sys/event: manage event thread size via build system

makefiles/app_dirs.blacklist

@@ -20,4 +20,5 @@ tests/pkg/tflite-micro/external_modules/
 tests/pkg/utensor/external_modules/
 tests/pkg/wolfcrypt-ed25519-verify/
 tests/sys/suit_manifest/native_flashpage/
+tests/sys/event_thread_shared/external_modules/
 tests/unittests/

makefiles/utils/strings.mk

@@ -46,3 +46,8 @@ _is_equal = $(if $(and $(findstring $(1),$(2)),$(findstring $(2),$(1))),1,)
 version_is_greater_or_equal = $(or \
     $(call _is_greater,$(call _padded_version,$1),$(call _padded_version,$2)),\
     $(call _is_equal,$(call _padded_version,$1),$(call _padded_version,$2)))
+
+# Get the maximum number of the natural numbers given as $1
+#   $1: A list of natural numbers separated by white space
+#   Return: The value of the highest natural number in $1
+max_number = $(shell echo $1 | awk 'BEGIN{max=0} {for(i=1;i<=NF;i++){x=$$i; if (x > max){max = x}}} END{print max}')

makefiles/utils/test-strings.mk

@@ -35,3 +35,11 @@ test-version_is_greater_or_equal:
 	$(Q)test 1 = "$(call version_is_greater_or_equal,$(TEST_VERSION_4),$(TEST_VERSION_3))" || { echo ERROR: "$(TEST_VERSION_3)" \< "$(TEST_VERSION_4)"; exit 1; }
 	$(Q)test "" = "$(call version_is_greater_or_equal,$(TEST_VERSION_3),$(TEST_VERSION_4))" || { echo ERROR: Test should fail, "$(TEST_VERSION_4)" is not \< "$(TEST_VERSION_3)"; exit 1; }
 	$(Q)test "" = "$(call version_is_greater_or_equal,$(TEST_VERSION_1),$(TEST_VERSION_4))" || { echo ERROR: Test should fail, "$(TEST_VERSION_1)" is not \< "$(TEST_VERSION_4)"; exit 1; }
+
+test-max_number:
+	$(Q)test "8" = "$(call max_number, 7 4 8 0 1 3)"
+	$(Q)test "42" = "$(call max_number, 42 4 8 0 1 3)"
+	$(Q)test "1337" = "$(call max_number, 42 4 8 0 1 1337)"
+	$(Q)test "0" = "$(call max_number, 0 0 0 0 0)"
+	$(Q)test "13" = "$(call max_number, 13)"
+	$(Q)test "0" = "$(call max_number,)"

sys/Makefile.include

@@ -212,3 +212,7 @@ endif
 ifneq (,$(filter unicoap,$(USEMODULE)))
   include $(RIOTBASE)/sys/net/application_layer/unicoap/Makefile.include
 endif
+
+ifneq (,$(filter event,$(USEMODULE)))
+  include $(RIOTBASE)/sys/event/Makefile.include
+endif

sys/event/Makefile.include

@@ -0,0 +1,35 @@
+include $(RIOTMAKE)/utils/strings.mk
+
+# This applies to all thread stacks
+ifneq (, $(EVENT_THREAD_STACKSIZE_MIN))
+  EVENT_THREAD_STACKSIZE_MIN := $(call max_number,$(EVENT_THREAD_STACKSIZE_MIN))
+endif
+
+ifeq (,$(filter event_thread_highest, $(USEMODULE)))
+  # No highest priority event thread, so the highest prio queue is handled by
+  # the same thread handling the medium priority queue. So we "trickle down"
+  # the requirements here
+  EVENT_THREAD_MEDIUM_STACKSIZE_MIN += $(EVENT_THREAD_HIGHEST_STACKSIZE_MIN)
+else
+  ifneq (, $(EVENT_THREAD_HIGHEST_STACKSIZE_MIN))
+    EVENT_THREAD_HIGHEST_STACKSIZE_MIN := $(call max_number,$(EVENT_THREAD_HIGHEST_STACKSIZE_MIN) $(EVENT_THREAD_STACKSIZE_MIN))
+    CFLAGS += -DEVENT_THREAD_HIGHEST_STACKSIZE=$(EVENT_THREAD_HIGHEST_STACKSIZE_MIN)
+  endif
+endif
+
+ifeq (,$(filter event_thread_medium, $(USEMODULE)))
+  # No medium priority event thread, so the medium prio queue is handled by
+  # the same thread handling the lowest priority queue. So we "trickle down"
+  # the requirements here
+  EVENT_THREAD_LOWEST_STACKSIZE_MIN += $(EVENT_THREAD_MEDIUM_STACKSIZE_MIN)
+else
+  ifneq (, $(EVENT_THREAD_MEDIUM_STACKSIZE_MIN))
+    EVENT_THREAD_MEDIUM_STACKSIZE_MIN := $(call max_number,$(EVENT_THREAD_MEDIUM_STACKSIZE_MIN) $(EVENT_THREAD_STACKSIZE_MIN))
+    CFLAGS += -DEVENT_THREAD_MEDIUM_STACKSIZE=$(EVENT_THREAD_MEDIUM_STACKSIZE_MIN)
+  endif
+endif
+
+ifneq (, $(EVENT_THREAD_LOWEST_STACKSIZE_MIN))
+  EVENT_THREAD_LOWEST_STACKSIZE_MIN := $(call max_number,$(EVENT_THREAD_LOWEST_STACKSIZE_MIN) $(EVENT_THREAD_STACKSIZE_MIN))
+  CFLAGS += -DEVENT_THREAD_LOWEST_STACKSIZE=$(EVENT_THREAD_LOWEST_STACKSIZE_MIN)
+endif

