New SkMutex benchmark - used when we suspected mutex performance issues;
committed not because they're a bottleneck now but because we might do
something with them in the future & it's quite lightweight.



git-svn-id: http://skia.googlecode.com/svn/trunk@2675 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/MutexBench.cpp b/bench/MutexBench.cpp
new file mode 100644
index 0000000..d9b427b
--- /dev/null
+++ b/bench/MutexBench.cpp
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkBenchmark.h"
+#include "SkThread.h"
+
+class MutexBench : public SkBenchmark {
+    enum {
+        N = SkBENCHLOOP(80),
+        M = SkBENCHLOOP(200)
+    };
+public:
+    MutexBench(void* param) : INHERITED(param) {
+
+    }
+protected:
+    virtual const char* onGetName() {
+        return "mutex";
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        for (int i = 0; i < N; i++) {
+            SkMutex mu;
+            for (int j = 0; j < M; j++) {
+                mu.acquire();
+                mu.release();
+            }
+        }
+    }
+
+private:
+    typedef SkBenchmark INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkBenchmark* Fact(void* p) { return new MutexBench(p); }
+
+static BenchRegistry gReg01(Fact);
+
diff --git a/gyp/bench.gypi b/gyp/bench.gypi
index 6ac64d1..f0cdfe1 100644
--- a/gyp/bench.gypi
+++ b/gyp/bench.gypi
@@ -26,6 +26,7 @@
     '../bench/GradientBench.cpp',
     '../bench/MathBench.cpp',
     '../bench/MatrixBench.cpp',
+    '../bench/MutexBench.cpp',
     '../bench/PathBench.cpp',
     '../bench/RectBench.cpp',
     '../bench/RepeatTileBench.cpp',