Initial contribution
diff --git a/src/testing/allocs.go b/src/testing/allocs.go
new file mode 100644
index 0000000..9ec47bd
--- /dev/null
+++ b/src/testing/allocs.go
@@ -0,0 +1,45 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testing
+
+import (
+ "runtime"
+)
+
+// AllocsPerRun returns the average number of allocations during calls to f.
+// Although the return value has type float64, it will always be an integral value.
+//
+// To compute the number of allocations, the function will first be run once as
+// a warm-up. The average number of allocations over the specified number of
+// runs will then be measured and returned.
+//
+// AllocsPerRun sets GOMAXPROCS to 1 during its measurement and will restore
+// it before returning.
+func AllocsPerRun(runs int, f func()) (avg float64) {
+ defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1))
+
+ // Warm up the function
+ f()
+
+ // Measure the starting statistics
+ var memstats runtime.MemStats
+ runtime.ReadMemStats(&memstats)
+ mallocs := 0 - memstats.Mallocs
+
+ // Run the function the specified number of times
+ for i := 0; i < runs; i++ {
+ f()
+ }
+
+ // Read the final statistics
+ runtime.ReadMemStats(&memstats)
+ mallocs += memstats.Mallocs
+
+ // Average the mallocs over the runs (not counting the warm-up).
+ // We are forced to return a float64 because the API is silly, but do
+ // the division as integers so we can ask if AllocsPerRun()==1
+ // instead of AllocsPerRun()<2.
+ return float64(mallocs / uint64(runs))
+}
