On 03/12/2018 13:35, Anup Patel 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 <a...@brainfault.org>
Hi Anup,
the GENERIC_SCHED_CLOCK dependency in the Kconfig is missing.
Thanks
> ---
> 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);
> +
> error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
> "clockevents/riscv/timer:starting",
> riscv_timer_starting_cpu, riscv_timer_dying_cpu);
>
--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog
