Mersenne Digest Thursday, December 9 1999 Volume 01 : Number 669
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Date: Mon, 06 Dec 1999 23:18:43 -0800
From: Luke Welsh <[EMAIL PROTECTED]>
Subject: Mersenne: Testing M(110503)
How quickly can M(110503) be tested now-a-days on the fastest
machines?
- --Luke
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Date: Tue, 07 Dec 1999 10:47:12 -0500
From: Bill Daly <[EMAIL PROTECTED]>
Subject: Re: Mersenne: questions
>> why is f(0) in an ll test = 4
The value of f(0) must be such that f(0)-2 is a quadratic residue mod Mp
and f(0)+2 is a quadratic nonresidue mod Mp. 4 is the smallest value
which works for all p; 10 is the next, followed by 52. You could use
f(0) = 3 provided that 5 is a quadratic nonresidue mod Mp, which will be
the case when p = 3 mod 4, but 3 will not work when p = 1 mod 4. There
are some numbers, e.g. 6, which never work. The precise reasoning behind
this is a bit too complicated for a short reply.
Regards,
Bill
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Date: Tue, 07 Dec 1999 13:57:58 -0500
From: Jeff Woods <[EMAIL PROTECTED]>
Subject: Mersenne: Comparitive bench, please?
I have a P-II/233 running NT 4.0 that I think is severely
underperforming. It has 256 MB of RAM, and much of it remains free. Some
applications take literally MINUTES to load, and I suspect a CPU problem,
although PrimeNT reports no calculation errors. I suspect that the CPU is
simply underclocked for some unknown reason -- the fan is working properly.
It is taking 1.788 seconds per iteration for exponents in the 8,290,000 range.
Could someone else who has a machine similar to this let me know if that is
an unreasonably high time per iteration? It doesn't have to be an
identical machine, but one reasonably close.
I have another machine, which is a P-II/333, but much more heavily laden
(PDC, MRTG every 5 minutes, network service monitoring, and constant
downloading via Internet, full board at 1Mbps.... and it is doing an 8.4MM
exponent at 0.435 per iteration. Is a 233 REALLY 4 times slower than a
heavily loaded 333?
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Date: Tue, 7 Dec 1999 14:12:49 -0600
From: "Pardoe, Richard (PRDR)" <[EMAIL PROTECTED]>
Subject: RE: Mersenne: Comparitive bench, please?
I have a Pentium 232 running NT 4.0 with only 96 MB of RAM that is getting
about 0.6 seconds per iteration for an exponent in the 8,490,000 range.
It might be worthwhile to look in the Task Manager to see what is using the
CPU time. My CPU is typically mid-90% of the time w/ Prime95.
Rich
- -----Original Message-----
From: Jeff Woods
I have a P-II/233 running NT 4.0 that I think is severely
underperforming. It has 256 MB of RAM, and much of it remains free.
...
It is taking 1.788 seconds per iteration for exponents in the 8,290,000
range.
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Date: Tue, 07 Dec 1999 17:04:56 -0500
From: Jeff Woods <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Comparitive bench, please?
No, it shows the NTPrime service taking 98% of the CPU time. I've run
benches on it, too, and it is just plain running slow, like a 66 Mhz or
slower machine.... I'll be looking for that compatibility mode thing shortly.
At 03:11 PM 12/7/99 -0500, you wrote:
>On Tue, 7 Dec 1999, Jeff Woods wrote:
>
> > I have a P-II/233 running NT 4.0 that I think is severely
> > underperforming. It has 256 MB of RAM, and much of it remains
> free. Some
> > applications take literally MINUTES to load, and I suspect a CPU problem,
> > although PrimeNT reports no calculation errors. I suspect that the CPU is
> > simply underclocked for some unknown reason -- the fan is working properly.
> >
> > It is taking 1.788 seconds per iteration for exponents in the 8,290,000
> range.
> >
> > Could someone else who has a machine similar to this let me know if
> that is
> > an unreasonably high time per iteration? It doesn't have to be an
> > identical machine, but one reasonably close.
>
>Jeff,
>
>Sounds to me as if something is wrong with the PII-233. I have a pretty
>lightly loaded PII-266 machine with 128MB RAM running WinNT 4 (SP3) that
>is getting iteration times of .398 on an exponent around 8.4 million.
>
>Does task manager show some other process stealing cycles from Prime95?
>
>Kel
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Date: Tue, 7 Dec 1999 17:05:15 -0500 (EST)
From: Chip Lynch <[EMAIL PROTECTED]>
Subject: RE: Mersenne: Comparitive bench, please?
