callgrind: initial notes

1 files changed, 36 insertions, 0 deletions

diff --git a/src/trace_profile/callgrind/cg_example.cc b/src/trace_profile/callgrind/cg_example.cc
new file mode 100644
index 0000000..d143790
--- /dev/null
+++ b/src/trace_profile/callgrind/cg_example.cc
@@ -0,0 +1,36 @@
+#include <cstdio>
+#include <thread>
+
+#include <valgrind/callgrind.h>
+
+struct cnt {
+  volatile int a;
+  volatile int b;
+};
+
+void inc_a(cnt &c) { c.a++; }
+void inc_b(cnt &c) { c.b++; }
+
+int main() {
+  cnt C{0, 0};
+
+  CALLGRIND_START_INSTRUMENTATION;
+
+  std::thread T1([&C]() {
+    for (int i = 0; i < 20000000; ++i) {
+      inc_a(C);
+    }
+  });
+  std::thread T2([&C]() {
+    for (int i = 0; i < 10000000; ++i) {
+      inc_b(C);
+    }
+  });
+  T1.join();
+  T2.join();
+
+  CALLGRIND_STOP_INSTRUMENTATION;
+
+  printf("%d %d\n", C.a, C.b);
+  return 0;
+}