Messages in this thread | | | Date | Thu, 10 Nov 2016 14:51:47 -0800 | From | Bin Gao <> | Subject | Re: Re: [PATCH 1/2] x86/tsc: add X86_FEATURE_TSC_KNOWN_FREQ flag |
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> > --- a/arch/x86/kernel/tsc.c > > +++ b/arch/x86/kernel/tsc.c > > @@ -1283,10 +1283,10 @@ static int __init init_tsc_clocksource(void) > > clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP; > > > > /* > > - * Trust the results of the earlier calibration on systems > > - * exporting a reliable TSC. > > + * When TSC frequency is known (generally got by MSR or CPUID), we skip > > + * the refined calibration and directly register it as a clocksource. > > */ > > - if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) { > > + if (boot_cpu_has(X86_FEATURE_TSC_KNOWN_FREQ)) { > > This causes a regression, because with only this patch applied the architectures which use the reliable flag for this today are not longer taking this path. > > The proper thing to do here is to make this: > > if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE) || > boot_cpu_has(X86_FEATURE_TSC_KNOWN_FREQ)) { > > and remove the RELIABLE flag ckeck after the existing users are converted.
I Will fix this in next revision.
> Thanks, > > tglx >
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