Commits · bf6530a25b07b6cbde4f1d7b25e549675340dec1 · Kirill Smelkov / go

26 Apr, 2018 9 commits

cmd/asm: add VSRI instruction on ARM64 · bf6530a2

Balaram Makam authored Apr 25, 2018

This change provides VSRI instruction for ChaCha20Poly1305 implementation.

Change-Id: Ifee727b6f3982b629b44a67cac5bbe87ca59027b
Reviewed-on: https://go-review.googlesource.com/109342
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

bf6530a2

cmd/link: fix test flag · b4ac0297

Keith Randall authored Apr 25, 2018

Doesn't cause an error, see #25085.
But we should fix it nonetheless.

Change-Id: I7b6799e0a95475202cacefc3a7f02487e61bfd31
Reviewed-on: https://go-review.googlesource.com/109355Reviewed-by: Heschi Kreinick <heschi@google.com>

b4ac0297

cmd/compile: optimize ARM64 code with CMN/TST · f524268c

Balaram Makam authored Apr 24, 2018

Use CMN/TST to simplify comparisons. This can reduce the
register pressure by removing single def/use registers for example:
ADDW R0, R1, R8 -> CMNW R1, R0 ; CMN is an alias of ADDS.
CBZW R8, label -> BEQ label ; single def/use of R8 removed.

Little change in performance of go1 benchmark on Amberwing:
name old time/op new time/op delta
RegexpMatchEasy0_32 247ns ± 0% 246ns ± 0% -0.40% (p=0.008 n=5+5)
RegexpMatchEasy0_1K 581ns ± 0% 580ns ± 0% ~ (p=0.079 n=4+5)
RegexpMatchEasy1_32 244ns ± 0% 243ns ± 0% -0.41% (p=0.008 n=5+5)
RegexpMatchEasy1_1K 804ns ± 0% 806ns ± 0% +0.25% (p=0.016 n=5+4)
RegexpMatchMedium_32 313ns ± 0% 311ns ± 0% -0.64% (p=0.008 n=5+5)
RegexpMatchMedium_1K 52.2µs ± 0% 51.9µs ± 0% -0.51% (p=0.008 n=5+5)
RegexpMatchHard_32 2.76µs ± 3% 2.74µs ± 0% ~ (p=0.683 n=5+5)
RegexpMatchHard_1K 78.8µs ± 0% 78.9µs ± 0% +0.04% (p=0.008 n=5+5)
FmtFprintfEmpty 58.6ns ± 0% 57.7ns ± 0% -1.54% (p=0.008 n=5+5)
FmtFprintfString 118ns ± 0% 115ns ± 0% -2.54% (p=0.008 n=5+5)
FmtFprintfInt 119ns ± 0% 119ns ± 0% ~ (all equal)
FmtFprintfIntInt 192ns ± 0% 192ns ± 0% ~ (all equal)
FmtFprintfPrefixedInt 224ns ± 0% 205ns ± 0% -8.48% (p=0.008 n=5+5)
FmtFprintfFloat 336ns ± 0% 333ns ± 1% ~ (p=0.683 n=5+5)
FmtManyArgs 779ns ± 1% 760ns ± 1% -2.41% (p=0.008 n=5+5)
Gzip 437ms ± 0% 436ms ± 0% -0.27% (p=0.008 n=5+5)
HTTPClientServer 90.1µs ± 1% 91.1µs ± 0% +1.19% (p=0.008 n=5+5)
JSONEncode 20.1ms ± 0% 20.2ms ± 1% ~ (p=0.690 n=5+5)
JSONDecode 94.5ms ± 1% 94.1ms ± 1% ~ (p=0.095 n=5+5)
Mandelbrot200 5.37ms ± 0% 5.37ms ± 0% ~ (p=0.421 n=5+5)
TimeParse 450ns ± 0% 446ns ± 0% -0.89% (p=0.000 n=5+4)
TimeFormat 483ns ± 1% 473ns ± 0% -2.19% (p=0.008 n=5+5)
Template 90.6ms ± 0% 89.7ms ± 0% -0.93% (p=0.008 n=5+5)
GoParse 5.97ms ± 0% 6.01ms ± 0% +0.65% (p=0.008 n=5+5)
BinaryTree17 11.8s ± 0% 11.7s ± 0% -0.28% (p=0.016 n=5+5)
Revcomp 669ms ± 0% 669ms ± 0% ~ (p=0.222 n=5+5)
Fannkuch11 3.28s ± 0% 3.34s ± 0% +1.72% (p=0.016 n=4+5)
[Geo mean] 46.6µs 46.3µs -0.74%

