1 files changed, 51 insertions, 0 deletions
diff --git a/test/instr_demo.c b/test/instr_demo.c
new file mode 100644
index 0000000..7983b82
--- /dev/null
+++ b/test/instr_demo.c
@@ -0,0 +1,51 @@
+// a fully instrumented demo: built with -finstrument-functions so EVERY function
+// here is traced automatically, no hand-picking. kept in plain C with only
+// printf and nanosleep so the trace is exactly these functions
+#include <stdio.h>
+#include <time.h>
+
+static void nap(long ms)
+{
+    struct timespec ts = { ms / 1000, (ms % 1000) * 1000000L };
+    nanosleep(&ts, NULL);
+}
+
+static long leaf(int n)
+{
+    long total = 0;
+    for (int i = 0; i < n * 40000; ++i)
+        total += i % 7;
+
+    return total;
+}
+
+static long inner(int round)
+{
+    long total = 0;
+    for (int i = 1; i <= 3; ++i)
+        total += leaf(round % 4 + i);
+
+    return total;
+}
+
+static long outer(int round)
+{
+    const long a = inner(round);
+    nap(20);
+    const long b = inner(round + 1);
+    return a + b;
+}
+
+int main(void)
+{
+    for (int round = 0; round < 15; ++round)
+    {
+        const long result = outer(round);
+        printf("round %d -> %ld\n", round, result);
+        fflush(stdout);
+        nap(120);
+    }
+
+    puts("done");
+    return 0;
+}