Messages in this thread | | | Subject | Re: [PATCH] sched: generalize CONFIG_IRQ_TIME_ACCOUNTING for X86 and ARM | From | Peter Zijlstra <> | Date | Mon, 27 Feb 2012 11:12:15 +0100 |
| |
On Mon, 2012-02-20 at 10:04 +0400, Dmitry Antipov wrote: > Generalize CONFIG_IRQ_TIME_ACCOUNTING between X86 and > ARM, move "noirqtime=" option to common debugging code. > For a bit of backward compatibility, X86-specific option > "tsc=noirqtime" is preserved, but issues a warning. > > Suggested-by: Yong Zhang <yong.zhang0@gmail.com> > Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk> > Suggested-by: Ingo Molnar <mingo@elte.hu> > Acked-by: Venkatesh Pallipadi <venki@google.com> > Signed-off-by: Dmitry Antipov <dmitry.antipov@linaro.org>
Thanks for Cc'ing me (maintainer) and Venki (original author of the stuff) :-)
> diff --git a/include/linux/sched.h b/include/linux/sched.h > index 7d379a6..9b13f79 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1961,13 +1961,16 @@ extern void sched_clock_idle_wakeup_event(u64 delta_ns); > #endif > > #ifdef CONFIG_IRQ_TIME_ACCOUNTING > -/* > - * An i/f to runtime opt-in for irq time accounting based off of sched_clock. > - * The reason for this explicit opt-in is not to have perf penalty with > - * slow sched_clocks. > - */ > -extern void enable_sched_clock_irqtime(void); > -extern void disable_sched_clock_irqtime(void); > +extern int sched_clock_irqtime; > +static inline void enable_sched_clock_irqtime(void) > +{ > + if (sched_clock_irqtime == -1) > + sched_clock_irqtime = 1; > +} > +static inline void disable_sched_clock_irqtime(void) > +{ > + sched_clock_irqtime = 0; > +} > #else > static inline void enable_sched_clock_irqtime(void) {} > static inline void disable_sched_clock_irqtime(void) {}
Please keep them out-of-line, its not a fast path and it avoids having to expose the state variable.
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 5255c9d..4e7a197 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -757,18 +757,21 @@ static DEFINE_PER_CPU(u64, cpu_hardirq_time); > static DEFINE_PER_CPU(u64, cpu_softirq_time); > > static DEFINE_PER_CPU(u64, irq_start_time); > -static int sched_clock_irqtime; > > -void enable_sched_clock_irqtime(void) > -{ > - sched_clock_irqtime = 1; > -} > +/* > + * -1 if not initialized, 0 if disabled with "noirqtime" kernel option > + * or after unstable clock was detected, 1 if enabled and active. > + */
You forgot to explain what you need the tri-state for.
> +__read_mostly int sched_clock_irqtime = -1; > > -void disable_sched_clock_irqtime(void) > +static int __init irqtime_setup(char *str) > { > sched_clock_irqtime = 0; > + return 1; > } > > +__setup("noirqtime", irqtime_setup); > + > #ifndef CONFIG_64BIT > static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
Other than that no real objections.. I guess.
| |