Bug 10944

Summary: hrtimers and dyntick broken due tu lapic "not functionnal"
Product: Timers Reporter: Christian Casteyde (casteyde.christian)
Component: OtherAssignee: john stultz (john.stultz)
Status: CLOSED DOCUMENTED    
Severity: low CC: bunk
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.26-rc6 Subsystem:
Regression: Yes Bisected commit-id:
Bug Depends on:    
Bug Blocks: 10492    
Attachments: 2.6.25.6 dmesg log
2.6.26-rc6 dmesg log, with the lapic error

Description Christian Casteyde 2008-06-21 01:53:42 UTC 
Latest working kernel version: 2.6.25.6
Earliest failing kernel version: 2.6.26-rc6 or less
Distribution: Bluewhite64 (64 bits Slackware)
Hardware Environment: Athlon 64 X2, 64 bits
Software Environment: Dynticks, hrtimers activated in config
Problem Description:
It may very well be only a trace or a warning on something that never worked, but since 2.6.26 I got the following warnings in dmesg:

Clockevents: could not switch to one-shot mode: lapic is not functional.
Could not switch to high resolution mode on CPU 0
Clockevents: could not switch to one-shot mode: lapic is not functional.
Could not switch to high resolution mode on CPU 1

followed by:
Clockevents: could not switch to one-shot mode:<6>Clockevents: could not switch to one-shot
 mode: lapic is not functional.
Could not switch to high resolution mode on CPU 0
 lapic is not functional.
Could not switch to high resolution mode on CPU 1

These logs were not present with 2.6.25. They seem to indicate that lapic code is not working anymore in 2.6.26. I do not see any problem otherwise in using the kernel.

I append full 2.6.25 and 2.6.26 dmesg logs for analysis.

Steps to reproduce:
Maybe this is platform specific. I can do test and patch if necessary.
Comment 1 Christian Casteyde 2008-06-21 01:54:24 UTC 
Created attachment 16567 [details]
2.6.25.6 dmesg log

Lapic seems functionnal, as well as hrtimers on this version
Comment 2 Christian Casteyde 2008-06-21 01:54:47 UTC 
Created attachment 16568 [details]
2.6.26-rc6 dmesg log, with the lapic error
Comment 3 Christian Casteyde 2008-06-21 01:56:03 UTC 
btw, sorry, couldn't see that before because I was blocked by hardware reset sata_uli bug until yersterday and couldn't boot any 2.6.26 kernel
Comment 4 Thomas Gleixner 2008-06-21 11:37:49 UTC 
Command line differs. the 2.6.26 one has: nmi_watchdog=1

nmi_watchdog=1 disables the local apic timers and therefor highres/nohz

Try to use nmi_watchdog=2 instead.

Thanks,
       tglx