[fiber] Stackful cooperative scheduling via Fibers

.github/workflows/linux.yml

@@ -197,7 +197,7 @@ jobs:
       - name: Compile AVR Unittests ATmega
         if: always()
         run: |
-          (cd test && make compile-mega-2560-pro)
+          (cd test && make compile-mega-2560-pro_A compile-mega-2560-pro_B)
       - name: Quick compile HAL for AVR Devices
         if: always()
         run: |

.github/workflows/macos.yml

@@ -53,18 +53,22 @@ jobs:
           git submodule update --init --jobs 8
 
       - name: Hosted Unittests
+        if: always()
         run: |
           (cd test && make run-hosted-darwin)
 
       - name: Hosted Examples
+        if: always()
         run: |
           (cd examples && ../tools/scripts/examples_compile.py linux)
 
       - name: Compile STM32 Examples
+        if: always()
         run: |
           (cd examples && ../tools/scripts/examples_compile.py nucleo_f031k6 nucleo_f103rb nucleo_f303re nucleo_f411re nucleo_f746zg)
           (cd examples && ../tools/scripts/examples_compile.py nucleo_g071rb nucleo_l031k6 nucleo_l152re nucleo_l476rg nucleo_g474re)
 
       - name: Compile AVR Examples
+        if: always()
         run: |
           (cd examples && ../tools/scripts/examples_compile.py avr)

.github/workflows/windows_hosted.yml

@@ -56,9 +56,10 @@ jobs:
       - name: Hosted Examples
         shell: bash
         run: |
-          (cd examples && python ../tools/scripts/examples_compile.py linux/assert linux/block_device linux/build_info linux/git linux/logger linux/printf)
+          (cd examples && python ../tools/scripts/examples_compile.py linux/assert linux/block_device linux/build_info linux/git linux/logger linux/printf linux/etl linux/fiber)
 
       - name: Hosted Unittests
+        if: always()
         shell: bash
         run: |
           (cd test && make run-hosted-windows)

examples/avr/fiber/main.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2020, Erik Henriksson
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+#include <modm/debug/logger.hpp>
+#include <modm/processing.hpp>
+
+using namespace Board;
+using namespace std::chrono_literals;
+
+constexpr uint32_t cycles = 100'000;
+volatile uint32_t f1counter = 0, f2counter = 0;
+uint32_t total_counter=0;
+
+void
+fiber_function1()
+{
+	MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+	while (++f1counter < cycles) { modm::fiber::yield(); total_counter++; }
+}
+
+void
+fiber_function2(uint32_t cyc)
+{
+	MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+	while (++f2counter < cyc) { modm::fiber::yield(); total_counter++; }
+}
+
+struct Test
+{
+	void
+	fiber_function3()
+	{
+		MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+		while (++f3counter < cycles) { modm::fiber::yield(); total_counter++; }
+	}
+
+	void
+	fiber_function4(uint32_t cyc)
+	{
+		MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+		while (++f4counter < cyc) { modm::fiber::yield(); total_counter++; }
+	}
+
+	volatile uint32_t f3counter{0};
+	volatile uint32_t f4counter{0};
+} test;
+
+modm::fiber::Stack<128> stack1;
+modm::fiber::Stack<128> stack2;
+modm::fiber::Stack<128> stack3;
+modm::fiber::Stack<128> stack4;
+modm::Fiber fiber1(stack1, fiber_function1);
+modm::Fiber fiber2(stack2, [](){ fiber_function2(cycles); });
+modm::Fiber fiber3(stack3, [](){ test.fiber_function3(); });
+modm::Fiber fiber4(stack4, [cyc=uint32_t(cycles)]() mutable { cyc++; test.fiber_function4(cyc); });
+
+// ATmega2560@16MHz: 239996 yields in 2492668us, 96280 yields per second, 10386ns per yield
+int
+main()
+{
+	Board::initialize();
+	Board::LedD13::setOutput();
+	MODM_LOG_INFO << "Starting fiber modm::yield benchmark..." << modm::endl;
+	MODM_LOG_INFO.flush();
+
+	const modm::PreciseTimestamp start = modm::PreciseClock::now();
+	modm::fiber::Scheduler::run();
+	const auto diff = (modm::PreciseClock::now() - start);
+
+	MODM_LOG_INFO << "Benchmark done!" << modm::endl;
+	MODM_LOG_INFO << "Executed " << total_counter << " yields in " << diff << modm::endl;
+	MODM_LOG_INFO << uint32_t((total_counter * 1'000'000ull) / std::chrono::microseconds(diff).count());
+	MODM_LOG_INFO << " yields per second, ";
+	MODM_LOG_INFO << uint32_t(std::chrono::nanoseconds(diff).count() / total_counter);
+	MODM_LOG_INFO << "ns per yield" << modm::endl;
+	MODM_LOG_INFO.flush();
+
+	while(1) ;
+	return 0;
+}

