New scalar benchmark suite, comparing SkScalarAs2sCompliment vs native float operations
http://http://codereview.appspot.com/4532116/
git-svn-id: http://skia.googlecode.com/svn/trunk@1511 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/ScalarBench.cpp b/bench/ScalarBench.cpp
new file mode 100644
index 0000000..639d10d
--- /dev/null
+++ b/bench/ScalarBench.cpp
@@ -0,0 +1,96 @@
+#include "SkBenchmark.h"
+#include "SkRandom.h"
+#include "SkString.h"
+
+class ScalarBench : public SkBenchmark {
+ SkString fName;
+ enum { N = 100000 };
+public:
+ ScalarBench(void* param, const char name[]) : INHERITED(param) {
+ fName.printf("scalar_%s", name);
+ }
+
+ virtual void performTest() = 0;
+
+protected:
+ virtual int mulLoopCount() const { return 1; }
+
+ virtual const char* onGetName() {
+ return fName.c_str();
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ int n = N * this->mulLoopCount();
+ 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 gScalarBench_NonStaticGlobal;
+
+#define always_do(pred) \
+ do { \
+ if (pred) { \
+ ++gScalarBench_NonStaticGlobal; \
+ } \
+ } while (0)
+
+// having unknown values in our arrays can throw off the timing a lot, perhaps
+// handling NaN values is a lot slower. Anyway, this guy is just meant to put
+// reasonable values in our arrays.
+template <typename T> void init9(T array[9]) {
+ SkRandom rand;
+ for (int i = 0; i < 9; i++) {
+ array[i] = rand.nextSScalar1();
+ }
+}
+
+class FloatComparisonBench : public ScalarBench {
+public:
+ FloatComparisonBench(void* param) : INHERITED(param, "compare_float") {
+ init9(fArray);
+ }
+protected:
+ virtual int mulLoopCount() const { return 4; }
+ virtual void performTest() {
+ always_do(fArray[6] != 0.0f || fArray[7] != 0.0f || fArray[8] != 1.0f);
+ always_do(fArray[2] != 0.0f || fArray[5] != 0.0f);
+ }
+private:
+ float fArray[9];
+ typedef ScalarBench INHERITED;
+};
+
+class ForcedIntComparisonBench : public ScalarBench {
+public:
+ ForcedIntComparisonBench(void* param)
+ : INHERITED(param, "compare_forced_int") {
+ init9(fArray);
+ }
+protected:
+ virtual int mulLoopCount() const { return 4; }
+ virtual void performTest() {
+ always_do(SkScalarAs2sCompliment(fArray[6]) |
+ SkScalarAs2sCompliment(fArray[7]) |
+ (SkScalarAs2sCompliment(fArray[8]) - kPersp1Int));
+ always_do(SkScalarAs2sCompliment(fArray[2]) |
+ SkScalarAs2sCompliment(fArray[5]));
+ }
+private:
+ static const int32_t kPersp1Int = 0x3f800000;
+ float fArray[9];
+ typedef ScalarBench INHERITED;
+};
+
+static SkBenchmark* S0(void* p) { return new FloatComparisonBench(p); }
+static SkBenchmark* S1(void* p) { return new ForcedIntComparisonBench(p); }
+
+static BenchRegistry gReg0(S0);
+static BenchRegistry gReg1(S1);