My 233 is running much better than your 1.788 as well. A few million
things come to mind...
First, are you running the newest software? Prime95 is up to, what...
19.0.2? Something like that... I'm sure it's on the page. Also, if
you're in a Microsoft environment, Richard's right... check for things in
the Task Manager. "FindFast" is a Microsoft program that likes to eat CPU
time, and can be removed from the "StartUp" folder if it's on your system.
On the more obscure side of things, I just upgraded my motherboard, and
had to do a lot of manual settings to get it to work 'efficiently' with my
233. A 233 is running a 66Mhz clock at a 3.5 multiplier rate... the
motherboard I got (an Iwill motherboard) defaulted to something else, and
it wasn't readily obvious that this was the problem. (Okay, it was
readily obvious if you read the manual, but come on, who does that?).
I/O isn't an issue with this software, but you may want to check your
cache (L1 and L2), perhaps by disabling/enabling it in the bios to see how
that affects performance, and you may want to download some benchmark
programs (ZDNet has some good ones, I believe) to check your cache and Ram
speeds.
Generally those are the problems I find causing software to run poorly.
- ---Chip
On Tue, 7 Dec 1999, Pardoe, Richard (PRDR) wrote:
> I have a Pentium 232 running NT 4.0 with only 96 MB of RAM that is getting
> about 0.6 seconds per iteration for an exponent in the 8,490,000 range.
>
> It might be worthwhile to look in the Task Manager to see what is using the
> CPU time. My CPU is typically mid-90% of the time w/ Prime95.
>
> Rich
>
> -----Original Message-----
> From: Jeff Woods
>
> I have a P-II/233 running NT 4.0 that I think is severely
> underperforming. It has 256 MB of RAM, and much of it remains free.
> ...
> It is taking 1.788 seconds per iteration for exponents in the 8,290,000
> range.
>
>
> _________________________________________________________________
> Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
> Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
>
\\ ^ //
(o o)
---oOO--(_)--OOo------------------------------------
| Chip Lynch | Computer Guru |
| [EMAIL PROTECTED] | |
| (703) 465-4176 (w) | (202) 362-7978 (h) |
----------------------------------------------------
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------------------------------
Date: Tue, 07 Dec 1999 17:26:04 -0500
From: Jeff Woods <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Comparitive bench, please?
DING! Give that man a ceegar! While I didn't find a setting for
anything like that anywhere in the BIOS, I took a risk and let the BIOS
reconfigure itself for "optimal settings" in the hopes it wouldn't FUBAR
everything.... and the system is back to its snappy old self
again... Thanks, Jud!
At 03:01 PM 12/7/99 -0500, you wrote:
>At 01:57 PM 12/7/99 -0500, you wrote:
>
>>I have a P-II/233 running NT 4.0 that I think is severely
>>underperforming. It has 256 MB of RAM, and much of it remains
>>free. Some applications take literally MINUTES to load, and I suspect a
>>CPU problem,
>
>
>I don't know much about NT systems, but my father recently had a machine
>that was running extremely slowly. I finally found the problem - in the
>setup, it had inadvertently set to run at "compatibility speed", which is
>very slow. That could be the problem.
>
>
>+----------------------------------------------------------+
>| Jud McCranie |
>| |
>| Where a calculator on the ENIAC is equipped with 19,000 |
>| vacuum tubes and weighs 30 tons, computers in the future |
>| may have only 1,000 vacuum tubes and perhaps only weigh |
>| 1.5 tons. -- Popular Mechanics, March 1949. |
>+----------------------------------------------------------+
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------------------------------
Date: Tue, 07 Dec 1999 17:40:15 -0500
From: Jeff Woods <[EMAIL PROTECTED]>
Subject: Re: Mersenne: Comparitive bench, please?
Thanks to all who answered!
At 10:23 PM 12/7/99 +0000, you wrote:
>Assuming the processor in your 233 system really is a PII, you would
>seem to have a slow clock (perhaps it's running in doze mode?
This seems to have been it. <SOMETHING in the BIOS was slowing it down,
in any case). It is definitely a true P-II/233, verified by several
benchmark programs.
>Check
>the BIOS settings & disable power-saving) or another application
>running at a normal or high priority chewing up the majority of the
>available CPU time (check the NT Task Manager, which can be brought
>up using CTRL+ALT+DEL when running a normal Windows session. Really!)
I'm nearly MCSE certified (one test to go), so this, I knew.... I'd already
confimed that the CPU was popping at 100%, 96% or so of it by NTPrime. It
HAD to be underclocking somehow, and it was. Dunno WHAT it was, but it
was, because allowing the BIOS to save settings for "optimum performance"
was all that was needed.
