tests: add a test app for schedstatistics

tests/ps_schedstatistics/Makefile

+APPLICATION = ps_schedstatistics
+include ../Makefile.tests_common
+
+BOARD_INSUFFICIENT_MEMORY := chronos msb-430 msb-430h nucleo-f030 nucleo-l053 \
+                             nucleo32-f031 nucleo32-f042 nucleo32-l031 \
+                             stm32f0discovery telosb weio wsn430-v1_3b \
+                             wsn430-v1_4 z1
+
+CFLAGS += -DDEVELHELP
+USEMODULE += shell
+USEMODULE += shell_commands
+USEMODULE += ps
+USEMODULE += schedstatistics
+USEMODULE += printf_float
+
+include $(RIOTBASE)/Makefile.include

tests/ps_schedstatistics/main.c

+/*
+ * Copyright (C) 2017 OTA keys S.A.
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief ps schedstatistics test app
+ *
+ * @author Vincent Dupont <vincent@otakeys.com>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+
+#include <shell.h>
+#include <thread.h>
+#include <xtimer.h>
+
+#define NB_THREADS 5
+
+static char stacks[NB_THREADS][THREAD_STACKSIZE_DEFAULT];
+static kernel_pid_t pids[NB_THREADS];
+
+static void *_thread_fn(void *arg)
+{
+    int next = (int)arg < NB_THREADS - 1 ? (int)arg + 1 : 0;
+    msg_t msg;
+
+    printf("Creating thread #%d, next=%d\n", (int)arg, next);
+
+    while (1) {
+        msg_receive(&msg);
+        xtimer_usleep(XTIMER_BACKOFF - 1);
+        xtimer_usleep(2 * XTIMER_BACKOFF);
+        msg_send(&msg, pids[next]);
+    }
+
+    return NULL;
+}
+
+int main(void)
+{
+    for (int i = 0; i < NB_THREADS; i++) {
+        pids[i] = thread_create(stacks[i], sizeof(stacks[i]),
+                                THREAD_PRIORITY_MAIN + 1,
+                                THREAD_CREATE_STACKTEST,
+                                _thread_fn, (void *)i, "thread");
+    }
+
+
+    msg_t msg;
+    msg_send(&msg, pids[0]);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+}