examples/avr/fiber/project.xml

@@ -0,0 +1,13 @@
+<library>
+  <extends>modm:mega-2560-pro</extends>
+  <!-- <extends>modm:arduino-nano</extends> -->
+  <options>
+    <option name="modm:build:build.path">../../../build/avr/fiber</option>
+    <option name="modm:__fibers">yes</option>
+  </options>
+  <modules>
+    <module>modm:build:scons</module>
+    <module>modm:processing:timer</module>
+    <module>modm:processing:fiber</module>
+  </modules>
+</library>

examples/generic/fiber/main.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2020, Erik Henriksson
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+#include <modm/debug/logger.hpp>
+#include <modm/processing.hpp>
+
+using namespace Board;
+using namespace std::chrono_literals;
+
+constexpr uint32_t cycles = 1'000'000;
+volatile uint32_t f1counter = 0, f2counter = 0;
+uint32_t total_counter=0;
+
+void
+fiber_function1()
+{
+	MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+	while (++f1counter < cycles) { modm::fiber::yield(); total_counter++; }
+}
+
+void
+fiber_function2(uint32_t cyc)
+{
+	MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+	while (++f2counter < cyc) { modm::fiber::yield(); total_counter++; }
+}
+
+struct Test
+{
+	void
+	fiber_function3()
+	{
+		MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+		while (++f3counter < cycles) { modm::fiber::yield(); total_counter++; }
+	}
+
+	void
+	fiber_function4(uint32_t cyc)
+	{
+		MODM_LOG_INFO << MODM_FILE_INFO << modm::endl;
+		while (++f4counter < cyc) { modm::fiber::yield(); total_counter++; }
+	}
+
+	volatile uint32_t f3counter{0};
+	volatile uint32_t f4counter{0};
+} test;
+
+modm_faststack modm::fiber::Stack<2048> stack1;
+modm_faststack modm::fiber::Stack<2048> stack2;
+modm_faststack modm::fiber::Stack<2048> stack3;
+modm_faststack modm::fiber::Stack<2048> stack4;
+modm_fastdata  modm::Fiber fiber1(stack1, fiber_function1);
+modm_fastdata  modm::Fiber fiber2(stack2, [](){ fiber_function2(cycles); });
+modm_fastdata  modm::Fiber fiber3(stack3, [](){ test.fiber_function3(); });
+modm_fastdata  modm::Fiber fiber4(stack4, [cyc=uint32_t(0)]() mutable { cyc++; test.fiber_function4(cyc); });
+
+// Blue pill (M3 72MHz): Executed 1000000 in 1098591us (910256.88 yields per second)
+// Feather M0 (M0+ 48MHz): Executed 1000000 in 1944692us (514220.25 yields per second)
+int
+main()
+{
+	Board::initialize();
+	MODM_LOG_INFO << "Starting fiber modm::yield benchmark..." << modm::endl;
+	MODM_LOG_INFO.flush();
+
+	const modm::PreciseTimestamp start = modm::PreciseClock::now();
+	modm::fiber::Scheduler::run();
+	const auto diff = (modm::PreciseClock::now() - start);
+
+	MODM_LOG_INFO << "Benchmark done!" << modm::endl;
+	MODM_LOG_INFO << "Executed " << total_counter << " yields in " << diff << modm::endl;
+	MODM_LOG_INFO << ((total_counter * 1'000'000ull) / std::chrono::microseconds(diff).count());
+	MODM_LOG_INFO << " yields per second, ";
+	MODM_LOG_INFO << (std::chrono::nanoseconds(diff).count() / total_counter);
+	MODM_LOG_INFO << "ns per yield" << modm::endl;
+	MODM_LOG_INFO.flush();
+
+	while(1) ;
+	return 0;
+}

