You have to check if 'CONFIG_NO_HZ' is set to Y. Important: If you are using a kernel older than 2.6.21 this feature won't be available. Until now it is not available on 64-bit system like Intels Core 2 or AMDs k8, though there are already patches available ( I think they can be found at http://www.tglx.de/projects/hrtimers/ , but I'm not 100% sure if those are the right ones ). This feature is expected to be available for 64-bit as of kernel 2.6.23.
Peter On Sun, 2007-05-27 at 11:29 +0200, Antoine Caillau wrote: > Hi > > how can I check if my kernel is tickless. What is the kernel option ? > > Thanks for your answer, > > Antoine > > On 27/05/07, Peter Ganzhorn <[EMAIL PROTECTED]> wrote: > Are you running a tickless kernel? > I'd guess that the "extra timer interrupt" is the former timer > interrupt, which will cause 1000 wakeups if you're running a > 1000hz > kernel. Tickless kernels do not wake up because of that > interrupt. > > Your CPU has only 1 ms in C3 state - this could be caused by a > 1000hz > kernel as well, because it will wake up every ms. > > Peter > > > On Sun, 2007-05-27 at 10:36 +0200, Antoine Caillau wrote: > > Hi, > > > > Since 1.4 (or may be 1.3, I do not tested) I've a process > who wake up > > my CPU a lot. It is called "extra timer interrupt". Can > anyone tell me > > what it is ? > > > > Thanks a lot for your help. > > > > Antoine > > > > PowerTOP version 1.4 (C) 2007 Intel Corporation > > > > Cn Avg residency (5s) Long term residency avg > > C0 (cpu running) (19.6%) > > C1 0.0ms ( 0.0%) 0.0ms > > C2 3.4ms ( 3.7%) 2.2ms > > C3 1.0ms (76.7%) 1.0ms > > > > > > Wakeups-from-idle per second : 815.9 > > Power usage (ACPI estimate) : 11.3 W (5.4 hours left) > > > > Top causes for wakeups: > > 95.6% (1166.6) <interrupt> : extra timer interrupt > > 1.1% ( 13.8) <interrupt> : ohci1394, ipw3945 > > 0.7% ( 8.8) <interrupt> : ehci_hcd:usb1, > uhci_hcd:usb2 > > 0.3% ( 3.4) <kernel module> : usb_hcd_poll_rh_status > > (rh_timer_func) > > 0.3% ( 3.4) pcscd : do_nanosleep > (hrtimer_wakeup) > > 0.2% ( 2.8) powersaved : queue_delayed_work_on > > (delayed_work_timer_fn > > ) > > > > _______________________________________________ > > Power mailing list > > [email protected] > > http://www.bughost.org/mailman/listinfo/power > > _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
