Review your favorite Linux distribution.
Go Back > Forums > Linux Forums > Linux - Software
User Name
Linux - Software This forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.


  Search this Thread
Old 11-05-2004, 09:47 AM   #1
Registered: Oct 2004
Location: still outside the Matrix
Distribution: Arch, formerly Gentoo and Slackware
Posts: 438

Rep: Reputation: 31
OOo memory use comparison

I have two versions of OpenOffice on my Slackware system. One is version 1.1.3 of the OpenOffice generic installation that I downloaded from the website. The other is a "KDE integration" version 1.1.1 that I compiled myself. I have a question about memory usage by these two versions of OpenOffice.

These results are from the KDE system guard applet. Each instance of OOo Writer is openied with a blank document.

OOo Writer generic (v. 1.1.3) uses memory as follows:

- Six separate processes, each using 52,300Kb of physical memory and 107,224Kb of virtual memory.

OOo Writer KDE-integration (v. 1.1.1) uses memory as follows:

- Five separate processes, each using 63,180Kb of physical memory and 123,884Kb of virtual memory.

I say "separate processes" because each process, though identical in memory use, is assigned a unique PID.

I'm wondering about total memory footprint, since OOo generic 1.1.3 runs six processes but OOo KDE 1.1.1 runs just five. Each of the OOo generic processes is about 20 percent smaller in terms of memory use, but, if I'm reading the monitor correctly, there are six of them running. If there really are six rather than five processes running, then the total memory use of OOo generic is a lot greater.

I'm wondering if there truly are this many separate processes running. I thought that perhaps there might be some sort of duplication in the report or something.

Can anyone clarify this for me, please?

Last edited by dhave; 11-05-2004 at 10:01 AM.
Old 11-05-2004, 12:07 PM   #2
Senior Member
Registered: Jun 2004
Posts: 2,553

Rep: Reputation: 53
since the multiple instances are most likely forks of the original
each child gets a copy of the original address space as virtual memory
but this means i think only the page table is coppied !!! at fork
linux uses essentially total virtual memory where each process has access to all memory
so the pointers in the childs page table don't become unique until a write (copy on write)
so once a child process writes to an address that page say 2 or 4m becomes a unique copy..
or takes up ram..
so if one of the child processes is there for instance to handle printing and no printing is done
it uses no memory......
the same can actually be said i think for even the parent process.
time i think time for everyone to think about ram in a new way rather than what's free and what's used.
you processors MMU memory management unit alocates tables out all ram (or even more than all 3Gigs) to every process. plus 1Gig to all kernel processes. MMU for 32 bit processor is 4Gigs wide

someone correct if i'm wrong on some point !

Last edited by foo_bar_foo; 11-05-2004 at 12:09 PM.
Old 11-06-2004, 02:28 AM   #3
Registered: Oct 2004
Location: still outside the Matrix
Distribution: Arch, formerly Gentoo and Slackware
Posts: 438

Original Poster
Rep: Reputation: 31
So, tell me if I've got this right: when five OOo processes are reported to be in memory, actually it's just that five different forks have reserved memory if they need it. Until a process actually needs the memory, it's available for use by other processes. But the original process has priority? Or something like that?

Thanks for taking the time to reply to my long post, by the way.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
OOo on FreeBSD thick_guy_9 *BSD 7 04-12-2005 12:09 PM
OOo PhuckFonix Mandriva 2 07-12-2004 02:54 AM
OOo PhuckFonix Linux - Software 1 07-11-2004 10:18 PM
OOo 2.0 Squall Linux - Software 1 02-03-2004 07:45 PM
Help!?! RH 8 Memory Mapping -High Memory-Virtural Memory issues.. Merlin53 Linux - Hardware 2 06-18-2003 04:48 PM > Forums > Linux Forums > Linux - Software

All times are GMT -5. The time now is 01:48 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration