone else could try starting a P-1 on the same > exponent (not in one of the ranges where it would get a different FFT > length) on two different machines, with the same memory allowed. You would > not need to complete the runs. You could abort the tests as soon as > they've reported their chosen limits. I just tried Test=8907359,64,0 on two systems - an Athlon XP 1700+ and a P4-2533, both running mprime v23.2 with 384 MB memory configured (out of 512 MB total in the system). These were fresh installations, I did nothing apart from adding SelfTest448Passed=1 to local.ini to save running the selftest. The Athlon system picked B1=105000, B2=1995000 whilst the P4 picked B1=105000, B2=2126250. So it seems that P4 is picking a significantly but not grossly higher B2 value. Yes, I checked, both systems are using 448K run length for this exponent (though it's only just under the P4 crossover). Regards Brian Beesley > > > Would I unreserve all the exponents that are already P-1 complete? > > If I don't change the DoubleCheck into Pfactor then couldn't I just let > > the exponent run and then sometime after P-1 is done move the entry and > > the 2 tmp files over to another machine to finish it off? > > If you're going to feed your other machines from this one, then obviously > you won't need to unreserve the exponents they need. But there's an easier > way to do this. Put SequentialWorkToDo=0 in prime.ini, then, so long as it > never runs out of P-1 work to do, it will never start a first-time or > doublecheck LL, and there will be no temporary files to move. I also > suggest putting SkipTrialFactoring=1 in prime.ini. > > > That sounds like more work than I care to do... > > I agree that with 20 boxes, the work would be onerous. > > > ...I can see having 1 machine > > do P-1 on lots of double-checks. > > That would be well worth it. Since one box will *easily* feed the other > twenty or so, you will have to decide whether to unreserve the exponents > you P-1 beyond your needs, or occasionally let that box test (or start > testing) one. > > You may find a better match between your rate of production of P-1 complete > exponents, and your rate of consumption, if you do first-time testing. > > [...] > > > As an mprime user I edit the local.ini file all the time. Per your notes > > I upped *Memory to 466. > > That will certainly help exponents below 9071000 on a P3, or 8908000 on a > P4. The current DC level is now over 917, so I doubt this will help > much, (though of course, it won't harm, either). I haven't tried. I'm > still getting enough sub 9071000 expiries. > > > -- > > [EMAIL PROTECTED] - HMC UNIX Systems Manager > > Daran G. > _ > Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm > Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers _ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
