[PATCH 2/2] cyclic: parse cyclic list only if next cyclic timestamp is reached

[Marek Vasut]

On 7/2/26 5:24 PM, Patrice Chotard wrote:
> On STM32MP157C-DK2, when using the "ums" command, in sleep_thread(),
> ctrlc() is called every ~640ms which doesn't allows high reactivity when
> user press CTRL+C in U-Boot console.
> 
> In sleep_thread() loop, ctrlc() is called every 200000 iterations.
> But schedule is called on each loop iteration.
> 
> Optimize cyclic_run() in order to parse the cyclic list only is the
> next cyclic to run is due.
> During cyclic list parsing, save the nearest cyclic timestamp, which
> allows to exit from next cyclic_run() call if no cyclic will be executed.
> 
> This allow to save computation time :
>    _ before : ctrlc() is called every ~640ms
>    _ after  : ctrlc() is called every ~230ms
> 
> Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
> Cc: Marek Vasut <marek.vasut at mailbox.org>
> ---
>   common/cyclic.c                   | 12 ++++++++++++
>   include/asm-generic/global_data.h |  4 ++++
>   2 files changed, 16 insertions(+)
> 
> diff --git a/common/cyclic.c b/common/cyclic.c
> index b37cd6d8ff0..714d6863d5b 100644
> --- a/common/cyclic.c
> +++ b/common/cyclic.c
> @@ -68,11 +68,17 @@ static void cyclic_run(void)
>   	struct cyclic_info *cyclic;
>   	struct hlist_node *tmp;
>   	u64 now, cpu_time;
> +	u64 next_call = UINT64_MAX;
>   
>   	/* Prevent recursion */
>   	if (gd->flags & GD_FLG_CYCLIC_RUNNING)
>   		return;
>   
> +	/* check if the next cyclic function's timestamp is reached */
> +	now = get_timer_us(0);
> +	if (time_after_eq64(gd->next_cyclic_call, now))
> +		return;
> +
>   	gd->flags |= GD_FLG_CYCLIC_RUNNING;
>   	hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) {
>   		/*
> @@ -102,7 +108,13 @@ static void cyclic_run(void)
>   				cyclic->already_warned = true;
>   			}
>   		}
> +		if (next_call > cyclic->next_call)
> +			next_call = cyclic->next_call;

Can you move this entry to the beginning of the cyclic list, so that the 
entry with the earliest deadline would be right at the beginning of the 
list ? That should squeeze some more improvement out of this I think.

>   	}
> +
> +	if (next_call != UINT64_MAX)

Can the next_call literally hit UINT64_MAX in that one unlikely case ?
You likely do need a separate flag, bool next_call_valid, to avoid that 
edge case.

> +		gd->next_cyclic_call = next_call;
> +
>   	gd->flags &= ~GD_FLG_CYCLIC_RUNNING;
>   }
Thank you !