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cmd/compile: generate makechan calls with int arguments

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Where possible generate calls to runtime makechan with int arguments
during compile time instead of makechan with int64 arguments.

This eliminates converting arguments for calls to makechan with
int64 arguments for platforms where int64 values do not fit into
arguments of type int.

A similar optimization for makeslice was introduced in CL
golang.org/cl/27851.

386:
name                old time/op  new time/op  delta
MakeChan/Byte       52.4ns ± 6%  45.0ns ± 1%  -14.14%  (p=0.000 n=10+10)
MakeChan/Int        54.5ns ± 1%  49.1ns ± 1%   -9.87%  (p=0.000 n=10+10)
MakeChan/Ptr         150ns ± 1%   143ns ± 0%   -4.38%  (p=0.000 n=9+7)
MakeChan/Struct/0   49.2ns ± 2%  43.2ns ± 2%  -12.27%  (p=0.000 n=10+10)
MakeChan/Struct/32  81.7ns ± 2%  76.2ns ± 1%   -6.71%  (p=0.000 n=10+10)
MakeChan/Struct/40  88.4ns ± 2%  82.5ns ± 2%   -6.60%  (p=0.000 n=10+10)

AMD64:
name                old time/op  new time/op  delta
MakeChan/Byte       83.4ns ± 8%  80.8ns ± 3%    ~     (p=0.171 n=10+10)
MakeChan/Int         101ns ± 3%   101ns ± 2%    ~     (p=0.412 n=10+10)
MakeChan/Ptr         128ns ± 1%   128ns ± 1%    ~     (p=0.191 n=10+10)
MakeChan/Struct/0   67.6ns ± 3%  68.7ns ± 4%    ~     (p=0.224 n=10+10)
MakeChan/Struct/32   138ns ± 1%   139ns ± 1%    ~     (p=0.185 n=10+9)
MakeChan/Struct/40   154ns ± 1%   154ns ± 1%  -0.55%  (p=0.027 n=10+9)

Change-Id: Ie854cb066007232c5e9f71ea7d6fe27e81a9c050
Reviewed-on: https://go-review.googlesource.com/55140
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Martin Möhrmann 2017-08-13 20:03:02 +02:00
parent 4c55774304
commit 8a6e51aede
8 changed files with 246 additions and 95 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/reflect/value.go
View file

@ -2072,7 +2072,7 @@ func MakeChan(typ Type, buffer int) Value {
if typ.ChanDir() != BothDir {
panic("reflect.MakeChan: unidirectional channel type")
}
ch := makechan(typ.(*rtype), uint64(buffer))
ch := makechan(typ.(*rtype), buffer)
return Value{typ.common(), ch, flag(Chan)}
}
@ -2480,7 +2480,7 @@ func chanrecv(ch unsafe.Pointer, nb bool, val unsafe.Pointer) (selected, receive
//go:noescape
func chansend(ch unsafe.Pointer, val unsafe.Pointer, nb bool) bool
func makechan(typ *rtype, size uint64) (ch unsafe.Pointer)
func makechan(typ *rtype, size int) (ch unsafe.Pointer)
func makemap(t *rtype, cap int) (m unsafe.Pointer)
//go:noescape