sys/include/event/thread.h

@@ -44,6 +44,32 @@
  * event queue gets its own thread. So higher priority events will always
  * preempt events of lower priority in this case.
  *
+ * Managing Stack Size Requirements
+ * --------------------------------
+ *
+ * A module using the medium priority event queue might require a certain
+ * minimum stack size, say 1024, to operate correctly. Instead of just adding
+ * `CFLAGS += -DDEVENT_THREAD_MEDIUM_STACKSIZE=1024`, it can instead add the
+ * following to its `Makefile.dep`:
+ *
+ * ```Makefile
+ * EVENT_THREAD_MEDIUM_STACKSIZE_MIN += 1024
+ * ```
+ *
+ * In the `Makefile.include` of `sys/event` the highest value of the minimum
+ * requirements declared by any module will be picked and added to the
+ * `CFLAGS`.
+ *
+ * @note    `EVENT_THREAD_MEDIUM_STACKSIZE_MIN` and
+ *          `EVENT_THREAD_HIGHEST_STACKSIZE_MIN` always apply to the thread
+ *          managing the medium priority queue.
+ * @details  E.g. without the module `event_thread_medium` the lowest priority
+ *          and medium priority queues are both handled by the lowest priority
+ *          even thread. In that case, `EVENT_THREAD_MEDIUM_STACKSIZE_MIN` would
+ *          ensure a minimum thread statck size on the lowest priority even
+ *          thread. With `event_thread_medium` in use, it would instead apply
+ *          to the stack of the dedicated medium event queue thread.
+ *
  * @{
  *
  * @file

tests/build_system/utils/Makefile

@@ -24,6 +24,7 @@ COMPILE_TESTS += test-uppercase
 COMPILE_TESTS += test-uppercase_and_underscore
 COMPILE_TESTS += test-version_is_greater
 COMPILE_TESTS += test-version_is_greater_or_equal
+COMPILE_TESTS += test-max_number
 
 # Tests will be run both in the host machine and in `docker`
 all: build-system-utils-tests
@@ -59,3 +60,6 @@ test-version_is_greater:
 
 test-version_is_greater_or_equal:
 	$(Q)$(call command_should_succeed,"$(MAKE)" -C $(MAKEFILES_UTILS) -f test-strings.mk test-version_is_greater_or_equal)
+
+test-max_number:
+	$(Q)$(call command_should_succeed,"$(MAKE)" -C $(MAKEFILES_UTILS) -f test-strings.mk test-max_number)

tests/sys/event_thread_shared/Makefile

@@ -2,4 +2,12 @@ include ../Makefile.sys_common
 
 USEMODULE += event_thread
 
+# Test that selecting event thread size works from the modules `Makefile.dep`
+# work as expected by including a bunch of empty test module
+EXTERNAL_MODULE_DIRS += external_modules
+USEMODULE += test_module_a
+USEMODULE += test_module_b
+USEMODULE += test_module_c
+USEMODULE += test_module_d
+
 include $(RIOTBASE)/Makefile.include

tests/sys/event_thread_shared/external_modules/test_module_a/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

tests/sys/event_thread_shared/external_modules/test_module_a/Makefile.dep

@@ -0,0 +1 @@
+EVENT_THREAD_HIGHEST_STACKSIZE_MIN += 3

tests/sys/event_thread_shared/external_modules/test_module_b/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

tests/sys/event_thread_shared/external_modules/test_module_b/Makefile.dep

@@ -0,0 +1 @@
+EVENT_THREAD_HIGHEST_STACKSIZE_MIN += 300

tests/sys/event_thread_shared/external_modules/test_module_c/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

tests/sys/event_thread_shared/external_modules/test_module_c/Makefile.dep

@@ -0,0 +1 @@
+EVENT_THREAD_HIGHEST_STACKSIZE_MIN += 567

tests/sys/event_thread_shared/external_modules/test_module_d/Makefile

@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base

tests/sys/event_thread_shared/external_modules/test_module_d/Makefile.dep

@@ -0,0 +1 @@
+EVENT_THREAD_HIGHEST_STACKSIZE_MIN += 256

tests/sys/event_thread_shared/main.c

@@ -17,11 +17,17 @@
  * @}
  */
 
+#include <assert.h>
 #include <stdio.h>
 
 #include "thread.h"
 #include "event/thread.h"
 
+static_assert(EVENT_THREAD_LOWEST_STACKSIZE == 567,
+              "Selecting highest of the minimum stack size requirements "
+              "declared via `EVENT_THREAD_HIGHEST_STACKSIZE_MIN += <num>` "
+              "must work correctly");
+
 static void _handler_high(event_t *event) {
     (void)event;
     puts("high");