RAM use by Jaunty and Hardy

Steven Susbauer steven at too1337.com
Wed Jun 17 23:59:51 UTC 2009


Karl F. Larsen wrote:
> Steven Susbauer wrote:
>> Karl Larsen wrote:
>>> 	Here is top for both systems:
>>>
>>>
>>>
>>>
>>> This top on Jaunty after 24 hours.
>>>
>>> top - 16:08:49 up 23:54,  3 users,  load average: 0.10, 0.18, 0.14
>>> Tasks: 127 total,   3 running, 124 sleeping,   0 stopped,   0 zombie
>>> Cpu(s): 29.2%us,  5.0%sy,  0.0%ni, 65.4%id,  0.0%wa,  0.3%hi,  0.0%si,
>>> 0.0%st
>>> Mem:   1025636k total,   991852k used,    33784k free,   113360k buffers
>>> Swap:  1959920k total,      460k used,  1959460k free,   497364k cached
>>>
>>>         Notice that Jaunty is using 460K of swap which does slow it
>>> down. It appears that Jaunty needs a minimum of 2 GB of RAM.
>>>
>>>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>>>
>>>  5998 karl      20   0  243m 118m  26m R 21.6 11.9  44:56.74 firefox
>>>
>>>  2794 root      20   0  101m  46m 9984 S  7.3  4.6  15:12.50 Xorg
>>>
>>>  3538 karl      20   0  367m  53m  19m S  4.7  5.3   6:02.79
>>> thunderbird-bin
>>>  3599 karl      20   0 16644 2592 1404 S  0.7  0.3   0:28.55
>>> gnome-screensav
>>>  3498 karl      20   0 37864  15m 8892 S  0.3  1.6   6:14.83 gnome-panel
>>>
>>> 11887 karl      20   0  2448 1184  912 R  0.3  0.1   0:00.27 top
>>>
>>>     1 root      20   0  3084 1584  260 S  0.0  0.2   0:01.30 init
>>>
>>>     2 root      15  -5     0    0    0 S  0.0  0.0   0:00.00 kthreadd
>>>
>>>     3 root      RT  -5     0    0    0 S  0.0  0.0   0:00.00 migration/0
>>>
>>>     4 root      15  -5     0    0    0 S  0.0  0.0   0:04.35 ksoftirqd/0
>>>
>>>     5 root      RT  -5     0    0    0 S  0.0  0.0   0:00.00 watchdog/0
>>>
>>>     6 root      15  -5     0    0    0 S  0.0  0.0   0:00.14 events/0
>>>
>>>     7 root      15  -5     0    0    0 S  0.0  0.0   0:00.00 khelper
>>>
>>>     8 root      RT  -5     0    0    0 S  0.0  0.0   0:00.00 kstop/0
>>>
>>>     9 root      15  -5     0    0    0 S  0.0  0.0   0:00.00
>>> kintegrityd/0
>>>    10 root      15  -5     0    0    0 S  0.0  0.0   0:00.14 kblockd/0
>>>
>>>    11 root      15  -5     0    0    0 S  0.0  0.0   0:00.00 kacpid
>>>
>>> This is Hardy after just a few minutes with firefox also running:
>>>
>>>
>>> top - 10:55:05 up 4 min,  2 users,  load average: 0.90, 1.02, 0.47
>>> Tasks: 125 total,   3 running, 122 sleeping,   0 stopped,   0 zombie
>>> Cpu(s): 13.6%us,  3.3%sy,  0.0%ni, 81.4%id,  0.0%wa,  0.3%hi,  1.3%si,
>>> 0.0%st
>>> Mem:   1034328k total,   710052k used,   324276k free,    23948k buffers
>>> Swap:  1959920k total,        0k used,  1959920k free,   374040k cached
>>>
>>>         As you can see Hardy uses 0K of Swap: So it can work with just
>>> 1GB of RAM.
>>>
>>>
>>>
>>>
>>>
>>>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>>>
>>>  6045 root      20   0 74276  32m 8668 S  5.3  3.2   0:06.62 Xorg
>>>
>>>  6682 karl      20   0  194m  60m  22m R  4.7  6.0   0:06.73 firefox
>>>
>>>  6318 karl      20   0 38968  22m  13m S  0.7  2.2   0:02.66 gnome-panel
>>>
>>>  6319 karl      20   0 15200 2680 1784 S  0.7  0.3   0:00.32
>>> gnome-screensav
>>>  6387 karl      20   0 59192  29m 9344 S  0.7  3.0   0:07.08 compiz.real
>>>
