Most recent kernel where this bug did not occur: Not known Distribution: Debian Sid Hardware Environment: AMD Athlon64 San Diego 4000+ Software Environment: Tickless Timer Support (64bit CPU, but 32bit system) Problem Description: Every time if I activate the 'ondemand' powersave gorvener, dmesg reports following: Time: acpi_pm clocksource has been installed. Clocksource tsc unstable (delta = -245560788 ns) This thing needs at booting up ~ 2-10 seconds, which is a lot of time, so I think this is a bug. My kernel config with all my inbuilded powersave features etc. is in attached. Steps to reproduce: Just do a "/bin/echo 'ondemand' > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor".
Created attachment 11762 [details] My Kernel config
Some additional infos: the-me:~# cat /sys/devices/system/clocksource/clocksource0/available_clocksource acpi_pm pit jiffies tsc the-me:~# cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 55 model name : AMD Athlon(tm) 64 Processor 4000+ stepping : 2 cpu MHz : 1000.000 cache size : 1024 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow pni lahf_lm ts fid vid ttp bogomips : 2011.84 clflush size : 64
Can you boot up with clocksource=acpi_pm on the kernel command line please and check, whether the long boot time goes away. The "clock source unstable" message is _no_ BUG. The TSC is influenced by the CPU frequency and therefor considered unstable. That's a rule not a bug.
I added it to my kernel parameters, but it still appears. My grub entry: title Debian GNU/Linux, kernel 2.6.21.5 root (hd0,0) kernel /boot/vmlinuz-2.6.21.5 root=/dev/hda1 ro clocksource=acpi_pm initrd /boot/initrd.img-2.6.21.5
What does still appear ? The TSC unstable message or the boot slowness ?
Both.
Can you please try: http://www.tglx.de/projects/hrtimers/2.6.22-rc5/patch-2.6.22-rc5-hrt1.patch on top of 2.6.22-rc5, whether the problem persist or not.
Also please check, whether nohz=off or highres=off or nohz=off highres=off on the 2.6.21 kernel command line make any difference
With these commandlines, it's working. Bug I want to use a tickless kernel :(
With all of them ? even the highres=off one, where tickless is still active ?
Seems like only with the tickless one.
Seems to be fixed in 2.6.22-rc5. Thanks a lot :)