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Description of problem: My desktop is shared between two users. We are both always logged in. We will frequently switch from one user to the other using the key combination Ctrl + Alt + Fx. Usually after the first day, switching between users causes the newly shown desktop to respond extremely slowly. After some time (caching?) the desktop responds at normal speed. That is, until we switch to the other user. I am not sure what output to capture to help diagnose the issue. But if you instruct me to provide any information I would be glad to help. Version-Release number of selected component (if applicable): kernel-3.2.2-1.fc16.x86_64 How reproducible: 100% Steps to Reproduce: 1. Log in as one user, open applications 2. Log in as a second user, open applications 3. Let OS run for a day 4. Switch to other user using Ctrl + Alt + Fx 5. Notice desktop responds very slowly 6. After five minutes desktop responds at normal speed Actual results: Desktop is slower than it should be. Expected results: Desktop responds as normal when switching between users.
Sounds very much like you are running out of memory. Applications have moved to swap, and once you switch users it takes a while to switch the current user applications from swap space. The output of 'free' would verify. Remember, when you switch users, all of the other user applications are still in memory and with web browsers especially, the memory footprint can grow significantly over time.
Here is the output of free after experiencing this issue: $ free total used free shared buffers cached Mem: 4041576 3926236 115340 0 21120 236620 -/+ buffers/cache: 3668496 373080 Swap: 6160380 2850216 3310164 Output of the top sorted by memory usage: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1814 root 20 0 2958m 1.2g 2600 S 10.0 31.1 721:51.35 Xorg 6562 jon 20 0 1466m 421m 19m S 0.3 10.7 44:00.36 firefox 23508 laura 20 0 1048m 242m 18m S 1.3 6.1 1:40.59 firefox 2653 jon 20 0 1994m 186m 10m S 0.0 4.7 97:22.83 evolution 2201 jon 20 0 1946m 105m 14m S 3.3 2.7 249:44.06 gnome-shell > when you switch users, all of the other user applications are still in memory > and with web browsers especially, the memory footprint can grow significantly > over time. Understood. This lag between switching users makes the multi-user experience a serious drag. It is quite frustrating to switch users, then experience no desktop response for ~30-60s. I never recall experiencing such a delay until F16 (possibly F15). Does my system have a small amount of memory for the usage? Are the top memory users using more memory than expected? If there is any additional output I can capture to diagnose the issue, or possible memory leaks I would be happy to collect the data. Hardware profile: http://www.smolts.org/client/show_all/pub_621c77b7-dfc4-4b1f-b643-19efd5fbe185
There is nothing to diagnose, look at the amount of swap you have in use. It is clearly not enough memory to support 2 users without swapping. And things like firefox will keep growing the memory footprint over time. If you leave pages like facebook open, it can get insane. 4GB of memory is sufficient for single user desktop usage typically. Switching users you are probably going to want at least 6. Unfortunately this is a reality with "web 2.0" and not a Linux issue that can be easily resolved. Browsers eat memory in pretty much any OS.