>Also check the processor type in Prime95/NTSetup Options. If you have
>set the CPU type to something else, then the clock timings reported
>by Prime95 will be wrong, since they're obtained from the tick count
>divided by the processor speed.
I wasn't going on that report. (I run the NT Service version, so that info
from the screen is not available in any case). I did it by "doing the
math" -- stopping the service to put a "progress report" into the
results.txt file, then restarting it and letting it run for an hour, then
restopping it. Simple division with seconds elapsed versus iterations
during that hour yields the time per iteration. You have to do this for
longer than a few seconds, though, to get a good report. However, in
addition to the overall slow performace of the machine while in use, this
is what tipped me off, from my individual accounts report (edited to 80
chars per line):
prime fact current days date date
exp. bits iterat. run togo exp. updated assigned computer ID
- ------- ---- ------- ---- ---- ---- --------------- --------- ----
8297941 63 4390912 91.8 93.7 60.7 07-Dec-99 14:30 07-Sep-99 SKYWALKER
8591381 64 6815743 60.0 14.9 60.9 07-Dec-99 19:43 08-Oct-99 PALPATINE
Palpatine is a Pentium/200 (not even a P-II). Skywalker is the P-II in
question. All other machines are running at a normal speed, as well, but
this one seemed a bit pokey...
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------------------------------
Date: Tue, 07 Dec 1999 19:24:15 -0800
From: Spike Jones <[EMAIL PROTECTED]>
Subject: Mersenne: fantasy about blue gene
Suppose Blue Gene were to be turned on the task
of GIMPSing. To my knowledge, there is no way to
get a million one-gigahz processors to work as one
petaflop machine, so we would not get a residual
of a ~2^8E6 Mersenne in 1.5 seconds, but we *could*
theoretically give it a million exponents and get the
first ones back a couple weeks later, and have all
million back within five months, in which we could
expect ~4 new Mersenne primes, representing
38 years of our efforts, currently. Wouldnt that
be kewalllll. {8-] spike
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Date: Wed, 08 Dec 1999 08:38:38 +0000
From: Gordon Spence <[EMAIL PROTECTED]>
Subject: Mersenne: World's Fastest Computer???
So how do we get to beg, borrow or steal time on this monster...
http://www.pcworld.com/pcwtoday/article/0,1510,14151,00.html
G
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Date: Wed, 08 Dec 1999 11:35:45 +0100
From: Reto Keiser <[EMAIL PROTECTED]>
Subject: Mersenne: new (third) facotor of M(M(31))
hi all
i've found a new factor of M(M(31)) using Mfac 2.27. i am not
absolutely sure if it was already found by someone else, but with regard
to Will Edgingtons list, the factor isn't found yet.
The factor is 242557615644693265201 ( 2*k*M31 +1 )
using a k of 56474845800 ( 112949691600 ( 2*k in Mfac ))
cheers
Reto
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Date: Wed, 08 Dec 1999 17:45:54 +0100
From: Alexander Kruppa <[EMAIL PROTECTED]>
Subject: Re: Mersenne: World's Fastest Computer???
Gordon Spence wrote:
>
> So how do we get to beg, borrow or steal time on this monster...
>
> http://www.pcworld.com/pcwtoday/article/0,1510,14151,00.html
If they need code for a test drive, I could make a suggestion here..
hey, if David can do it..
Ciao,
Alex.
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Date: Thu, 9 Dec 1999 00:36:58 +0000
From: Tony Forbes <[EMAIL PROTECTED]>
Subject: Re: Mersenne: new (third) facotor of M(M(31))
Reto Keiser <[EMAIL PROTECTED]> writes
>hi all
>
>i've found a new factor of M(M(31)) using Mfac 2.27. i am not
>absolutely sure if it was already found by someone else, but with regard
>to Will Edgingtons list, the factor isn't found yet.
>
>The factor is 242557615644693265201 ( 2*k*M31 +1 )
>
>using a k of 56474845800 ( 112949691600 ( 2*k in Mfac ))
>
Congratulations and well done! It's certainly new to me.
- --
Tony
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Date: Thu, 9 Dec 1999 07:31:17 -0000
From: "Brian J. Beesley" <[EMAIL PROTECTED]>
Subject: Mersenne: Europe database /software mirror
I regret that the mirror site lettuce.edsc.ulst.ac.uk will be offline
from 16:00 GMT Friday 10th December until 09:00 GMT Monday 13th
December due to essential maintainance to the electricity supply in
the building in which it lives.
Regards
Brian Beesley
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End of Mersenne Digest V1 #669
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