This allows concurrent read access, which are much more common; reducing
potential lock contention and increasing concurrency.
Taking a lock is expensive, and the reader lock is now even more expensive.
An RCU synchronization scheme would reduce the overhead of the readers to
increasing/decreasing an atomic counter.
Thus this should only be an intermediate step until we move towards RCU.
Tested on SITL & Pixracer.
param_t is only used as an offset and we have <1000 params, so an uint16_t
is enough.
This saves roughly 1KB of RAM. We only do that on NuttX because normal
integers have better performance in general.
Previously on amd64, this was even 64bits because it was an uintptr_t.
This further speeds up param loading.
On Pixracer via USB, it's possible to send up to 11 at once before the TX
buffer gets full, so there is still enough free bandwidth left.
This speeds up parameter loading. Slow links like telemetry are unaffected,
since the mavlink loop runs only with ~100Hz.
Tested on various links, like:
- telemetry link
- pixracer WiFi
- pixracer USB
- SITL
The check if stick were touched was only working in one direction (per
axis) because fabsf was used incorrectly.
However, this check is still only a differential check triggered by
fast movement and does not trigger if someone slowly moves a stick to
the side. Also, the sensitivity depends on the rate of the commander
loop and/or the RC update loop. The correct solution would be a proper
filtering and trigger for movement.
This backend will keep all updated data in RAM and
persist the data between reboots using flash memory.
Using only flash memory would result in a slow backend that
would decrease the lifetime of the flash memory, using both
we can reduce the several cycles of erase & write into flash
and keep the performance of the backend almost as fast
as the RAM only backend.
Note: Do not use this backend on a sector from the same flash memory
bank as the memory bank that STM32 read instructions or it can block
the CPU from fetching instructions from flash during the erase and
write operations and cause your drone crash.
The initialization code is redundant and incomplete (only the first sensor
is done). I verified that all drivers already set this on startup.
For the mags, they all set their maximum supported update rate.
For the baro, the call can silently fail, as for example the MS5611 which
does not support 150Hz update. But it also sets the maximum in
initialization.
Tested on Pixhawk & pixracer.
In HIL mode we do not start the sensors anymore, so this is not needed.
Also it did not work (I did not try to find the reason, just noticed the
sensors kept publishing in HIL mode)
On SITL startup we got a datalink lost failsafe message whenever home
was initialized. The reason that in standalone SITL, there is usually no
datalink connected. However, on ground, we shouldn't really failsafe,
therefore it makes sense not to enter the state in the first place.
logger will always log this topic, and a 0 timestamp will look worse in
FlightPlot. This will show a period of 0 attitude instead before ekf
is initialized.
Beat Küng