mersenneforum.org  

Go Back   mersenneforum.org > Great Internet Mersenne Prime Search > Software

Reply
 
Thread Tools
Old 2005-02-10, 07:10   #1
A_Pryme
 
Feb 2005

25 Posts
Default Memory Allocation.

With nothing but Prime95 running on the computer would it be good to move the default 8mb of memory up to considerably more than the 25 I have it set at now? Does having it set at 25 limit it to 25? If the program needs more memory will it take more or restrict itself to 25? Is there a way to set Prime95 to freely access the memory as it wishes since it is the only program running on the machine anyway?

Total Physical Memory 512.00 MB
Available Physical Memory 291.96 MB

Total Virtual Memory 1.69 GB
Available Virtual Memory 1.31 GB
A_Pryme is offline   Reply With Quote
Old 2005-02-10, 08:08   #2
Uncwilly
6809 > 6502
 
Uncwilly's Avatar
 
"""""""""""""""""""
Aug 2003
101×103 Posts

23×1,187 Posts
Default

25 MB is fine for over 99% of what Prime95 does. The only time that it makes a difference is in stage 2 of P-1 factoring. Don;t worry about the amount unless you want to become P-1 obsessed.

NEVER make it so that Prime95 will tap into virtual memory. It slows things WAY down and gains nothing.
Uncwilly is offline   Reply With Quote
Old 2005-02-10, 12:08   #3
cheesehead
 
cheesehead's Avatar
 
"Richard B. Woods"
Aug 2002
Wisconsin USA

22·3·641 Posts
Default

Just to add a few details to Uncwilly's fine answer:

Quote:
Originally Posted by A_Pryme
Does having it set at 25 limit it to 25?
Yes.

Quote:
If the program needs more memory will it take more or restrict itself to 25?
The latter. It won't ask for more than you specify.

Quote:
Is there a way to set Prime95 to freely access the memory as it wishes since it is the only program running on the machine anyway?
Not the way I think you mean. All you can do is set higher specific limits -- which aren't needed or used for L-L testing -- There's no "use-as-much-as-you-want" setting.
cheesehead is offline   Reply With Quote
Old 2005-02-10, 20:03   #4
A_Pryme
 
Feb 2005

3210 Posts
Default

Quote:
Originally Posted by Uncwilly
25 MB is fine for over 99% of what Prime95 does. The only time that it makes a difference is in stage 2 of P-1 factoring.

I read that piece in the help file about memory. It seems that I only need to take memory into account when it gets to the P-1 factoring mode and the rest of the notes on memory usage are wrapped around a machine running multiple programs alongside of Prime95 or a dual processor machine.

This machine I use for this will run nothing but Prime95.

When Prime95 arrives at the P_1 factoring stage, will the 25 mb's of memory setting be sufficient for P-1 factoring or do I increase it when the machine arrives at that point? If it needs to be higher than 25 for P-1 factoring I would rather set the memory for that in advance and then just leave it alone.
A_Pryme is offline   Reply With Quote
Old 2005-02-10, 23:11   #5
Uncwilly
6809 > 6502
 
Uncwilly's Avatar
 
"""""""""""""""""""
Aug 2003
101×103 Posts

23·1,187 Posts
Default

Check out the "Setting Up Available Memory" section of the help file. In it you can find the following table:

[pre]exponent minimum reasonable desirable
6,000,000 12MB 23MB 33MB
10,000,000 19MB 36MB 53MB
33,000,000 65MB 125MB 185MB[/pre]
So, unless you wanted to be dedicated to doing a lot of P-1, I would suggest that you make 125 - 175 MB available, if you are not normally using the machine for any thing else.
Uncwilly is offline   Reply With Quote
Old 2005-02-11, 01:46   #6
A_Pryme
 
Feb 2005

25 Posts
Default

Quote:
Originally Posted by Uncwilly
[pre]exponent minimum reasonable desirable
6,000,000 12MB 23MB 33MB
10,000,000 19MB 36MB 53MB
33,000,000 65MB 125MB 185MB[/pre]
Where is the info on the current exponent being worked on or how do I find out wheter it is 6, 10, or 33 in order to increase the memory.

I would just as soon set the memory once instead of going back and forth resetting memory for different tasks.
A_Pryme is offline   Reply With Quote
Old 2005-02-11, 03:06   #7
Uncwilly
6809 > 6502
 
Uncwilly's Avatar
 
"""""""""""""""""""
Aug 2003
101×103 Posts

23×1,187 Posts
Default

What ever number you are running in Prime95, which is what you will see in the title bar of the window or in the window is the exponent. If you see a line like this:

[Feb 10 12:12] Iteration: 400000/22000001 [1.1%]. Per iteration time :1.101 sec.

The number that I put in bold would be your exponent. Since most of the numbers being handed out now are between 13,000,000 and 33,600,000; just set the memory for 150MB and forget about it. That do well for Prime95 for years to come.
Uncwilly is offline   Reply With Quote
Old 2005-02-12, 02:28   #8
patrik
 
patrik's Avatar
 
"Patrik Johansson"
Aug 2002
Uppsala, Sweden

52·17 Posts
Default

With your reported free memory (if you are doing nothing else on the computer) you may even set it to 250 MB. But if it starts slowing when you run stage 2, lower the setting.

As long as you are above the minimum setting stage 2 will run. Otherwise you might miss a small factor which would save you doing the long main primality test. (The P-1 test is done before the Lucas-Lehmer test starts.) Note: some numbers have already had the P-1 test done by someone else.
patrik is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
2 Memory Allocation Errors petrw1 PrimeNet 8 2018-01-13 09:00
Memory allocation pjaj Information & Answers 7 2011-02-12 02:57
"Memory allocation error" JuanTutors Software 25 2009-02-01 21:07
Memory Allocation Error joel893 Software 0 2008-06-03 14:54
Ram allocation JuanTutors Software 15 2004-08-30 01:15

All times are UTC. The time now is 12:01.

Wed Apr 21 12:01:34 UTC 2021 up 13 days, 6:42, 0 users, load averages: 2.56, 2.06, 1.84

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.