Memory usage

[Matthew Flaschen]

Chris Miller wrote:
> On 3/6/07, Tez <binary_y2k2 at blueyonder.co.uk> wrote:
>> Leonardo de Miranda Cabral wrote:
>>> Hi all,
>>>
>>> I have a notebook with 1GB Ram memory. I was taking a look in the memory usage
>>> of this notebook and guess what, with almost nothing  (applications) loaded
>>> the memory that Kubuntu show as used with the 'free' command is 750MB.
>>> How????? I even stopped X (kdm), apache2, postgresql, everything... I`m
>>> getting crazy??!!! Why kubuntu don`t free this memory??? I went to a WinXP
>>> SP2 box with 512MB RAM that my father has and with a lot of application
>>> loaded it still hava free memory at about 200MB. For you guys help me lower
>>> my memory usage here a some 'free' and 'ps' outputs. [1] and [2] are outputs
>>> when nothing is loaded (neither X), and [3] and [4]  with some default
>>> applications that usually starts with kde. Is this a kernel bug??? If can any
>>> one help me or explain me this strange memory usage...
>>>
>>> ----------------- [1] -> free -m ---------------------------------------------
>>>              total       used       free     shared    buffers     cached
>>> Mem:          1002        761        240          0         36        659
>>> -/+ buffers/cache:         65        937
>>> Swap:         2933          0       2933
>>> -----------------------------------------------------------------------------------
>>>
>> _SNIP_
>> Do you see that most of the RAM is used under "cached" ?
>>
>> That's the file cache, where often accessed files are stored in RAM,
>> Take a look at my output of 'free -om':
>>              total       used       free     shared    buffers     cached
>> Mem:    1511       1414        97            0           24            873
>> Swap:   956           0           956
>>
>>
>> See how over 800MB is used as cache, it's normal for most of your RAM to
>> be cache, and it's actually a good thing to.
>> It saves the system having to access the, relatively slow, disk to read
>> some files.
>> As soon as the system needs more memory, it will shrink the cache to
>> free some.
>> If you want to see how much of the RAM is used by applications, just
>> take the cached amount from the used amount.
>> So in your case, 761 MB - 659 MB = 102 MB used
> 
> htop does this for you.
> 
> jstalin at the-kremlin$ ~/ sudo apt-get install htop

Cool program!  Looks better than KDE System Guard. :)

Matthew Flaschen