speed-up SkMatrix::preScale by 3x, by special-casing it instead of just calling

concat. Inspired by the profile of the fishtank site



git-svn-id: http://skia.googlecode.com/svn/trunk@1462 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 90 insertions, 0 deletions

diff --git a/bench/MatrixBench.cpp b/bench/MatrixBench.cpp
new file mode 100644
index 0000000000..1c99ab433e
--- /dev/null
+++ b/bench/MatrixBench.cpp
@@ -0,0 +1,90 @@
+#include "SkBenchmark.h"
+#include "SkMatrix.h"
+#include "SkString.h"
+
+class MatrixBench : public SkBenchmark {
+    SkString    fName;
+    enum { N = 100000 };
+public:
+    MatrixBench(void* param, const char name[]) : INHERITED(param) {
+        fName.printf("matrix_%s", name);
+    }
+
+    virtual void performTest() = 0;
+
+protected:
+    virtual const char* onGetName() {
+        return fName.c_str();
+    }
+
+    virtual void onDraw(SkCanvas* canvas) {
+        for (int i = 0; i < N; i++) {
+            this->performTest();
+        }
+    }
+
+private:
+    typedef SkBenchmark INHERITED;
+};
+
+// we want to stop the compiler from eliminating code that it thinks is a no-op
+// so we have a non-static global we increment, hoping that will convince the
+// compiler to execute everything
+int gMatrixBench_NonStaticGlobal;
+
+#define always_do(pred)                     \
+    do {                                    \
+        if (pred) {                         \
+            ++gMatrixBench_NonStaticGlobal; \
+        }                                   \
+    } while (0)
+
+class EqualsMatrixBench : public MatrixBench {
+public:
+    EqualsMatrixBench(void* param) : INHERITED(param, "equals") {}
+protected:
+    virtual void performTest() {
+        SkMatrix m0, m1, m2;
+        
+        m0.reset();
+        m1.reset();
+        m2.reset();
+        always_do(m0 == m1);
+        always_do(m1 == m2);
+        always_do(m2 == m0);
+        always_do(m0.getType());
+        always_do(m1.getType());
+        always_do(m2.getType());
+    }
+private:
+    typedef MatrixBench INHERITED;
+};
+
+class ScaleMatrixBench : public MatrixBench {
+public:
+    ScaleMatrixBench(void* param) : INHERITED(param, "scale") {
+        
+        fM0.reset();
+        fM1.setScale(fSX, fSY);
+        fM2.setTranslate(fSX, fSY);
+        fSX = fSY = SkFloatToScalar(1.5f);
+    }
+protected:
+    virtual void performTest() {
+        SkMatrix m;
+        m = fM0; m.preScale(fSX, fSY);
+        m = fM1; m.preScale(fSX, fSY);
+        m = fM2; m.preScale(fSX, fSY);
+    }
+private:
+    SkMatrix fM0, fM1, fM2;
+    SkScalar fSX, fSY;
+    typedef MatrixBench INHERITED;
+};
+
+static SkBenchmark* M0(void* p) { return new EqualsMatrixBench(p); }
+static SkBenchmark* M1(void* p) { return new ScaleMatrixBench(p); }
+
+static BenchRegistry gReg0(M0);
+static BenchRegistry gReg1(M1);
+