diff options
| author | Josh Bleecher Snyder <josharian@gmail.com> | 2017-03-04 16:54:50 -0800 |
|---|---|---|
| committer | Josh Bleecher Snyder <josharian@gmail.com> | 2017-03-08 22:05:52 +0000 |
| commit | 23be728950be7973a4c4852449e1987c64dc2739 (patch) | |
| tree | 24017f1e5ac37c951982858020000bec6adfd6b9 /src/runtime/string.go | |
| parent | 228438e0973b688829fdd601e31352920a5914f4 (diff) | |
| download | go-23be728950be7973a4c4852449e1987c64dc2739.tar.gz go-23be728950be7973a4c4852449e1987c64dc2739.zip | |
runtime: optimize slicebytestostring
Inline rawstringtmp and simplify.
Use memmove instead of copy.
name old time/op new time/op delta
SliceByteToString/1-8 19.4ns ± 2% 14.1ns ± 1% -27.04% (p=0.000 n=20+17)
SliceByteToString/2-8 20.8ns ± 2% 15.5ns ± 2% -25.46% (p=0.000 n=20+20)
SliceByteToString/4-8 20.7ns ± 1% 14.9ns ± 1% -28.30% (p=0.000 n=20+20)
SliceByteToString/8-8 23.2ns ± 1% 17.1ns ± 1% -26.22% (p=0.000 n=19+19)
SliceByteToString/16-8 29.4ns ± 1% 23.6ns ± 1% -19.76% (p=0.000 n=17+20)
SliceByteToString/32-8 31.4ns ± 1% 26.0ns ± 1% -17.11% (p=0.000 n=16+19)
SliceByteToString/64-8 36.1ns ± 0% 30.0ns ± 0% -16.96% (p=0.000 n=16+16)
SliceByteToString/128-8 46.9ns ± 0% 38.9ns ± 0% -17.15% (p=0.000 n=17+19)
Change-Id: I422e688830e4a9bd21897d1f74964625b735f436
Reviewed-on: https://go-review.googlesource.com/37791
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/runtime/string.go')
| -rw-r--r-- | src/runtime/string.go | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/src/runtime/string.go b/src/runtime/string.go index 822adaacf1..0ccc81ee58 100644 --- a/src/runtime/string.go +++ b/src/runtime/string.go @@ -69,7 +69,7 @@ func concatstring5(buf *tmpBuf, a [5]string) string { // Buf is a fixed-size buffer for the result, // it is not nil if the result does not escape. -func slicebytetostring(buf *tmpBuf, b []byte) string { +func slicebytetostring(buf *tmpBuf, b []byte) (str string) { l := len(b) if l == 0 { // Turns out to be a relatively common case. @@ -77,18 +77,26 @@ func slicebytetostring(buf *tmpBuf, b []byte) string { // you find the indices and convert the subslice to string. return "" } - if raceenabled && l > 0 { + if raceenabled { racereadrangepc(unsafe.Pointer(&b[0]), uintptr(l), getcallerpc(unsafe.Pointer(&buf)), funcPC(slicebytetostring)) } - if msanenabled && l > 0 { + if msanenabled { msanread(unsafe.Pointer(&b[0]), uintptr(l)) } - s, c := rawstringtmp(buf, l) - copy(c, b) - return s + + var p unsafe.Pointer + if buf != nil && len(b) <= len(buf) { + p = unsafe.Pointer(buf) + } else { + p = mallocgc(uintptr(len(b)), nil, false) + } + stringStructOf(&str).str = p + stringStructOf(&str).len = len(b) + memmove(p, (*(*slice)(unsafe.Pointer(&b))).array, uintptr(len(b))) + return } // stringDataOnStack reports whether the string's data is |