Add ratio calculation to take the ratio of two calculations.

perf/go/parser/parser_test.go

Index: perf/go/parser/parser_test.go
diff --git a/perf/go/parser/parser_test.go b/perf/go/parser/parser_test.go
index 71fbebf5790e8fea8292a02584a59d684212c3ad..57110c6cafd9cc0998fd2ffa236d24ba3ac9c51e 100644
--- a/perf/go/parser/parser_test.go
+++ b/perf/go/parser/parser_test.go
@@ -131,6 +131,19 @@ func TestAve(t *testing.T) {
 	}
 }
 
+func TestRatio(t *testing.T) {
+	ctx := newTestContext()
+	ctx.Tile.Traces["t1"].(*types.PerfTrace).Values = []float64{10, 4, 100, 50}
+	ctx.Tile.Traces["t2"].(*types.PerfTrace).Values = []float64{5, 2, 4, 5}

[jcgregorio, 2014/10/18 00:19:13]

Add a divide by zero case to the tests.

[tfarina, 2014/10/18 03:15:46]

Done.

+
+	_, err := ctx.Eval(`ratio(
+                ave(fill(filter("config=gpu"))),
+                ave(fill(filter("config=8888"))))`)
+	if err != nil {
+		t.Fatalf("Failed to eval ratio() test: %s", err)
+	}

[jcgregorio, 2014/10/18 00:19:13]

Add tests for the values coming from the result of the Eval.

[tfarina, 2014/10/18 03:15:46]

Done.

+}
+
 func TestFill(t *testing.T) {
 	ctx := newTestContext()
 	ctx.Tile.Traces["t1"].(*types.PerfTrace).Values = []float64{1e100, 1e100, 2, 3, 1e100, 5}