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**phil1349** · Apr 16, 2008, 04:18 PM

Re: Memory ussage after default installation.

This sounds quite normal.

Try (from main menu) System>Configuration>Kinfocenter and then Click memory from the drop menu on the left of the screen, this will give a graphic of memory usage.

This should have Application Data in red at the bottom, Disk Cache in dark green in the middle & Free memory at the top in light green. Probably Disk Cache is the widest band unless you have many applications running as using free memory like this as a cache significantly speeds up the system.

Contrast this with windoze which is so bloated that there is rarely any spare memory for a cache so it is slowwwwwww.....

**ZeuZ** · Apr 16, 2008, 05:10 PM

Re: Memory ussage after default installation.

Originally posted by phil1349

This sounds quite normal.

Try (from main menu) System>Configuration>Kinfocenter and then Click memory from the drop menu on the left of the screen, this will give a graphic of memory usage.

This should have Application Data in red at the bottom, Disk Cache in dark green in the middle & Free memory at the top in light green. Probably Disk Cache is the widest band unless you have many applications running as using free memory like this as a cache significantly speeds up the system.

Contrast this with windoze which is so bloated that there is rarely any spare memory for a cache so it is slowwwwwww.....

That's not even close to what I mean, Debian runs smoother than Kubuntu, on same hardware conditions, and leaving a buffer much minor.

I don't really need the graphics, command line is more than enough to answer that, and I allready posted the results

Thing goes as far as: 384mb are recomended, why is it taking 800++ on my system? There are no running services that I don't need in any runlevel, checked and double checked not only with rcconf and sysv-rc-conf but by actually checking the files to see if they were doubled at some place...

**dibl** · Apr 16, 2008, 06:29 PM

Re: Memory ussage after default installation.

Originally posted by ZeuZ

why is it taking 800++ on my system?

I don't see that, in your posted numbers. What do you think "Used" means, for Linux?

But, open the Konsole and run

Code:

top

and find out.

**ZeuZ** · Apr 16, 2008, 06:34 PM

Re: Memory ussage after default installation.

That's what TOP shows me also:

Code:

Mem:&#160; &#160; 963568k total,&#160; 928772k used,&#160; &#160; 34796k free,&#160; &#160; 49984k buffers
Swap:&#160; 1951824k total,&#160; &#160; 43292k used,&#160; 1908532k free,&#160; 352472k cached

Used equals not avaible, or in cache, or in buffer, so that:
used  - cache - buffer = really used memory.
Then It's taking 800++

EDIT: This also will clarify what you thought you viewed:

Code:

root@Deimos:~# free -m
         total    used    free   shared  buffers   cached
Mem:      940    921     19     0     51    346
-/+ buffers/cache:    523    417
Swap:     1906     42    1863

**dibl** · Apr 16, 2008, 06:40 PM

Re: Memory ussage after default installation.

Yep. So ... [928.8 Used - 352.5 Cached = 576.3 - 50 Buffers] = 526.3MB Really Used. Right? Or am I missing something?

p.s. just checked mine. It claims it is using 36% of 3.86GB, or about 1.3GB for applications. I've got a lot of stuff running ....

**kubicle** · Apr 16, 2008, 11:32 PM

Re: Memory ussage after default installation.

Originally posted by ZeuZ

root@Deimos:~# free -m
total used free shared buffers cached
Mem: 940 921 19 0 51 346
-/+ buffers/cache: 523 417
Swap: 1906 42 1863

The bold line tells the 'real' memory usage (excluding buffer/cache) = 523 used, 417 'free'

You should not worry about the 'free' memory used for buffer/cache, they make your computer run faster (not slower as the the buffer and cache are dynamically freed if applications need more memory). Ideally, you want linux to use all available memory (unused memory is wasted memory).

