Mersenne Digest Friday, June 22 2001 Volume 01 : Number 863 ---------------------------------------------------------------------- Date: Wed, 20 Jun 2001 08:06:28 +0200 From: "george de fockert" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Prime95 - V21.1.1 aka v21a - ----- Original Message ----- From: "Brian J. Beesley" <[EMAIL PROTECTED]> > It would also be interesting to find out if the PIII prefetch code > benefits the AMD K6 processor. The K6-2 and K6-3 do have an Athlon- > compatible prefetch instruction, though it's using 32-byte cache > lines and there is no prefetch queue i.e. only one prefetch can be > active at any time. Just tried it on my k6-2, needs CpuSupportsPrefetch=1 in local.ini, and results in an illegal instruction exception. So the program probably does not use the AMD 3dnow! prefetch instruction, PREFETCH(W), but one of the intel MMX2 or SIMD prefetch instructions not on the K6-2, PREFETCHNTA orPREFETCHT[123] > BTW what happens to the prefetch instructions for those processors > (like PII) that don't support prefetch? See above for the K6-2 George de Fockert _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 20 Jun 2001 08:51:11 -0700 From: Eric Hahn <[EMAIL PROTECTED]> Subject: Re: Mersenne: Prime95 - V21.1.1 aka v21a George Woltman wrote: >Some Athlons are seeing a speed increase others are not. The >two that I know are not enjoying a speed increase are running >under Win2K. Maybe there is a bug in the way v21.1 determines >if prefetch is supported. > >For those Athlon owners that are not seeing a speed boost, try setting > CpuSupportsPrefetch=1 >in local.ini This is a possibility. The other possibility is that there might be something in Windows that is interfering. The reason I say this, is that I have a P3 running at 733Mhz, and after a reboot, Prime95 was back to running at the same iteration time before v21 starting running. After stopping Prime95 and adding the line to local.ini, it was back to the increased speed. Interesting... to say the least... Eric P.S. BTW, this P3 is running Win98SE... _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 20 Jun 2001 16:55:04 -0400 From: George Woltman <[EMAIL PROTECTED]> Subject: Mersenne: More v21 Hi all, Regarding some of the comments on v21: The strange data output when doing an Advanced/Time on 10,000,000 is due to some instrumentation I accidentally left in. I have removed it and maybe it will speed up the program by a very, very, very tiny amount. You can download it at ftp://mersenne.org/gimps/p95v21a.zip I've built a Windows NT Service version and a Linux version. You can download them at ftp://mersenne.org/gimps/p95v21n.zip and ftp://mersenne.org/gimps/p95v21x.zip respectively. They have been through the "robust" QA process of proving M11213 prime. Use at your own risk! Brian Beesley, a big QA volunteer, will undoubtedly download the Linux version and report bugs or a higher level of confidence in mprime's capabilities. Since the prefetch code seems to work on the Athlon, I won't be needing the services of Athlon programmers or Orlando residents just now. Thanks to those that offered. Although, I'm sure we could get a few more percent by using PREFETCHW or by a modified memory layout for the 64-byte cache lines, I'll wait until v21 is finalized before looking at any more changes. Finally, the PPro, PII, and Celeron 1 do not crash when a prefetch instruction is encountered. This indicates to me that Intel planned on putting this instruction in prior to the PIII but ran into technical difficulties or time constraints. These CPUs are affected only by the prefetch instructions using up some cache space and decoder bandwidth. Thus, I'm reluctant to increase prime95's size by a third to support 4 different FFT algorithms: Pentium classic, Pentium Pro, Pentium Pro with prefetching, and SSE2. I haven't made a final decision yet (although I sure wish I'd put the FFT code in a DLL!) Regards, George _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 20 Jun 2001 15:32:24 -0700 (PDT) From: Francois Gouget <[EMAIL PROTECTED]> Subject: Re: Mersenne: Prime95 - V21.1.1 aka v21a On Tue, 19 Jun 2001, Brian J. Beesley wrote: [...] > Unfortunately I can't contribute timings to this argument as none of > my three Athlon systems can run Prime95 (they're all linux systems). Prime95 is available on Linux. It's called mprime and you can download it from: ftp://mersenne.org/gimps/mprime.tar.gz (glibc 2.1.3) ftp://mersenne.org/gimps/sprime.tar.gz (static) I even maintain a Debian package for it called prime-net. You will find it in the non-free/misc section. Of course, for version V21.1.1, I believe you're right. > Must dig out wine & see if Prime95 will run over wine/X/linux, though > that's a mightly roundabout way of running what's essentially a > console program!!! [...] I tried this but it does not work well. I could start prime95 once using 'wine --managed ./PRIME95.EXE' but couldn't start it again after that. - -- Francois Gouget [EMAIL PROTECTED] http://fgouget.free.fr/ The greatest programming project of all took six days; on the seventh day the programmer rested. We've been trying to debug the *&^%$#@ thing ever since. Resume: design before you implement. _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Wed, 20 Jun 2001 20:03:37 -0500 From: [EMAIL PROTECTED] (Mikus Grinbergs) Subject: Re: Mersenne: Prime95 - V21.1.1 aka v21a Tried the new V21 Linux version (p95v21x.zip). My original (35 um) Athlon got the same percentage speed increases that others have been reporting (did *not* have to explicity put in CpuSupportsPrefetch=1). One minor V21 difference: I was using the "Advanced/Time" option, and V20 would show each 'timing' line as it completed. But V21 did not change the screen appearance (after "Accept above answers?") until the whole multi-iteration 'timing' run was complete -- then it showed ALL the 'timing' lines at once, immediately followed