test/mapnan.go: add regression test for non-empty interfaces.

LGTM=rsc, khr
R=rsc, khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/126720043

test/map.go

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file.
 
 // Test maps, almost exhaustively.
-// NaN complexity test is in mapnan.go.
+// Complexity (linearity) test is in maplinear.go.
 
 package main
 

test/mapnan.go → test/maplinear.go

@@ -5,7 +5,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Test that NaNs in maps don't go quadratic.
+// Test that maps don't go quadratic for NaNs and other values.
 
 package main
 
@@ -15,42 +15,129 @@ import (
 	"time"
 )
 
-func main() {
+// checkLinear asserts that the running time of f(n) is in O(n).
+// tries is the initial number of iterations.
+func checkLinear(typ string, tries int, f func(n int)) {
+	// Depending on the machine and OS, this test might be too fast
+	// to measure with accurate enough granularity. On failure,
+	// make it run longer, hoping that the timing granularity
+	// is eventually sufficient.
 
-	// Test that NaNs in maps don't go quadratic.
-	t := func(n int) time.Duration {
+	timeF := func(n int) time.Duration {
 		t1 := time.Now()
-		m := map[float64]int{}
-		nan := math.NaN()
-		for i := 0; i < n; i++ {
-			m[nan] = 1
-		}
-		if len(m) != n {
-			panic("wrong size map after nan insertion")
-		}
+		f(n)
 		return time.Since(t1)
 	}
 
-	// Depending on the machine and OS, this test might be too fast
-	// to measure with accurate enough granularity. On failure,
-	// make it run longer, hoping that the timing granularity
-	// is eventually sufficient.
+	t0 := time.Now()
 
-	n := 30000 // ~8ms user time on a Mid 2011 MacBook Air (1.8 GHz Core i7)
+	n := tries
 	fails := 0
 	for {
-		t1 := t(n)
-		t2 := t(2 * n)
+		t1 := timeF(n)
+		t2 := timeF(2 * n)
+
 		// should be 2x (linear); allow up to 3x
 		if t2 < 3*t1 {
+			if false {
+				fmt.Println(typ, "\t", time.Since(t0))
+			}
 			return
 		}
 		fails++
 		if fails == 6 {
-			panic(fmt.Sprintf("too slow: %d inserts: %v; %d inserts: %v\n", n, t1, 2*n, t2))
+			panic(fmt.Sprintf("%s: too slow: %d inserts: %v; %d inserts: %v\n",
+				typ, n, t1, 2*n, t2))
 		}
 		if fails < 4 {
 			n *= 2
 		}
 	}
 }
+
+type I interface {
+	f()
+}
+
+type C int
+
+func (C) f() {}
+
+func main() {
+	// NaNs. ~31ms on a 1.6GHz Zeon.
+	checkLinear("NaN", 30000, func(n int) {
+		m := map[float64]int{}
+		nan := math.NaN()
+		for i := 0; i < n; i++ {
+			m[nan] = 1
+		}
+		if len(m) != n {
+			panic("wrong size map after nan insertion")
+		}
+	})
+
+	// ~6ms on a 1.6GHz Zeon.
+	checkLinear("eface", 10000, func(n int) {
+		m := map[interface{}]int{}
+		for i := 0; i < n; i++ {
+			m[i] = 1
+		}
+	})
+
+	// ~7ms on a 1.6GHz Zeon.
+	// Regression test for CL 119360043.
+	checkLinear("iface", 10000, func(n int) {
+		m := map[I]int{}
+		for i := 0; i < n; i++ {
+			m[C(i)] = 1
+		}
+	})
+
+	// ~6ms on a 1.6GHz Zeon.
+	checkLinear("int", 10000, func(n int) {
+		m := map[int]int{}
+		for i := 0; i < n; i++ {
+			m[i] = 1
+		}
+	})
+
+	// ~18ms on a 1.6GHz Zeon.
+	checkLinear("string", 10000, func(n int) {
+		m := map[string]int{}
+		for i := 0; i < n; i++ {
+			m[fmt.Sprint(i)] = 1
+		}
+	})
+
+	// ~6ms on a 1.6GHz Zeon.
+	checkLinear("float32", 10000, func(n int) {
+		m := map[float32]int{}
+		for i := 0; i < n; i++ {
+			m[float32(i)] = 1
+		}
+	})
+
+	// ~6ms on a 1.6GHz Zeon.
+	checkLinear("float64", 10000, func(n int) {
+		m := map[float64]int{}
+		for i := 0; i < n; i++ {
+			m[float64(i)] = 1
+		}
+	})
+
+	// ~22ms on a 1.6GHz Zeon.
+	checkLinear("complex64", 10000, func(n int) {
+		m := map[complex64]int{}
+		for i := 0; i < n; i++ {
+			m[complex(float32(i), float32(i))] = 1
+		}
+	})
+
+	// ~32ms on a 1.6GHz Zeon.
+	checkLinear("complex128", 10000, func(n int) {
+		m := map[complex128]int{}
+		for i := 0; i < n; i++ {
+			m[complex(float64(i), float64(i))] = 1
+		}
+	})
+}