mcexec: --disable-sched-yield: avoid kernel/user switch

executer/user/libsched_yield.c

@@ -0,0 +1,27 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <sys/time.h>
+#include <sched.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#undef sched_yield
+
+typedef int (*int_void_fn)(void);
+
+static int_void_fn orig_sched_yield = 0;
+
+int sched_yield(void)
+{
+#if 0
+	if (!orig_sched_yield) {
+		orig_sched_yield = (int_void_fn)dlsym(RTLD_NEXT, "sched_yield");
+	}
+
+	printf("sched_yield() called\n");
+#endif
+
+	return 0;
+}