examples/generic/fiber/project.xml

@@ -0,0 +1,13 @@
+<library>
+  <extends>modm:nucleo-f429zi</extends>
+  <!-- <extends>modm:nucleo-g071rb</extends> -->
+  <options>
+    <option name="modm:build:build.path">../../../build/generic/fiber</option>
+    <option name="modm:__fibers">yes</option>
+  </options>
+  <modules>
+    <module>modm:build:scons</module>
+    <module>modm:processing:timer</module>
+    <module>modm:processing:fiber</module>
+  </modules>
+</library>

examples/linux/fiber/main.cpp

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2021, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/debug.hpp>
+#include <modm/processing.hpp>
+
+void hello()
+{
+	for(int ii=0; ii<10; ii++)
+	{
+		MODM_LOG_INFO << "Hello ";
+		modm::fiber::yield();
+	}
+}
+
+struct Test
+{
+	void world(const char *arg)
+	{
+		for(int ii=0; ii<10; ii++)
+		{
+			MODM_LOG_INFO << arg << modm::endl;
+			modm::fiber::yield();
+		}
+	}
+} test;
+
+modm::fiber::Stack<1024> stack1;
+modm::fiber::Stack<1024> stack2;
+modm::Fiber fiber1(stack1, hello);
+
+int
+main(void)
+{
+	const char *arg = "World";
+	modm::Fiber fiber2(stack2, [=]() { test.world(arg); });
+
+	MODM_LOG_INFO << "Start" << modm::endl;
+	modm::fiber::Scheduler::run();
+	MODM_LOG_INFO << "End" << modm::endl;
+
+	return 0;
+}

examples/linux/fiber/project.xml

@@ -0,0 +1,14 @@
+<library>
+  <!-- CI: run -->
+  <options>
+    <option name="modm:target">hosted-linux</option>
+    <option name="modm:build:build.path">../../../build/linux/fiber</option>
+    <option name="modm:__fibers">yes</option>
+  </options>
+  <modules>
+    <module>modm:debug</module>
+    <module>modm:platform:core</module>
+    <module>modm:processing:fiber</module>
+    <module>modm:build:scons</module>
+  </modules>
+</library>

repo.lb

@@ -274,6 +274,10 @@ def init(repo):
                      description=descr_target,
                      enumeration=devices))
 
+    # Invisible option guarding the Fiber API until it is ready
+    repo.add_option(BooleanOption(name="__fibers", default=False,
+                                  description="Enable unstable fiber API."))
+
 def prepare(repo, options):
     repo.add_modules_recursive("ext", modulefile="*.lb")
     repo.add_modules_recursive("src", modulefile="*.lb")

src/modm/architecture/utils.hpp

@@ -72,6 +72,9 @@
 	/// Marks a declaration as deprecated and displays a message.
 	#define modm_deprecated(msg)
 
+	/// Tells the compiler to not generate prologue/epilogue code for this function.
+	#define modm_naked
+
 	/// Places a function in the fastest executable memory:
 	/// instruction cache, core coupled memory or SRAM as fallback.
 	#define modm_fastcode
@@ -81,6 +84,11 @@
 	/// @note This memory location may not be DMA-able!
 	#define modm_fastdata
 
+	/// Places an array into the fastest accessible memory *with* DMA access:
+	/// data cache, core coupled memory or SRAM as fallback.
+	/// @note This memory location is DMA-able, but uninitialized!
+	#define modm_faststack
+
 	/// This branch is more likely to execute.
 	#define modm_likely(x) (x)
 
@@ -129,6 +137,7 @@
 	#define modm_fallthrough		__attribute__((fallthrough))
 	#define modm_noreturn			__attribute__((noreturn))
 	#define modm_warn_unused_result	__attribute__((warn_unused_result))
+	#define modm_naked				__attribute__((naked))
 
 	#ifdef MODM_COMPILER_MINGW
 	 	// FIXME: Windows Object Format PE does not support weak symbols
@@ -144,10 +153,12 @@
 	#	define modm_fastcode
 	#	define modm_ramcode
 	#	define modm_fastdata
+	#	define modm_faststack
 	#else
 	#	define modm_fastcode		modm_section(".fastcode")
 	#	define modm_ramcode			modm_fastcode
 	#	define modm_fastdata		modm_section(".fastdata")
+	#	define modm_faststack		modm_section(".faststack")
 	#endif
 
 	#ifdef __cplusplus