by the elapsed time of the whole 'timig' run, plus the estimate of the time it would take to perform an LL test of the specified exponent. mikus _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 21 Jun 2001 11:10:28 -0500 From: "C. Daniel Sheets" <[EMAIL PROTECTED]> Subject: RE: Mersenne: More v21 I have noticed a bug in the new v21.1 program regarding Athlon computers. The CPU type gets changed from Athlon to Pentium II. This happens in both Prime95 v21.1 and NTPrime v21.1. Worse yet, it happens every time the program/service is started. I realize that this changes the projected end date but there may be other consequences that I am not aware of. Dan -----Original Message----- From: George Woltman [mailto:[EMAIL PROTECTED]] Sent: Wednesday, June 20, 2001 3:55 PM To: [EMAIL PROTECTED] Subject: Mersenne: More v21 Hi all, Regarding some of the comments on v21: The strange data output when doing an Advanced/Time on 10,000,000 is due to some instrumentation I accidentally left in. I have removed it and maybe it will speed up the program by a very, very, very tiny amount. You can download it at ftp://mersenne.org/gimps/p95v21a.zip I've built a Windows NT Service version and a Linux version. You can download them at ftp://mersenne.org/gimps/p95v21n.zip and ftp://mersenne.org/gimps/p95v21x.zip respectively. They have been through the "robust" QA process of proving M11213 prime. Use at your own risk! Brian Beesley, a big QA volunteer, will undoubtedly download the Linux version and report bugs or a higher level of confidence in mprime's capabilities. Since the prefetch code seems to work on the Athlon, I won't be needing the services of Athlon programmers or Orlando residents just now. Thanks to those that offered. Although, I'm sure we could get a few more percent by using PREFETCHW or by a modified memory layout for the 64-byte cache lines, I'll wait until v21 is finalized before looking at any more changes. Finally, the PPro, PII, and Celeron 1 do not crash when a prefetch instruction is encountered. This indicates to me that Intel planned on putting this instruction in prior to the PIII but ran into technical difficulties or time constraints. These CPUs are affected only by the prefetch instructions using up some cache space and decoder bandwidth. Thus, I'm reluctant to increase prime95's size by a third to support 4 different FFT algorithms: Pentium classic, Pentium Pro, Pentium Pro with prefetching, and SSE2. I haven't made a final decision yet (although I sure wish I'd put the FFT code in a DLL!) Regards, George _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 21 Jun 2001 19:28:23 -0000 From: "Brian J. Beesley" <[EMAIL PROTECTED]> Subject: Mersenne: FTP site - Service interruption Hi, I operate the ftp server lettuce.edsc.ulst.ac.uk which keeps copies of the Mersenne software and databases. It will be offline from approximately 12:00 GMT on Saturday 23rd June until 20:00 GMT on Sunday 24th June. The building in which it is housed requires urgent work to the main electrical power supply. I apologise for any inconvenience. Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 21 Jun 2001 17:49:27 EDT From: [EMAIL PROTECTED] Subject: Re: Mersenne: Good news for Pentium 3 and Celeron 2 owners George wrote: << For those Athlon owners that are not seeing a speed boost, try setting CpuSupportsPrefetch=1 >> I also needed to do this on my C700 under WinMe to get the expected speed boost. Timings dropped from 0.260 sec at 640K to 0.188 sec. Nice work! Alas, my dual-p3 office workstation runs under linux. Any chance of a prefetch-enabled version of mprime soon? cheers, - -Ernst _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 21 Jun 2001 23:58:10 -0400 From: George Woltman <[EMAIL PROTECTED]> Subject: Mersenne: v21 athlon becomes P2 bug Hi all, I think I've fixed the bug where Athlons are transformed into lowly Pentium II's when prime95 is started. This wasn't a serious bug - it really only affects the expected completion date and the cpu type reported by the primenet server. You can download the fix at ftp://mersenne.org/gimps/p95v21a.zip Regards, George _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ Date: Thu, 21 Jun 2001 18:08:08 +0100 From: "Lawrence Cairns-Smith" <[EMAIL PROTECTED]> Subject: Re: Mersenne: Good news for Pentium 3 and Celeron 2 owners Can I put a suggestion to the group...... I feel it is ridiculous that George has to beg/borrow the latest architecture in order to optimise Prime95. I also know from being a member of the prime search community for the last three years the amount of hard work George puts into the project. The PIII and Athlon processors have been around now for many months and indeed, taking a quick look at the stats, over 60% of members are using either a PIII, AMD or (unspecified type of) Celeron. Imagine the amount of extra work that could have been done if George would have been able to make a 20% speed increase for all these people say 6 months ago. I therefore suggest that a pay pal account (or similar) is set up. People who wished could easily donate a few dollars to make sure that George has available to him the latest architecture. I mean, come on, it wouldn't take too many 'couple of dollars' to buy the latest system board and processor with each new release of architecture and the benefits to the entire group would be immense. I hope George is not offended by this post and ask for discussion..... Regards, Lawrence...... <SNIP> >Are there any Athlon owners that would like to take a crack at >optimizing the v21 source so that Athlon owners can enjoy a speed boost too? >Alternatively, are there any Athlon owners in the Orlando area that might >be willing to let me use their machine sometime in the next month? _________________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers ------------------------------ End of Mersenne Digest V1 #863 ******************************
