1 files changed, 47 insertions, 0 deletions
diff --git a/test/sample_demo.cpp b/test/sample_demo.cpp
new file mode 100644
index 0000000..a3b1fa8
--- /dev/null
+++ b/test/sample_demo.cpp
@@ -0,0 +1,47 @@
+// a plain, un-instrumented target for the sampling profiler: NOTHING added to the
+// build, no flags, no linked runtime. functions do enough work (tens of ms) that
+// the sampler catches them. compile normally:  clang++ -g sample_demo.cpp -o sample_demo
+#include <cstdio>
+
+// a spin of roughly the requested milliseconds of busywork
+static volatile long sink = 0;
+static void burn(int ms)
+{
+    // ~2 million iterations per ms is a rough guess; exact timing does not matter
+    for (long i = 0; i < ms * 800000L; ++i)
+        sink += i % 7;
+}
+
+static void deep(int round)
+{
+    burn(25 + round % 3 * 15);
+}
+
+static void phase_b(int round)
+{
+    burn(20);
+    deep(round);
+}
+
+static void phase_a(int round)
+{
+    burn(40);
+}
+
+int main()
+{
+    for (int round = 0; round < 400; ++round)
+    {
+        phase_a(round);
+        phase_b(round);
+
+        if (round % 10 == 0)
+        {
+            printf("round %d\n", round);
+            fflush(stdout);
+        }
+    }
+
+    puts("done");
+    return 0;
+}