Hi Stefan,
On Thu, 13 Jul 2023 at 08:17, Stefan Roese <s...@denx.de> wrote:
>
> This patch adds the new Kconfig option CONFIG_CYCLIC_RATELIMIT_US which
> defines the min allowed time after with a new call into the cyclic
> infrastructure is allowed. This results in a ratelimiting of the all
> functions hooked into the cyclic interface. As it's been noticed that on
> some platforms, that high frequent calls to schedule() (replaced from
> WATCHDOG_RESET) may lead to a performance degration.
>
> When a high frequent calling into schedule() is detected, a warning is
> logged only once to help indentify this frantic caller.
>
> Signed-off-by: Stefan Roese <s...@denx.de>
> Cc: Simon Glass <s...@chromium.org>
> Cc: Christophe Leroy <christophe.le...@csgroup.eu>
> ---
> common/Kconfig | 11 +++++++++++
> common/cyclic.c | 27 +++++++++++++++++++++++++--
> include/asm-generic/global_data.h | 1 +
> 3 files changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/common/Kconfig b/common/Kconfig
> index 42baca20a618..0611cce301a5 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -601,6 +601,17 @@ config CYCLIC_MAX_CPU_TIME_US
> takes longer than this duration this function will get unregistered
> automatically.
>
> +config CYCLIC_RATELIMIT_US
> + int "Sets the min time/delay in us after a new call into schedule is
> done"
> + default 100
1000 ?
> + help
> + The min allowed time after with a new call into the cyclic
> + infrastructure is allowed. This results in a ratelimiting of the
rate limiting
> + all functions hooked into the cyclic interface.
> + As it's been noticed that on some platforms, that high frequent
> + calls to schedule() (replaced from WATCHDOG_RESET) may lead to a
> + performance degration.
degradation
also below
> +
> endif # CYCLIC
>
> config EVENT
> diff --git a/common/cyclic.c b/common/cyclic.c
> index a49bfc88f5c0..c945ae55c965 100644
> --- a/common/cyclic.c
> +++ b/common/cyclic.c
> @@ -12,6 +12,7 @@
> #include <log.h>
> #include <malloc.h>
> #include <time.h>
> +#include <linux/bug.h>
> #include <linux/errno.h>
> #include <linux/list.h>
> #include <asm/global_data.h>
> @@ -109,8 +110,30 @@ void schedule(void)
> * schedule() might get called very early before the cyclic IF is
> * ready. Make sure to only call cyclic_run() when it's initalized.
> */
> - if (gd)
> - cyclic_run();
> + if (gd) {
> + uint64_t now;
Should be u64 in here I think.
> +
> + /*
> + * Add some ratelimiting to not call into the cyclic IF too
> + * ofter. As it's been noticed that on some platforms, that
> + * high frequent calls to schedule() (replaced from
> + * WATCHDOG_RESET) may lead to a performance degration.
> + */
> + /* Do not reset the watchdog too often */
join with above comment
> + now = timer_get_us();
> + if (time_after_eq64(now, gd->cyclic_next_call)) {
> + cyclic_run();
> + gd->cyclic_next_call = now +
> CONFIG_CYCLIC_RATELIMIT_US;
> + } else {
> + /*
> + * Throw a warning (only once) to help identifying
> + * frantic callers
> + */
> + WARN_ONCE(1, "schedule() called very often, now =
> %lld us next call at %lld us, dt = %lld us\n",
> + now, gd->cyclic_next_call,
> + gd->cyclic_next_call - now);
> + }
> + }
> }
>
> int cyclic_unregister_all(void)
> diff --git a/include/asm-generic/global_data.h
> b/include/asm-generic/global_data.h
> index a1e1b9d64005..af26ae4dfc65 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -484,6 +484,7 @@ struct global_data {
> * @cyclic_list: list of registered cyclic functions
> */
> struct hlist_head cyclic_list;
> + uint64_t cyclic_next_call;
> #endif
> /**
> * @dmtag_list: List of DM tags
> --
> 2.41.0
>
Regards,
Simon