name old speed new speed delta
RegexpMatchEasy0_32 129MB/s ± 0% 130MB/s ± 0% +0.32% (p=0.016 n=5+4)
RegexpMatchEasy0_1K 1.76GB/s ± 0% 1.76GB/s ± 0% +0.13% (p=0.016 n=4+5)
RegexpMatchEasy1_32 131MB/s ± 0% 132MB/s ± 0% +0.32% (p=0.008 n=5+5)
RegexpMatchEasy1_1K 1.27GB/s ± 0% 1.27GB/s ± 0% -0.24% (p=0.016 n=5+4)
RegexpMatchMedium_32 3.19MB/s ± 0% 3.21MB/s ± 0% +0.63% (p=0.008 n=5+5)
RegexpMatchMedium_1K 19.6MB/s ± 0% 19.7MB/s ± 0% +0.51% (p=0.029 n=4+4)
RegexpMatchHard_32 11.6MB/s ± 2% 11.7MB/s ± 0% ~ (p=1.000 n=5+5)
RegexpMatchHard_1K 13.0MB/s ± 0% 13.0MB/s ± 0% ~ (p=0.079 n=4+5)
Gzip 44.4MB/s ± 0% 44.5MB/s ± 0% +0.27% (p=0.008 n=5+5)
JSONEncode 96.4MB/s ± 0% 96.2MB/s ± 1% ~ (p=0.579 n=5+5)
JSONDecode 20.5MB/s ± 1% 20.6MB/s ± 1% ~ (p=0.111 n=5+5)
Template 21.4MB/s ± 0% 21.6MB/s ± 0% +0.94% (p=0.008 n=5+5)
GoParse 9.70MB/s ± 0% 9.63MB/s ± 0% -0.68% (p=0.016 n=4+5)
Revcomp 380MB/s ± 0% 380MB/s ± 0% ~ (p=0.222 n=5+5)
[Geo mean] 55.3MB/s 55.4MB/s +0.23%

Change-Id: I2e5338138991d9bc984e67b51212aa5d1b0f2a6b
Reviewed-on: https://go-review.googlesource.com/97335Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>

f524268c

cmd/compile, cmd/internal/obj/ppc64: make math.Round an intrinsic on ppc64x · ebb67d99

Carlos Eduardo Seo authored Mar 02, 2018

This change implements math.Round as an intrinsic on ppc64x so it can be
done using a single instruction.

benchmark                   old ns/op     new ns/op     delta
BenchmarkRound-16           2.60          0.69          -73.46%

Change-Id: I9408363e96201abdfc73ced7bcd5f0c29db006a8
Reviewed-on: https://go-review.googlesource.com/109395
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

ebb67d99

cmd/compile: allow SSA of multi-field structs while instrumenting · 736390c2

Matthew Dempsky authored Apr 25, 2018

When we moved racewalk to buildssa, we disabled SSA of structs with
2-4 fields while instrumenting because it caused false dependencies
because for "x.f" we would emit

    (StructSelect (Load (Addr x)) "f")

Even though we later simplify this to

    (Load (OffPtr (Addr x) "f"))

the instrumentation saw a load of x in its entirety and would issue
appropriate race/msan calls.

The fix taken here is to directly emit the OffPtr form when x.f is
addressable and can't be represented in SSA form.

