BSD systems are known to have the highest uptime, but our favorite GNU/Linux system can do the same if we want. At work my computer runs since 260 days without any reboot thanks to Ubuntu (LTS 10.04).
This is cool, nevertheless having software launched for a long time consume a lot of memory (I like to keep terminals and emacs open to save history), especially Firefox uses one to three giga bytes of memory (even in version 30.0). Software not used everyday goes to swap and come back when needed. This process can slow my computer for minutes (when I unlock my session).
The only solution is to kill these applications and restart them properly. I used to track memory eaters with "top" command, but it's hard to see in one time which software is using most of memory.
I wanted to do it for long time, and now it's out ! I wrote a PERL script called memstats that list processes by memory usage (and not by CPU usage like top).
It reads information from /proc/PID/stat and /proc/PID/status, so it's very Linux dependant (sorry BSDs...).
memstats output looks like "top" (because it's a good one).
soutade@cybelle> memstats PID OWNER VIRT RES S TIME COMMAND 20098 soutade 3.10g 1.80g S 09:00:59 firefox 1285 root 526m 259m S 6214:00:04 Xorg 2555 soutade 862m 200m S 6214:00:10 gnome-terminal 2113 soutade 827m 181m S 6214:00:20 gnome-panel 20081 soutade 866m 153m S 10:00:12 thunderbird 2122 soutade 1.97g 98m S 6214:00:20 nautilus 2192 soutade 591m 86m S 6214:00:13 indicator-apple 20104 soutade 1.07g 42m S 09:00:58 pidgin 26536 soutade 627m 40m S 06:00:22 gedit 6517 soutade 529m 30m S 2816:00:40 emacs 2845 soutade 442m 27m S 00:00:50 emacs 22935 soutade 449m 23m S 103:00:06 emacs 2094 soutade 899m 23m S 6214:00:21 metacity 2207 soutade 393m 11m S 6214:00:13 indicator-messa 2762 soutade 114m 10m S 00:00:48 python 9752 soutade 401m 8m S 96:00:18 gnome-screensav 2070 soutade 766m 7m S 6214:00:22 gnome-settings- 2914 soutade 94m 6m R 00:00:00 memstats 2121 soutade 477m 6m S 6214:00:20 notification-da 2489 soutade 414m 6m S 6214:00:20 update-notifier 23305 soutade 391m 5m S 5641:00:44 ubuntuone-syncd 2280 soutade 418m 4m S 6214:00:10 gdu-notificatio 2061 soutade 22m 4m S 6214:00:22 dbus-daemon 1973 root 192m 4m S 6214:00:32 lightdm 6886 soutade 581m 4m S 3797:00:46 gnome-keyring-d 2134 soutade 539m 4m S 6214:00:19 gnome-fallback- 28423 soutade 85m 4m S 05:00:43 bash 2389 soutade 335m 4m S 6214:00:00 zeitgeist-daemo 6080 soutade 332m 4m S 3624:00:44 pulseaudio 2382 soutade 400m 3m S 6214:00:00 zeitgeist-datah
memstats is licenced under GNU GPL v3 and available in my inDefero forge. Have fun !