在 2006-07-26三的 16:41 +0200，stephan beal写道：
On Wednesday 26 July 2006 09:34, 张韡武 wrote:
Hello. Sorry if OT, I think this perhaps should go to suse-admin list The key point is to remove 'stun' effect and launch application faster with minimum budget. Option 5 can be taken only if all 1-4 cannot solve the two problems.
Get a second machine and migrate some of the users to it. 8 users running X11 on a single PC at once is a bit much, IMO.
It may sounds so but unless for some special reasons, actually 8 users can work together on one single server which is as powerful as today's normal desktop. This is because all the resource except memory needed by X terminal server do not scale "equally" with the the number of user grows. E.g. a machine has one single X11 user is fine, two users, fine too because both two people don't feel other user exist, the chance of doing CPU/disk intensive task at same moment is small. 3 people = feel the same. 4 people = feel the same. 5 people = feel the same, some times you may notice it's a bit slow 6 people ==> suddenly people feel the machine is noticeably slow 7 people ==> 'stun effect' become a trouble 8 people ==> very slow, complaints Have you noticed less then 5 people it makes almost no difference for speed? In my idea it means this configuration can handle 5 people. After upgrade, when number of user is less then 8 people, a single user cannot tell how many people are using the X11 terminal server by his/her feeling of respond time and speed, that means this machine can handle 8 people. Strange? That's how X terminal server differ from a FTP server or HTTP server, performance do not straightly go down with number of user grow, but when user number grow to some point, performance suddenly goes down. People do click on randomly and sometimes people are sitting there using only 1% cpu resource to write email like what I am doing now. It's pretty wasted to equip every user with a 2.8GHz desktop, plus the management trouble for helping users install the software they need and when SuSE upgrades, go to each users desktop in off-working hour to upgrade OS, help users backup their files. 1 machine is easier to manage then 8 machines, consider the stability of SuSE re-install OS after infected by virus is not necessary. The X terminal server is noticeably busy at 17:00 when everybody wish to save all the documents, send the last emails and finish today's job so that they go home without worrying a thing.
BTW, the reason for 'stun' effect I cannot understand. Why the machine 'stun'? When a user load a 500KB webpage, she is expecting to way a bit longer, she should wait for other users, she should get no more then 60% CPU resource and keep other people's console still usable but only slower.
i suspect that this is caused by resource locking issues in the shared libraries. i notice that when my g/f and i are both logged in to my machine (running 2 KDE sessions), apps like kmail seem to take notably longer to do anything at all. My *suspicion* (not backed up technically) is that it's a shared resource bottleneck somewhere in the KDE libs.
I am afraid the system resource is not assigned in a fair way.
It's not - 8 X11 sessions is too many, IMO.
I remember a long time ago I was sharing a Sparc desktop (using gnome) with several other people and we never had 'stun' problem, is sparc platform better on sharing?
Sparc is better at being "smooth" about concurrent logins, in my experience. e.g., a Sparc with 400MHz can out-perform a typical 1GHz PC when it comes to disk i/o.
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