Messages in this thread | | | Date | Mon, 21 Dec 2009 18:48:04 -0600 | From | Robert Hancock <> | Subject | Re: [2.6.33-rc1] System timer flooding bus on Lenovo Thinkpad W500 laptop in x86_64 |
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On 12/21/2009 12:12 PM, Shawn Starr wrote: > Hello kernel devs, > > I am noticing a serious problem with the system timer flooding the bus with > many interrupts for no reason. I have compiled the kernel with tickless > enabled. > > Can someone provide me some debugging to find out why this is happening? > > As a comparsion my quad core box has no such issue: (Running 2.6.32-rc7) > x86_64 > 0: 42 4 1 1 IO-APIC-edge timer
That's not really a fair comparison, that box is likely using the APIC timer (which will be on a different line) instead of the PC timer. Those 48 interrupts likely all occurred just after boot.
> > my Lenovo ThinkPad W500 (latest BIOS 3.11) laptop shows the system timer > flooding the bus (Running 2.6.33-rc1) x86_64 > 0: 66775 70429 IO-APIC-edge timer<-- keeps rising, rapidly > > and afew minutes ... > > 0: 119849 124505 IO-APIC-edge timer > > Same for Rescheduling interrupts rising just as fast with the timer. > > This does not look right, powertop shows: > > 40.0% ( 62.1)<kernel IPI> : Rescheduling interrupts > 22.9% ( 35.6)<interrupt> : extra timer interrupt > 17.0% ( 26.4)<interrupt> : iwlagn > > and another sample... > > 54.6% (144.8)<kernel IPI> : Rescheduling interrupts > 14.6% ( 38.8)<interrupt> : extra timer interrupt > 8.5% ( 22.6)<interrupt> : iwlagn > 6.5% ( 17.2)<interrupt> : uhci_hcd:usb6, radeon@pci:0000:01:00.0 > 6.5% ( 17.2) USB device 6-1 : Microsoft Basic Optical Mouse v2.0 > (Microsoft ) > > There is no cause for the rescheduling interrupts and extra timer interrupt to > wakeup the CPUs so much? Are there any timer issues?
Can you post full dmesg and /proc/interrupts output?
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