Bugfix: Dedicated event signalling for each thread

[aentinger]

Objective

Previous implementation required call to rtos::ThisThread::yield() in every thread in order to prevent what I thought was a result of resource starvation (only messages from one thread were printed). However, it was the result of using a single condition variable instead of one condition variable per thread. Now there's one dedicated signalling flag per thread by using EventFlags.

Output of Threadsafe_Serial_Writer

Note: All threads are executed in chronological order, this is preemptive round-robin-scheduling seen in action.

[1339741] Thread #1: Lorem ipsum ...
[1339743] Thread #2: Lorem ipsum ...
[1339744] Thread #3: Lorem ipsum ...
[1339746] Thread #0: Lorem ipsum ...
[1339748] Thread #1: Lorem ipsum ...
[1339750] Thread #2: Lorem ipsum ...
[1339751] Thread #3: Lorem ipsum ...
[1339753] Thread #0: Lorem ipsum ...
[1339755] Thread #1: Lorem ipsum ...
[1339757] Thread #2: Lorem ipsum ...
[1339758] Thread #3: Lorem ipsum ...
[1339760] Thread #0: Lorem ipsum ...
[1339762] Thread #1: Lorem ipsum ...

[github-actions]

Memory usage change @ 29c42ee

Board	flash	%	RAM for global variables	%
arduino:mbed_nano:nano33ble	🔺 +4928 - +5440	+0.5 - +0.55	🔺 +8 - +16	0.0 - +0.01
arduino:mbed_nano:nanorp2040connect	0 - 0	0.0 - 0.0	🔺 +12 - +12	0.0 - 0.0
arduino:mbed_portenta:envie_m4	🔺 +3256 - +3832	+0.31 - +0.37	🔺 +8 - +16	0.0 - +0.01
arduino:mbed_portenta:envie_m7	🔺 +3320 - +3832	+0.42 - +0.49	🔺 +8 - +16	0.0 - 0.0

Click for full report table

Board	examples/Threading/Demo_Shared_Counter flash	%	examples/Threading/Demo_Shared_Counter RAM for global variables	%	examples/Threading/Demo_Source_Sink_Counter flash	%	examples/Threading/Demo_Source_Sink_Counter RAM for global variables	%	examples/Threading/Demo_Source_Sink_LED flash	%	examples/Threading/Demo_Source_Sink_LED RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_SPI flash	%	examples/Threadsafe_IO/Threadsafe_SPI RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_SPI_BusIO flash	%	examples/Threadsafe_IO/Threadsafe_SPI_BusIO RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Serial_GlobalPrefixSuffix flash	%	examples/Threadsafe_IO/Threadsafe_Serial_GlobalPrefixSuffix RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Serial_ProtocolWrapping flash	%	examples/Threadsafe_IO/Threadsafe_Serial_ProtocolWrapping RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Serial_Reader flash	%	examples/Threadsafe_IO/Threadsafe_Serial_Reader RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Serial_Writer flash	%	examples/Threadsafe_IO/Threadsafe_Serial_Writer RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Wire flash	%	examples/Threadsafe_IO/Threadsafe_Wire RAM for global variables	%	examples/Threadsafe_IO/Threadsafe_Wire_BusIO flash	%	examples/Threadsafe_IO/Threadsafe_Wire_BusIO RAM for global variables	%
arduino:mbed_nano:nano33ble	4928	0.5	8	0.0	5440	0.55	8	0.0	5376	0.55	16	0.01	5440	0.55	16	0.01	5440	0.55	16	0.01	5056	0.51	16	0.01	5272	0.54	16	0.01	5048	0.51	16	0.01	5048	0.51	16	0.01	5376	0.55	16	0.01	5376	0.55	16	0.01
arduino:mbed_nano:nanorp2040connect	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0	0	0.0	12	0.0
arduino:mbed_portenta:envie_m4	3256	0.31	16	0.01	3768	0.36	16	0.01	3768	0.36	8	0.0	3768	0.36	8	0.0	3768	0.36	8	0.0	3376	0.32	8	0.0	3528	0.34	8	0.0	3384	0.32	8	0.0	3384	0.32	8	0.0	3768	0.36	8	0.0	3832	0.37	8	0.0
arduino:mbed_portenta:envie_m7	3320	0.42	8	0.0	3832	0.49	8	0.0	3768	0.48	16	0.0	3768	0.48	16	0.0	3768	0.48	16	0.0	3440	0.44	16	0.0	3592	0.46	16	0.0	3448	0.44	16	0.0	3448	0.44	16	0.0	3832	0.49	16	0.0	3768	0.48	16	0.0

Click for full report CSV

Board,examples/Threading/Demo_Shared_Counter<br>flash,%,examples/Threading/Demo_Shared_Counter<br>RAM for global variables,%,examples/Threading/Demo_Source_Sink_Counter<br>flash,%,examples/Threading/Demo_Source_Sink_Counter<br>RAM for global variables,%,examples/Threading/Demo_Source_Sink_LED<br>flash,%,examples/Threading/Demo_Source_Sink_LED<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_SPI<br>flash,%,examples/Threadsafe_IO/Threadsafe_SPI<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_SPI_BusIO<br>flash,%,examples/Threadsafe_IO/Threadsafe_SPI_BusIO<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Serial_GlobalPrefixSuffix<br>flash,%,examples/Threadsafe_IO/Threadsafe_Serial_GlobalPrefixSuffix<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Serial_ProtocolWrapping<br>flash,%,examples/Threadsafe_IO/Threadsafe_Serial_ProtocolWrapping<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Serial_Reader<br>flash,%,examples/Threadsafe_IO/Threadsafe_Serial_Reader<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Serial_Writer<br>flash,%,examples/Threadsafe_IO/Threadsafe_Serial_Writer<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Wire<br>flash,%,examples/Threadsafe_IO/Threadsafe_Wire<br>RAM for global variables,%,examples/Threadsafe_IO/Threadsafe_Wire_BusIO<br>flash,%,examples/Threadsafe_IO/Threadsafe_Wire_BusIO<br>RAM for global variables,%
arduino:mbed_nano:nano33ble,4928,0.5,8,0.0,5440,0.55,8,0.0,5376,0.55,16,0.01,5440,0.55,16,0.01,5440,0.55,16,0.01,5056,0.51,16,0.01,5272,0.54,16,0.01,5048,0.51,16,0.01,5048,0.51,16,0.01,5376,0.55,16,0.01,5376,0.55,16,0.01
arduino:mbed_nano:nanorp2040connect,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0,0,0.0,12,0.0
arduino:mbed_portenta:envie_m4,3256,0.31,16,0.01,3768,0.36,16,0.01,3768,0.36,8,0.0,3768,0.36,8,0.0,3768,0.36,8,0.0,3376,0.32,8,0.0,3528,0.34,8,0.0,3384,0.32,8,0.0,3384,0.32,8,0.0,3768,0.36,8,0.0,3832,0.37,8,0.0
arduino:mbed_portenta:envie_m7,3320,0.42,8,0.0,3832,0.49,8,0.0,3768,0.48,16,0.0,3768,0.48,16,0.0,3768,0.48,16,0.0,3440,0.44,16,0.0,3592,0.46,16,0.0,3448,0.44,16,0.0,3448,0.44,16,0.0,3832,0.49,16,0.0,3768,0.48,16,0.0