I have a long-term problem with my Acer TravelMate 3002WTMi (Pentium-M 1.73Ghz, 512 MB RAM) and Xubuntu 11.10. Whenever load increases machine tends to slow down to the point that it's totally unresponsive (for 10-30 sec. intervals which is very annoying). It always happens when i.e. Gmail and Youtube tabs are open with a browser.. I've been running Linux on desktop machines with less memory but I don't recall having such problems, besides I chose to run Xubuntu so it's really hard to blame memory. Nevertheless OS reports this memory usage while ONLY running xterm and default desktop (after dropping VM caches):
pkug@travelmate:~$ free -m
total used free shared buffers cached
Mem: 423 155 267 0 7 70
-/+ buffers/cache: 77 345
Swap: 500 67 433
Meanwhile process monitor tells that Xfce itself eats just around ~17 MB. Sometimes I don't get why so much memory is used when just doing nothing. Back to the original issue, is there anything I can do to prevent such slow downs ? I tried using different block scheduler, stuff like zramswap, tuning filesystem with data=writeback, experimenting with vm.swappiness (currently it's set to 10).. not much of a help. Here are the disk performance results:
pkug@travelmate:~$ sudo hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 1624 MB in 2.00 seconds = 812.32 MB/sec
Timing buffered disk reads: 102 MB in 3.05 seconds = 33.48 MB/sec