runtime: specialize memhash32 and memhash64

AMD64 with AES support disabled:
name                old time/op    new time/op    delta
MapPopulate/1         78.0ns ± 1%    75.5ns ± 1%   -3.17%  (p=0.000 n=10+9)
MapPopulate/10         764ns ± 2%     673ns ± 2%  -11.91%  (p=0.000 n=10+10)
MapPopulate/100       9.52µs ± 1%    8.54µs ± 1%  -10.37%  (p=0.000 n=8+10)
MapPopulate/1000       116µs ± 2%     103µs ± 1%  -10.40%  (p=0.000 n=10+8)
MapPopulate/10000     1.01ms ± 1%    0.90ms ± 1%  -10.70%  (p=0.000 n=10+10)
MapPopulate/100000    9.81ms ± 1%    8.67ms ± 2%  -11.54%  (p=0.000 n=10+10)

386 with AES support disabled:
name                old time/op    new time/op    delta
MapPopulate/1         95.3ns ± 1%    90.6ns ± 1%  -4.95%  (p=0.000 n=10+9)
MapPopulate/10         983ns ± 2%     912ns ± 1%  -7.18%  (p=0.000 n=10+10)
MapPopulate/100       11.9µs ± 2%    11.2µs ± 1%  -6.01%  (p=0.000 n=10+10)
MapPopulate/1000       140µs ± 1%     131µs ± 1%  -6.19%  (p=0.000 n=10+10)
MapPopulate/10000     1.26ms ± 2%    1.18ms ± 1%  -5.93%  (p=0.000 n=9+10)
MapPopulate/100000    12.1ms ± 2%    11.4ms ± 1%  -5.48%  (p=0.000 n=10+10)

Fixes #21539

Change-Id: Ice128c947c9a6a294800d6a5250d82045eb70b55
Reviewed-on: https://go-review.googlesource.com/59352
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/runtime/hash_test.go b/src/runtime/hash_test.go
index a6f3cdbdbe..1400579cda 100644
--- a/src/runtime/hash_test.go
+++ b/src/runtime/hash_test.go
@@ -14,6 +14,40 @@ import (
 	"unsafe"
 )
 
+func TestMemHash32Equality(t *testing.T) {
+	if *UseAeshash {
+		t.Skip("skipping since AES hash implementation is used")
+	}
+	var b [4]byte
+	r := rand.New(rand.NewSource(1234))
+	seed := uintptr(r.Uint64())
+	for i := 0; i < 100; i++ {
+		randBytes(r, b[:])
+		got := MemHash32(unsafe.Pointer(&b), seed)
+		want := MemHash(unsafe.Pointer(&b), seed, 4)
+		if got != want {
+			t.Errorf("MemHash32(%x, %v) = %v; want %v", b, seed, got, want)
+		}
+	}
+}
+
+func TestMemHash64Equality(t *testing.T) {
+	if *UseAeshash {
+		t.Skip("skipping since AES hash implementation is used")
+	}
+	var b [8]byte
+	r := rand.New(rand.NewSource(1234))
+	seed := uintptr(r.Uint64())
+	for i := 0; i < 100; i++ {
+		randBytes(r, b[:])
+		got := MemHash64(unsafe.Pointer(&b), seed)
+		want := MemHash(unsafe.Pointer(&b), seed, 8)
+		if got != want {
+			t.Errorf("MemHash64(%x, %v) = %v; want %v", b, seed, got, want)
+		}
+	}
+}
+
 // Smhasher is a torture test for hash functions.
 // https://code.google.com/p/smhasher/
 // This code is a port of some of the Smhasher tests to Go.