[Bug 204144] [NEW] kde4 doesn't utilize mutiple available CPU cores

[Kevin Hunter]

Public bug reported:

Note: This bug report may be misplaced because I'm not sure to which
package/program to attribute the oversight/problem.  Is it a kernel
package I'm perhaps missing?  Nothing immediately jumped out at me while
perusing the kernel packages via Adept.

Setup:
Dell Vostro 1500, Core 2 Duo
Installed Hardy alpha 6, KDE4

To save someone 5 minutes of head scratching, I'll repeat: that's KDE4,
not KDE3. However, looking through the /etc/init.d/kdm script, I see
references to kde3, so not sure ...

Background: I have a Core 2 Duo at 2.2 GHz, with plenty of RAM.  That
means effectively 2 CPUs or cores.  While researching/preparing
https://bugs.launchpad.net/ubuntu/+source/kdebase-workspace/+bug/204136
, my kdm binary started hogging a core.  This still left a free
available core.  However, things noticeably slowed down.  For instance,
typing the previous bug report in Konqueror was slow.  On a single core
system I'd expect this, but on a dual-core system, with one core not
being utilized, I would expect to not immediately notice a hogging
process like that.

Symptom: KDE4 responsiveness gets noticeably slower when a process (in
this case, kdm) hogs a core, despite the fact that a second core is
barely being used.

Steps to reproduce:
0. Use a multi-core processor.  In this case, Intel based.
1. Login to a KDE4 session.
2. Get a process to go hog-wild and take 100% of a core.  (In this case, kdm, but I'm sure a busy wait loop will do the trick.)
3. Use the system.

Actual behavior:
General system slow down, becomes slow to respond to my inputs and to draw the screen.

Expected behavior:
Hog-wild broken behavior of kdm aside, I expect to notice a slow down if there's an unused core.  Programs ought to use the unused core.

** Affects: kdebase (Ubuntu)
     Importance: Undecided
         Status: New

-- 
kde4 doesn't utilize mutiple available CPU cores
https://bugs.launchpad.net/bugs/204144
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