This commit added the guard timer for hrtimer.
The guard timer uses a small memory footprint, offering two main advantages:
- Reduced branches checking for an empty hrtimer queue, simplifying code implementation and improving the performance.
- Additional health monitoring allows the system to enter a safe state in case of time acquisition errors, and supports custom error handling callback functions.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
If there are no timers in the hrtimer queue, we should cancel the timers to avoid unnecessary timer interruptions. Since we currently do not have a timer cancellation interface, we can achieve cancellation by setting the timer to its maximum value.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
When a hrtimer is removed and then re-enqueued, if the removed hrtimer is the head node and the re-enqueued node is not the head node, the hardware timer still needs to be reset. This patch fixes this issue and simplifies the enqueuing.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
This commit renamed the hrtimer_is_armed to hrtimer_is_pending, which is
more accurate in the semamtic, and simplify it.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
On 32-bit platform with 64-bit pointer, read/write to the
`g_hrtimer_running` is not atomic, we should protect it with the
seqcount to ensure the value we read is correct.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
Since the hrtimer->expired is not monotonic, it can not be used as the
version. This commit added the ownership encoding to ensure the
invariant that the cancelled the timer can not modify the hrtimer again.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
This commit fixed the functional correctness issues in tick mode
and non-tickless alarm mode.
- In tick mode, we do not need reprogram the timer.
- In non-tickless alarm mode, the up_timer_start receive the relative time as the parameter.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
Several code comments in the hrtimer subsystem have become outdated
following recent implementation changes. This patch updates them to
accurately describe the current code behavior and algorithms.
Signed-off-by: Chengdong Wang <wangcd91@gmail.com>
Separate SMP-specific logic from the hrtimer core to improve
performance and maintainability.
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
The expired field can not be used to indicate the cancelled state. Because
the `UINT64_MAX` is valid expired time. A periodic hrtimer started with
the hrtimer_start_absolute(hrtimer, period_func, UINT64_MAX) can
not be cancelled via `hrtimer_cancel`.
Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
Allow running/armed hrtimer to be restarted to
fix hrtimer bug: #17567
Co-authored-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
Add a safe synchronous hrtimer cancel API, hrtimer_cancel_sync().
If the timer callback is currently executing, this function waits
until the callback has completed and the timer state transitions
to HRTIMER_STATE_INACTIVE.
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
NuttX provides the wdog module to implement timers for the scheduler.
While it is lightweight and efficient, wdog only supports tick-level timers,
typically in milliseconds. Although the tick duration can be configured,
setting it to microsecond or nanosecond resolution is not practical.
Doing so may cause an interrupt storm, where the CPU is constantly
occupied handling tick interrupts.
To address this limitation, a new hrtimer module is introduced.
It coexists with the wdog module, providing both tick-level timers
for wdog and high-resolution timers (nanosecond-level) directly to users.
Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>
