From: Thomas G. <tg...@li...> - 2007-10-29 22:18:05
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On Mon, 29 Oct 2007, Glauber de Oliveira Costa wrote: CC'ed John and removed glauber@t60.localdomain :) > From: Glauber de Oliveira Costa <glauber@t60.localdomain> > > tsc is very good time source (when it does not have drifts, does not > change it's frequency, i.e. when it works), so it should have its rating > raised to a value greater than, or equal 400. > > Since it's being a tendency among paravirt clocksources to use values > around 400, we should declare tsc as even better: So we use 500. > > This patch also touches the comments on clocksource.h, which suggests > that 499 would be a limit on the rating values. > > Signed-off-by: Glauber de Oliveira Costa <gc...@re...> Acked-by: Thomas Gleixner <tg...@li...> > --- > arch/x86/kernel/tsc_32.c | 2 +- > arch/x86/kernel/tsc_64.c | 2 +- > include/linux/clocksource.h | 2 +- > 3 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c > index 9ebc0da..4d91e59 100644 > --- a/arch/x86/kernel/tsc_32.c > +++ b/arch/x86/kernel/tsc_32.c > @@ -280,7 +280,7 @@ static cycle_t read_tsc(void) > > static struct clocksource clocksource_tsc = { > .name = "tsc", > - .rating = 300, > + .rating = 500, > .read = read_tsc, > .mask = CLOCKSOURCE_MASK(64), > .mult = 0, /* to be set */ > diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c > index 9c70af4..4fd5b1b 100644 > --- a/arch/x86/kernel/tsc_64.c > +++ b/arch/x86/kernel/tsc_64.c > @@ -262,7 +262,7 @@ static cycle_t __vsyscall_fn vread_tsc(void) > > static struct clocksource clocksource_tsc = { > .name = "tsc", > - .rating = 300, > + .rating = 500, > .read = read_tsc, > .mask = CLOCKSOURCE_MASK(64), > .shift = 22, > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h > index 107787a..5b0aadd 100644 > --- a/include/linux/clocksource.h > +++ b/include/linux/clocksource.h > @@ -39,7 +39,7 @@ struct clocksource; > * A correct and usable clocksource. > * 300-399: Desired. > * A reasonably fast and accurate clocksource. > - * 400-499: Perfect > + * >= 400 : Perfect > * The ideal clocksource. A must-use where > * available. > * @read: returns a cycle value > -- > 1.5.0.6 > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to maj...@vg... > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > |