misbehaves with Linux' CPU hotplug/unplug

Submitted by Tomasz Torcz

Description

Please describe the problem: GNOME System Monitor is totally unaware of CPU Hotplug/Hotremove events. It also have problem with "sparse" cpu numbers.

Steps to reproduce: Scenario A:

Run System Monitor
Unplug CPU (echo 0 > /sys/devices/system/cpu/cpu1/online)

Scenario B:

Unplug CPU
Run System Monitor
Plug CPU (echo 1 > /sys/devices/system/cpu/cpu1/online)

Scenario C:

Run System Monitor on 4-way SMP system.
Unplug second or third CPU

Actual results: Scenario A: Unplugged CPU's line goes flat, but CPU is still displayed

Scenario B: Freshly plugged-in CPU do not appear in monitor.

Scenario C: SERIOUS! System Monitor shows only one (if second CPU was unplugged) or two (if third CPU) CPU's graphs. It doesn't show fourth (and third) CPU's graph.

Expected results: Scenario A: Unplugged CPU's label should be grayed-out and percent display should be changed to "offline".

Scenario B: Freshly plugged CPU should either: a) appear b) be un-grayed-out (see Scenario A expected action)

Scenario C: CPUs 3 and 4 should be shown even if CPU2 is disabled. System Monitor shouldn't stop enumerating CPUs on first offline one.

Does this happen every time? Yes.

Other information: Multicore laptops are becoming standard, and power management policy could turn off (unplug) unused CPUs. So this is rather imporant drawback in GNOME System Monitor.