Re: 2.6.24-rc3-git3: usb hardware interrupts using 25% of CPU time

From: Tony Breeds
Date: Wed Nov 28 2007 - 17:40:34 EST


On Wed, Nov 28, 2007 at 10:33:18PM +0000, Frederik Himpe wrote:

> I installed Linux 2.6.24-rc3-git3 on a PPC based Apple Powerbook G4
> system. Now with top I see that over 20% of CPU time is used by hardware
> interrupts. Looking at /proc/interrupts, the number in the row
> ohci_hcd:usb1 is rising very quickly:

Hi Frederik,
Thanks for the report. We suspect that this is an accounting
problem introduced when powerpc enabled NO_HZ and highres timers.
Fortunatley from the testing we've done it doens't actually look like
the time is being spent in hardware interupts, just accounted for there.

Yours Tony

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