523 Mb is quite a bit of memory used by applications, but probably due to the multitude of applications you're running (as a comparison, my kubuntu machine generally uses about 250 Mb out of 1,5 Gb if I'm not doing anything memory intensive)

**ZeuZ** · Apr 17, 2008, 10:54 AM

Re: Memory ussage after default installation.

Originally posted by kubicle

Originally posted by ZeuZ

root@Deimos:~# free -m
total used free shared buffers cached
Mem: 940 921 19 0 51 346
-/+ buffers/cache: 523 417
Swap: 1906 42 1863

The bold line tells the 'real' memory usage (excluding buffer/cache) = 523 used, 417 'free'

You should not worry about the 'free' memory used for buffer/cache, they make your computer run faster (not slower as the the buffer and cache are dynamically freed if applications need more memory). Ideally, you want linux to use all available memory (unused memory is wasted memory).

523 Mb is quite a bit of memory used by applications, but probably due to the multitude of applications you're running (as a comparison, my kubuntu machine generally uses about 250 Mb out of 1,5 Gb if I'm not doing anything memory intensive)

Still it's annoying, I rather have memory free so that I do not inquire segmentation faults, and would like to uncache all that memory, or better said, prevet the system from taking all that into my cache...

**kubicle** · Apr 17, 2008, 01:34 PM

Re: Memory ussage after default installation.

Originally posted by ZeuZ

Still it's annoying, I rather have memory free so that I do not inquire segmentation faults

Could you elaborate that, buffers and cache shouldn't cause segfaults (faulty memory combs being the exception that comes to mind)

Here are a few links to information on memory management
http://gentoo-wiki.com/FAQ_Linux_Memory_Management
http://wiki.linuxquestions.org/wiki/...l_my_memory.3F

**ZeuZ** · Apr 17, 2008, 01:45 PM

Re: Memory ussage after default installation.

Problem comes when all my memory is occupied and it segmentates in between the SWAP and the RAM MEMORY.
Memorys are intact, as previously said, they work well with WinXPx64 and Debian, as long as with kFreeBSD those are the systems installed here. The problem only occurs with Kubuntu, and after having installed it. Because as a Live system it had even less than that occupied.. As live system, with OpenOffice open (I know, rather use Abiword) and emesene, and superkaramba, I had about 300mb occupied.

As for the FAQ, allready been there, and that's why I told my swappiness was not set high, like 20 only, as pointed in the Gentoo page tutorial, that has not been of any help.

**kubicle** · Apr 17, 2008, 02:56 PM

Re: Memory ussage after default installation.

Originally posted by ZeuZ

Memorys are intact, as previously said, they work well with WinXPx64 and Debian, as long as with kFreeBSD those are the systems installed here.

Originally posted by ZeuZ

and that's why I told my swappiness was not set high, like 20 only, as pointed in the Gentoo page tutorial, that has not been of any help.

Was this thread cut from another thread as I reread the posts to get all the information, but I couldn't find where you already mentioned it :P

You could try setting swappiness to 0 to see if it makes a difference, however there seems to be something fundamentally wrong with your installation/system if such a basic kernel operation as swapping causes segmentation faults.

It could be a kernel bug of course, but I haven't seen it on any of my machines, have you by any chance tried other versions of kubuntu?

Anyway, swapping/cache reducing when there's no free memory is something that should never lead to segmentation faults on a working system, so your basic problem is not that caches are too big, it's that the kernel seems to have trouble when it's supposed to dynamically free the memory. (freeing memory would be just a bandaid hiding the problem)

I'd still run memtest for some time just to be sure it's not hardware related, the memory defect could be subtle (that is not noticeable on low memory usage).

**ZeuZ** · Apr 17, 2008, 03:11 PM

Re: Memory ussage after default installation.

Now that I remeber, thanks to your notation, I had previously tried dapper, with same results... Then I just left it there, went to my debian, tried and adopted kFreeBSD and now again wanted to try back the new hardy... As for performance goes,everything seems quicker than previous, but my problem still concists... only with Kubuntu/Ubuntu (Haven-t tried Xubuntu yet)
I've been pointed from other places to think that way, it's not my own thought, IRC people (don't remember who actually) on ubuntu+1 told me something like that...
Then again, it's not memory fault, I'm totally sure of that.

