Messages in this thread | | | Date | Thu, 06 Dec 2018 12:32:23 -0800 (PST) | Subject | Re: [PATCH] clocksource: riscv_timer: Provide sched_clock | From | Palmer Dabbelt <> |
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On Mon, 03 Dec 2018 04:35:24 PST (-0800), anup@brainfault.org wrote: > Currently, we don't have a sched_clock registered for RISC-V systems. > This means Linux time keeping will use jiffies (running at HZ) as the > default sched_clock. > > To avoid this, we explicity provide sched_clock using RISC-V rdtime > instruction (similar to riscv_timer clocksource). > > Signed-off-by: Anup Patel <anup@brainfault.org> > --- > drivers/clocksource/riscv_timer.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c > index 084e97dc10ed..431892200a08 100644 > --- a/drivers/clocksource/riscv_timer.c > +++ b/drivers/clocksource/riscv_timer.c > @@ -8,6 +8,7 @@ > #include <linux/cpu.h> > #include <linux/delay.h> > #include <linux/irq.h> > +#include <linux/sched_clock.h> > #include <asm/smp.h> > #include <asm/sbi.h> > > @@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) > return get_cycles64(); > } > > +static u64 riscv_sched_clock(void) > +{ > + return get_cycles64(); > +} > + > static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = { > .name = "riscv_clocksource", > .rating = 300, > @@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n) > cs = per_cpu_ptr(&riscv_clocksource, cpuid); > clocksource_register_hz(cs, riscv_timebase); > > + sched_clock_register(riscv_sched_clock, > + BITS_PER_LONG, riscv_timebase);
Shouldn't this just be 64, not BITS_PER_LONG? We have 64-bit counters on RV32I.
> + > error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING, > "clockevents/riscv/timer:starting", > riscv_timer_starting_cpu, riscv_timer_dying_cpu);
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