Bug 222513

Summary:	System performance slow/degraded when using power source on laptop
Product:	[openSUSE] openSUSE 10.2	Reporter:	Chris Bonner <cbonner>
Component:	Kernel	Assignee:	Thomas Renninger <trenn>
Status:	RESOLVED DUPLICATE	QA Contact:	E-mail List <qa-bugs>
Severity:	Major
Priority:	P5 - None
Version:	Beta 2
Target Milestone:	---
Hardware:	i686
OS:	Other
Whiteboard:
Found By:	Beta-Customer	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Chris Bonner 2006-11-19 00:15:59 UTC

On laptop performance is severely degraded when laptop is plugged into mains power supply. But not when runing off battery.

This seems to be a problem in the kernel as when booting even the kernel loading takes some time. Though if I unplug the power source everything speeds up.

Have had similar problems with Fedora 6. acpi=off fixes the problem with FC6. But with this option in 10.2, I just get a blank screen, and nothing happens.

By laptop is a Centrino 1.7Ghz 512MB RAM, and I believe an Asus motherboard.

Comment 1 Chris Bonner 2006-11-21 18:21:34 UTC

Booting with - acpi=off nosmp - fixes performance problem, but sound and networking is disabled.

Comment 3 Thomas Renninger 2006-12-01 09:37:27 UTC

acpi=off is a bad workaround, as your system will not scale the frequency dynamically (increase frequency when CPU has something to do and decrease frequency if CPU has nothing to do).
Per default, if you do nothing, the frequency should always be on lowest.
To check whether it works you can do:
cat /dev/zero >/dev/null
this should generate 100% load and the CPU must switch to highest freq.
You can monitor cpu frequency in another shell by doing:
watch -n1 cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq

There was a cpufreq bug fixed in about RC1/RC2. Can you retest with 10.2 final, pls.

Maybe some process is running and uses 100% CPU load when you go to battery mode. Please check with top and tell as the process running when your machine is switched up to highest freq when it should not.

Comment 4 Thomas Renninger 2006-12-13 13:57:34 UTC

This is probably a duplicate of:
bug #216205
Can you please also check top output whether sys and usr values are high, even no process is running, pls.

*** This bug has been marked as a duplicate of bug 216205 ***