Either way, me guess is just to reduce the buffering and see how it goes, is there any way to do that? Also perhaps recompiling the kernel to break that old limitation of 840mb, or is it allready set on Hardys kernel to allow low level memory managment up to 1gb?

**kubicle** · Apr 18, 2008, 03:26 AM

Re: Memory ussage after default installation.

Originally posted by ZeuZ

Then again, it's not memory fault, I'm totally sure of that.

I'll take your word for it

Either way, me guess is just to reduce the buffering and see how it goes, is there any way to do that?

This is a bit out of my area of 'expertise', but you might wish to check the settings in /proc/sys/vm/, you can list them with:

Code:

find /proc/sys/vm/* -print -exec cat '{}' \;

(You can find about what these settings do by googling the filename, for example "/proc/sys/vm/drop_caches"

Settings that at a quick glance seem relevant (although it might be useful to look up all of them) are drop_caches (echoing 1, 2 or 3 here should clear the caches)
http://linux-mm.org/Drop_Caches
and vfs_cache_pressure echoing >100 here should shrink caches more aggressively.

Read up before changing things.

NOTE: echoing new values requires a root shell (you can start a root shell with 'sudo su', 'sudo -i' or 'sudo -s'), if you're running a user shell redirection won't work with sudo (as the shell itself handles the redirection), you can of course do something like:

Code:

echo 3 | sudo tee /proc/sys/vm/drop_caches

in a normal user shell

Also perhaps recompiling the kernel to break that old limitation of 840mb, or is it allready set on Hardys kernel to allow low level memory managment up to 1gb?

The stock kernels are compiled with HIGHMEM enabled

**ZeuZ** · Apr 18, 2008, 10:00 AM

Re: Memory ussage after default installation.

Yes, I know, either way I sudoed and added a password I knew to root, so I'll just use 'su'

Well, now that's more likely what I'm after... Thanks for everything, will let you guys know how it went...

Oh, by the way, what process is the one that changes swappiness upon startup? I changed the file myself, but when I rebooted, it was back to the start...

EDIt: Nevermind, found it...

EDIT2: Well, drop_caches is set to 0, so cache is never cleaned?

**negora** · Apr 19, 2008, 04:13 AM

Re: Memory ussage after default installation.

First of all, I want to apologize the creator of this thread for using it to ask my doubt, but I think it's better this way instead of opening a new one. By the way, this is my first post here, althought I've been using/testing the Ubuntu family for some time ago (but I still am a semi-noob, he he he).

Well, looking for information about the crazy consumption of RAM on every installation which I've done of the Ubuntu familly (Kubuntu specially), I found this thread. It has been very useful to understand the behaviour of Linux about this matter. I like that way of thinking.

However, taking a look to the KSysGuard of KDE, I've started to doubt about more things...

I've 4 GB of RAM installed. It starts using 1 GB, and after a few hours working with Kubuntu it spends 2.5 - 3 GB aproximately (virtual memory at 0 KB always, even in heavy loads), with just the basic software running (the default services and background applications). Taking into account what's said here, it's normal because of that disk cache.

Taking a look to the consumption of every process independently, I've seen that some of them show some crazy figures. For example, just opening Firefox, it starts with ~551 MB :S , KMix ~128 MB, and many other "simple" background processes with 100 ~ 200 MB. Is included in that count per process the disk cache? Is this disk cache stored per application, depending on the use which every one does of files?

I understand that Linux stores a cache, but my common sense says that it should be counted apart of the consumption of every app, Right?

By the way, just to clarify, I install all my Ubuntu family tests with the "hd-media" installer. I doubt it has anything to do, but just in the case.

Thank you very much for your kindness and help

.

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