If sched_try_shutdown() is not inlined into timer_dispatch_many() it
can have a significant impact on benchmarks. (Even though the
function isn't called in practice, the call causes gcc to organize the
function differently.)
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
On the AVR platform (and possibly others) the longjmp() call will
restore the interrupt state saved during the setjmp() call. So, the
setjmp() call must be invoked with interrupts disabled to ensure that
shutdown handling is run with interrupts disabled. This fixes
potential corruption of the shutdown processing on AVR.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Send a "startup" message after completing the mcu init functions.
This may help detect mcu reboots during debugging.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Track when tasks are pending and spin in irq_wait() when no tasks are
pending. This improves the mechanism for sleeping the processor -
it's simpler for the board specific code and it reduces the
possibility of the processor sleeping when tasks are busy.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Add function to indicate when tasks need to be run. This will allow
the scheduler code to know if there are any tasks that need to be
processed.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Don't rely on the generic scheduler code to always have a timer no
more than 1ms in the future. Instead, create an avr specific timer
that will be called every 0x8000 ticks. This simplifies the generic
code and it reduces the amount of code that needs to be run every
millisecond.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
If sched_add_timer() is called on a timer that would make it the new
head of the list, then add it and signal the board code that the timer
should be rescheduled.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
It's not necessary to keep a millisecond counter. Replace the two
users of sched_check_periodic() with explicit task wakeup flags.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Avoid using linker magic to define the init, task, and shutdown
functions. Instead, use the compile_time_request system. This
simplifies the build and produces more efficient code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Rename sched_timer_kick() to sched_timer_dispatch() and move its loop
into its callers in the board code. This eliminates the need to
export timer_try_set_next() from the board code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Explicilty load the timer waketime variable into local variables in
sched_timer_kick(). Change the optimization level from Os to O2.
This helps gcc to avoid unnecessary reloads from memory in the common
stepper_event() case.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Provide hand-coded assembler for timer_is_before() on AVR as that code
is used frequently in the time-critical timer dispatch loop and gcc
doesn't do a good job at compiling that comparison code. Remove the
no longer needed waketime+1 hack from reschedule_timer().
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Move sched_is_before() from sched.c to timer_is_before() in the board
specific timer code. This allows the board code to provide its own
definition.
Also, remove the sched_from_us() and sched_read_time() wrapper
functions and change the callers to directly invoke timer_from_us() /
timer_read_time().
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
If a shutdown occurs while the machine is already shutdown, then keep
the original shutdown reason code.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
It's tricky to reschedule the timer irq correctly (due to race
conditions with the irq) and in practice it's very rarely needed.
Handle the special cases in the generic sched.c code so that the board
code doesn't have to handle it.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Introduce a dummy sentinel timer object that is always the last item
on timer_list. This optimizes the timer_list walking code as it no
longer needs to check for NULL when traversing the list.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Tweak the AVR register pressure optimization in reschedule_timer() to
optimize it further. This improves the performance of AVR timers when
there are several pending timers.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Some architectures are faster passing regular integers than 8bit
integers. Use uint_fast8_t so that the architecture chooses the
appropriate type.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
The AVR wants a uint8_t return type for irq_save(), but other
architectures will generally prefer int. Allow the board to configure
the size of the flag by introducing an irqstatus_t typedef.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Kevin O'Connor