Fix-Point commented on PR #17345: URL: https://github.com/apache/nuttx/pull/17345#issuecomment-3560964929
> @Fix-Point See the message we got in the Discord: > > "Parthiban (Linumiz) — 10/16/25, 11:51 PM Morgen. Currently am analyzing to implement system timer for a new architecture. There are 3 timers available, > > ``` > timer > oneshot > arch timer > ``` > > I couldn't find the difference and when to use what. System timer for the tick / scheduler needs to be arch timer? Thanks." > > Please include an brief explanation about it in your Documentation introduction, it will help people that are starting to use NuttX to get some better understanding The current driver abstraction in NuttX's time subsystem can be broadly categorized into four layers: <img width="556" height="276" alt="image" src="https://github.com/user-attachments/assets/b0802f8b-f98a-4e31-845b-87a8f14c6e80"; /> **Hardware Timer Drivers**: Includes implementations of various hardware timer drivers. **Timer Driver Abstraction**: Such as `Oneshot` and `Timer`, which provide oneshot/periodical timer hardware abstraction. **OS Timer Interfaces**: `Arch_Timer(up_timer_*)` and `Arch_Alarm(up_alarm_*)`, offering relative timer (trigger an event with a certain delay) and absolute timer (trigger an event at a certain time) interfaces. OS Timer Abstraction: The `wdog` manages software timers and provides a unified timer API to upper layers. The timer driver abstraction is not mandatory. If the driver is simple enough (e.g., just providing a periodic ticks), the OS Timer interfaces `Arch_Timer` can be implemented directly, bypassing the timer driver abstraction layer. The purpose of the timer driver abstraction is to simplify driver implementation, improve performance, and enhance the reusability of driver code. Given NuttX's current state, for better performance and simplicity, I recommend that periodic tick timers directly implement the `up_timer_*` interfaces, and non-periodic timers implement the new count-based `oneshot` driver abstraction interface. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