>>>  6499 karl      20   0 18248 9636 6828 S  0.7  0.9   0:00.62
>>> gtk-window-deco
>>>  6622 karl      20   0 31244  17m  10m S  0.7  1.7   0:00.76 gedit
>>>
>>>  6644 karl      20   0 74644  20m  10m R  0.7  2.0   0:00.58
>>> gnome-terminal
>>>  6669 karl      20   0  2308 1120  852 R  0.7  0.1   0:00.16 top
>>>
>>>  6291 karl      20   0 39972   9m 7884 S  0.3  1.0   0:00.67
>>> gnome-settings-
>>>  6320 karl      20   0 72788  33m  13m S  0.3  3.3   0:05.45 nautilus
>>>
>>>     1 root      20   0  2844 1688  544 S  0.0  0.2   0:01.34 init
>>>
>>>     2 root      15  -5     0    0    0 S  0.0  0.0   0:00.00 kthreadd
>>>
>>>     3 root      RT  -5     0    0    0 S  0.0  0.0   0:00.00 migration/0
>>>
>>>     4 root      15  -5     0    0    0 S  0.0  0.0   0:00.00 ksoftirqd/0
>>>
>>>     5 root      RT  -5     0    0    0 S  0.0  0.0   0:00.00 watchdog/0
>>>
>>>     6 root      15  -5     0    0    0 S  0.0  0.0   0:00.02 events/0
>>>
>>> 73 Karl
>>>
>> It is normal for some things to be put in swap after a long amount of
>> time if they are not being used (swappiness is set to 60 by default),
>> you don't want an idle app using a ton of your ram when it is not doing
>> anything. I suggest you do a more equal comparison, rather than taking a
>> system that has been up for a longer time vs a freshly booted system.
>> Also, read about the swappiness setting, as it will influence how the
>> kernel uses swap: http://kerneltrap.org/node/3000 is a start - If you
>> don't want swap being used so much, you should lower the swappiness number.
> 
>> In both cases you still have free system memory, and you also have some
>> memory being used for buffers. This seems to show that your system is
>> not using swap due to running out of ram as you are assuming. I
>> guarantee you would notice this if it were the case, both in the
>> response of the system and the grinding of the hard drive.
> 
>> My system which runs some larger apps for long periods of inactivity
>> (Firefox, Thunderbird, Banshee for days on end) has swap in use after 5
>> days, but plenty of free ram. They are a little delayed in spinning up
>> again when I return to using them, but then purr along fine as they are
>> put back into ram.
> 
> 
> 	Sorry Top reports how much RAM and SWAP is used period! Jaunty uses
> much more RAM than Hardy, period!
> 
> 73 karl
> 
> 

I didn't say anything about that. You stated that Hardy doesn't use swap
therefore fits in 1gb while Jaunty doesn't. I quote:

>>>         Notice that Jaunty is using 460K of swap which does slow it
>>> down. It appears that Jaunty needs a minimum of 2 GB of RAM.
>>>         As you can see Hardy uses 0K of Swap: So it can work with
>>> just 1GB of RAM.

This is incorrect. Leave Hardy on for 24 hours and it will also likely
use some swap. Measuring different systems with different uptimes is not
a fair comparison. If you want a more fair comparison, measure a fresh
install of both after they have been on for around the same amount of
time. Also, there is not much chance that using 460k of swap will
noticeably slow down your system, unless you are trying to use whatever
small app is in the swap at that moment.

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