[PATCH v2 07/14] cyclic: invoke uthread_schedule() from schedule()

[Stefan Roese]

Hi Jerome,

On 25.02.25 17:34, Jerome Forissier wrote:
> Make the schedule() call from the CYCLIC framework a uthread scheduling
> point too. This makes sense since schedule() is called from a lot of
> places where uthread_schedule() needs to be called.
> 
> Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>

Frankly, at first I was wondering a bit, if and why another framework
for "multitasking" is needed in U-Boot, additionally to the cyclic
framework that I introduced a few years ago. Which was greatly enhanced
by Rasmus over the time. But looking at your "uthread" implementation
it makes sense to add such a probably more intuitive interface as well.

In general I'm really happy seeing activity in this "multitaking" area
in U-Boot. As it brings a lot of new possibilities and, as you've also
shown in your patchset, may greatly help reducing boot time in the
USB example. :)

One question though:
Do you have some means in your uthread framework, measuring and
perhaps limiting the time spent in these uthreads? If and how is a
preemption of a uthread possible? So that it does not consume too
much time resulting in e.g. things like dropping input chars on
the prompt? Sorry, I did not thoroughly go through all your code
to get the internals from there. It would be great if you could
elaborate a bit on this.

For this patch:

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
>   common/cyclic.c           | 3 +++
>   include/u-boot/schedule.h | 3 +++
>   2 files changed, 6 insertions(+)
> 
> diff --git a/common/cyclic.c b/common/cyclic.c
> index fad071a39c6..b695f092f52 100644
> --- a/common/cyclic.c
> +++ b/common/cyclic.c
> @@ -16,6 +16,7 @@
>   #include <linux/list.h>
>   #include <asm/global_data.h>
>   #include <u-boot/schedule.h>
> +#include <uthread.h>
>   
>   DECLARE_GLOBAL_DATA_PTR;
>   
> @@ -100,6 +101,8 @@ void schedule(void)
>   	 */
>   	if (gd)
>   		cyclic_run();
> +
> +	uthread_schedule();
>   }
>   
>   int cyclic_unregister_all(void)
> diff --git a/include/u-boot/schedule.h b/include/u-boot/schedule.h
> index 4fd34c41229..4605971fdcb 100644
> --- a/include/u-boot/schedule.h
> +++ b/include/u-boot/schedule.h
> @@ -3,6 +3,8 @@
>   #ifndef _U_BOOT_SCHEDULE_H
>   #define _U_BOOT_SCHEDULE_H
>   
> +#include <uthread.h>
> +
>   #if CONFIG_IS_ENABLED(CYCLIC)
>   /**
>    * schedule() - Schedule all potentially waiting tasks
> @@ -17,6 +19,7 @@ void schedule(void);
>   
>   static inline void schedule(void)
>   {
> +	uthread_schedule();
>   }
>   
>   #endif

Viele Grüße,
Stefan Roese

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