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| author | Ilya Tocar <ilya.tocar@intel.com> | 2017-04-14 13:53:40 -0500 |
|---|---|---|
| committer | Ilya Tocar <ilya.tocar@intel.com> | 2017-06-01 15:46:16 +0000 |
| commit | 3bdc2f3abf0f9cffc8f4e294ef22a23b82e88415 (patch) | |
| tree | 7d3a411585777e41b530a8f7616c296591966c7f /src/runtime | |
| parent | 2f73efa97136a6d4a602a94e87d2a948240e7e8a (diff) | |
| download | go-3bdc2f3abf0f9cffc8f4e294ef22a23b82e88415.tar.xz | |
cmd/compile/internal/gc: speed-up small array comparison
Currently we inline array comparisons for arrays with at most 4 elements.
Compare arrays with small size, but more than 4 elements (e. g. [16]byte)
with larger compares. This provides very slightly smaller binaries,
and results in faster code.
ArrayEqual-6 7.41ns ± 0% 3.17ns ± 0% -57.15% (p=0.000 n=10+10)
For go tool:
global text (code) = -559 bytes (-0.014566%)
This also helps mapaccess1_faststr, and maps in general:
MapDelete/Str/1-6 195ns ± 1% 186ns ± 2% -4.47% (p=0.000 n=10+10)
MapDelete/Str/2-6 211ns ± 1% 177ns ± 1% -16.01% (p=0.000 n=10+10)
MapDelete/Str/4-6 225ns ± 1% 183ns ± 1% -18.49% (p=0.000 n=8+10)
MapStringKeysEight_16-6 31.3ns ± 0% 28.6ns ± 0% -8.63% (p=0.000 n=6+9)
MapStringKeysEight_32-6 29.2ns ± 0% 27.6ns ± 0% -5.45% (p=0.000 n=10+10)
MapStringKeysEight_64-6 29.1ns ± 1% 27.5ns ± 0% -5.46% (p=0.000 n=10+10)
MapStringKeysEight_1M-6 29.1ns ± 1% 27.6ns ± 0% -5.49% (p=0.000 n=10+10)
Change-Id: I9ec98e41b233031e0e96c4e13d86a324f628ed4a
Reviewed-on: https://go-review.googlesource.com/40771
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/hashmap_fast.go | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/src/runtime/hashmap_fast.go b/src/runtime/hashmap_fast.go index ebba001d46..1f9b313219 100644 --- a/src/runtime/hashmap_fast.go +++ b/src/runtime/hashmap_fast.go @@ -252,8 +252,6 @@ func mapaccess1_faststr(t *maptype, h *hmap, ky string) unsafe.Pointer { return add(unsafe.Pointer(b), dataOffset+bucketCnt*2*sys.PtrSize+i*uintptr(t.valuesize)) } // check first 4 bytes - // TODO: on amd64/386 at least, make this compile to one 4-byte comparison instead of - // four 1-byte comparisons. if *((*[4]byte)(key.str)) != *((*[4]byte)(k.str)) { continue } |