Messages in this thread | | | Date | Thu, 10 Nov 2005 22:04:58 +0100 | From | Ingo Molnar <> | Subject | Re: IO-APIC problem with 2.6.14-rt9 |
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* john stultz <johnstul@us.ibm.com> wrote:
> > > //#define ARCH_HAS_READ_CURRENT_TIMER 1 > > > > > > to: > > > > > > #define ARCH_HAS_READ_CURRENT_TIMER 1 > > > > > > ? > > > > It works !! Thanks Ingo for the immediate response > > Hrm. Could you post the value for BogoMIPS that you're getting now? > > My patches touch the __delay() code, since using the TSC based delay > has just as many, if not more, problems as the loop based delay. So I > want to be careful that my changes are not further causing problems. > > Ingo, did you commented out ARCH_HAS_READ_CURRENT_TIMER because of > problems with the new calibration code?
yes. traces show that the new calibration code results in a bogomips value on Athlon64 CPUs that halve the timeout. I.e. udelay(100) now takes 50 usecs (!). The calibration code seems to assume the number of cycles == number of loops in __delay() - that is not valid. The calibration needs to happen based on some real clock, such as the PIT, or PIT-driven jiffies.
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