runtime: Implement faster equals for strings and bytes.

(amd64)
benchmark           old ns/op    new ns/op    delta
BenchmarkEqual0            16            6  -63.15%
BenchmarkEqual9            22            7  -65.37%
BenchmarkEqual32           36            9  -74.91%
BenchmarkEqual4K         2187          120  -94.51%

benchmark            old MB/s     new MB/s  speedup
BenchmarkEqual9        392.22      1134.38    2.89x
BenchmarkEqual32       866.72      3457.39    3.99x
BenchmarkEqual4K      1872.73     33998.87   18.15x

(386)
benchmark           old ns/op    new ns/op    delta
BenchmarkEqual0            16            5  -63.85%
BenchmarkEqual9            22            7  -67.84%
BenchmarkEqual32           34           12  -64.94%
BenchmarkEqual4K         2196          113  -94.85%

benchmark            old MB/s     new MB/s  speedup
BenchmarkEqual9        405.81      1260.18    3.11x
BenchmarkEqual32       919.55      2631.21    2.86x
BenchmarkEqual4K      1864.85     36072.54   19.34x

Update #3751

R=bradfitz, r, khr, dave, remyoudompheng, fullung, minux.ma, ality
CC=golang-dev
https://golang.org/cl/8056043

1 files changed, 1 insertions, 1 deletions

diff --git a/src/pkg/runtime/hashmap.c b/src/pkg/runtime/hashmap.c
index 3f26a157bd..d639be3c3d 100644
--- a/src/pkg/runtime/hashmap.c
+++ b/src/pkg/runtime/hashmap.c
@@ -562,7 +562,7 @@ static uint8 empty_value[MAXVALUESIZE];
 #define HASH_LOOKUP2 runtime·mapaccess2_faststr
 #define KEYTYPE String
 #define HASHFUNC runtime·algarray[ASTRING].hash
-#define EQFUNC(x,y) ((x).len == (y).len && ((x).str == (y).str || runtime·mcmp((x).str, (y).str, (x).len) == 0))
+#define EQFUNC(x,y) ((x).len == (y).len && ((x).str == (y).str || runtime·memeq((x).str, (y).str, (x).len)))
 #define QUICKEQ(x) ((x).len < 32)
 #include "hashmap_fast.c"