mersenneforum.org  

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

Reply
 
Thread Tools
Old 2021-06-11, 00:34   #1
Chuck
 
Chuck's Avatar
 
May 2011
Orange Park, FL

3×13×23 Posts
Default Does the PRP proof file cause disk fragmentation?

Does the preallocation of the large PRP proof file at the start of a PRP test contribute to disk fragmentation in Windows? I have watched as this file is created at the start of a run and it grows and grows until it reaches its full required size.

Is prime95 allocating the space all at once, or is it writing a portion at a time to reach the required size? I ask, since I have stopped prime95 a short ways into a new PRP test and run a Diskeeper optimization and there are a large number of free spaces consolidated.

Is it recommended to optimize each time a new PRP test created a new proof file?
Chuck is offline   Reply With Quote
Old 2021-06-11, 00:39   #2
kruoli
 
kruoli's Avatar
 
"Oliver"
Sep 2017
Porta Westfalica, DE

10101010002 Posts
Default

Creating and writing a file not on a low level always may cause fragmentation. On Linux at least, one (e.g. mprime) could use fallocate. I do not now which method is used internally.

Fragmentation should not cause problems until the proof will be generated. Even then I am not sure. How many fragments do you count? A few (i.e. < 100) should not cause a major slowdown.

Optimizing your system only because of Prime95/mprime is surely not recommended. If that would be the case, George likely would have to do some bug fixing...

Last fiddled with by kruoli on 2021-06-11 at 00:40 Reason: Grammar.
kruoli is online now   Reply With Quote
Old 2021-06-11, 00:47   #3
Chuck
 
Chuck's Avatar
 
May 2011
Orange Park, FL

3·13·23 Posts
Default

Quote:
Originally Posted by kruoli View Post
Fragmentation should not cause problems until the proof will be generated. Even then I am not sure. How many fragments do you count? A few (i.e. < 100) should not cause a major slowdown.
As I remember there were several thousand...but that was probably after several PRP runs had been done.
Chuck is offline   Reply With Quote
Old 2021-06-11, 00:54   #4
kruoli
 
kruoli's Avatar
 
"Oliver"
Sep 2017
Porta Westfalica, DE

68010 Posts
Default

Since the allocation should be done before the first residue is saved, this really might be a problem. But please check this back again.
kruoli is online now   Reply With Quote
Old 2021-06-11, 00:55   #5
retina
Undefined
 
retina's Avatar
 
"The unspeakable one"
Jun 2006
My evil lair

33·233 Posts
Default

IMO disk fragmentation is an overblown non-issue for most uses. Don't worry about it. Companies that make the defragmentation tools will of course say how awful it is and that you definitely need their stuff. But if it really was such a huge problem as they claim then the FS drivers would have it inbuilt.

In cases of extreme fragmentation things might go a bit slower, that is all. If you are really worried about it, once in a few months or so of running a defragmenter should be fine.

Last fiddled with by retina on 2021-06-11 at 00:56
retina is online now   Reply With Quote
Old 2021-06-11, 01:00   #6
kruoli
 
kruoli's Avatar
 
"Oliver"
Sep 2017
Porta Westfalica, DE

23×5×17 Posts
Default

Quote:
Originally Posted by retina View Post
IMO disk fragmentation is an overblown non-issue for most uses.
Yes, especially with an SSD drive. I forgot to ask about that.

At my work, my boss still likes to order HDDs as a boot drive. A lot of loading processes behave like having fragmentation (high counts of small files). I despise him for this.
kruoli is online now   Reply With Quote
Old 2021-06-11, 01:08   #7
Uncwilly
6809 > 6502
 
Uncwilly's Avatar
 
"""""""""""""""""""
Aug 2003
101×103 Posts

272B16 Posts
Default

If I recall correctly, it reserves the whole size and then files in as needed. There was discussion during the early stages about writing the files to do the certs and file allocation and SSD. You might try searching some of the threads about that.
Uncwilly is offline   Reply With Quote
Old 2021-06-11, 01:33   #8
Chuck
 
Chuck's Avatar
 
May 2011
Orange Park, FL

38116 Posts
Default

Quote:
Originally Posted by Uncwilly View Post
If I recall correctly, it reserves the whole size and then files in as needed. There was discussion during the early stages about writing the files to do the certs and file allocation and SSD. You might try searching some of the threads about that.
It writes the file to the full size before starting the test (I have watched this behavior in file manager). There is also a message in the program window "preallocating proof file".
Chuck is offline   Reply With Quote
Old 2021-06-11, 01:35   #9
Chuck
 
Chuck's Avatar
 
May 2011
Orange Park, FL

3×13×23 Posts
Default

Quote:
Originally Posted by kruoli View Post
Yes, especially with an SSD drive. I forgot to ask about that
I am running on a HDD.
Chuck is offline   Reply With Quote
Old 2021-06-11, 02:03   #10
Xyzzy
 
Xyzzy's Avatar
 
Aug 2002

5·1,663 Posts
Default

https://docs.microsoft.com/en-us/sys...wnloads/contig
Xyzzy is offline   Reply With Quote
Reply

Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Unexpected error during .proof file upload Raydex Software 4 2021-03-08 16:00
How do I get the ~133 mb proof file delivered to GIMPS in the manual environment? tsc Information & Answers 10 2020-11-23 23:34
[Help] Cannot open PRP proof interim residues file: n/p108897011.residues wagner85 Information & Answers 5 2020-11-16 03:02
memory fragmentation and GMP Chris Card Programming 0 2006-12-18 16:09
disk writes and results file outputs nostream Software 4 2005-07-16 10:12

All times are UTC. The time now is 07:22.


Thu Oct 28 07:22:23 UTC 2021 up 97 days, 1:51, 0 users, load averages: 1.84, 2.03, 2.05

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.