Change-Id: I0caf37bced52e9c16937466b0ac8cab6d356e525
Reviewed-on: https://go-review.googlesource.com/109360
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

736390c2

runtime: FreeBSD fast clock_gettime HPET timecounter support · 58c231f2

Yuval Pavel Zholkover authored Apr 19, 2018

This is a followup for CL 93156.

Fixes #22942.

Change-Id: Ic6e2de44011d041b91454353a6f2e3b0cf590060
Reviewed-on: https://go-review.googlesource.com/108095
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

58c231f2

cmd/go: respect vet typecheck failures again · 279b530d

Russ Cox authored Apr 20, 2018

Now that #18395 is fixed, let's see if we can insist
on vet during go test being able to type-check
packages again.

Change-Id: Iaa55a4d9c582ba743df2347d28c24f130e16e406
Reviewed-on: https://go-review.googlesource.com/108555
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

279b530d

cmd/go: disambiguate for-test packages in failure output · 1a64025f

Russ Cox authored Apr 19, 2018

Now that we can tell when a package is a split-off copy
for testing, show that in the build failures.
For example, instead of:

	# regexp/syntax
	../../regexp/syntax/parse.go:9:2: can't find import: "strings"
	# path/filepath
	../../path/filepath/match.go:12:2: can't find import: "strings"
	# flag
	../../flag/flag.go:75:2: can't find import: "strings"

we now print

	# regexp/syntax [strings.test]
	../../regexp/syntax/parse.go:9:2: can't find import: "strings"
	# path/filepath [strings.test]
	../../path/filepath/match.go:12:2: can't find import: "strings"
	# flag [strings.test]
	../../flag/flag.go:75:2: can't find import: "strings"

which gives more of a hint about what is wrong.

This is especially helpful if a package is being built multiple times,
since it explains why an error might appear multiple times:

	$ go test regexp encoding/json
	# regexp
	../../regexp/exec.go:12:9: undefined: x
	# regexp [regexp.test]
	../../regexp/exec.go:12:9: undefined: x
	FAIL	regexp [build failed]
	FAIL	encoding/json [build failed]
	$

Change-Id: Ie325796f6c3cf0e23f306066be8e65a30cb6b939
Reviewed-on: https://go-review.googlesource.com/108155
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

1a64025f

cmd/go: add go list -test to describe test binaries · 296e6765

Russ Cox authored Apr 18, 2018

Tools should be able to ask cmd/go about the dependency
graph for test binaries instead of reinventing it themselves.
Allow them to do so, with the new list -test flag.

This also fixes and tests for a bug introduced in CL 104315
that was not properly splitting dependencies on the path
between package main and the package being tested.

Change-Id: I29eb454c82893f5ee70252aaaecd9fa376eaf3c8
Reviewed-on: https://go-review.googlesource.com/107916
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

296e6765

25 Apr, 2018 22 commits

cmd/compile: use intrinsic for LeadingZeros8 on amd64 · c5f0104d

Josh Bleecher Snyder authored Apr 23, 2018

The previous change sped up the pure computation form of LeadingZeros8.
This places it somewhat close to the table lookup form.
Depending on something that varies from toolchain to toolchain
(alignment, perhaps?), the slowdown from ditching the table lookup
is either 20% or 5%.

This benchmark is the best case scenario for the table lookup:
It is in the L1 cache already.

I think we're close enough that we can switch to the computational version,
and trust that the memory effects and binary size savings will be worth it.

Code:

func f8(x uint8)   { z = bits.LeadingZeros8(x) }

Before:

"".f8 STEXT nosplit size=34 args=0x8 locals=0x0
	0x0000 00000 (x.go:7)	TEXT	"".f8(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:7)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:7)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:7)	MOVBLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:7)	MOVBLZX	AL, AX
	0x0008 00008 (x.go:7)	LEAQ	math/bits.len8tab(SB), CX
	0x000f 00015 (x.go:7)	MOVBLZX	(CX)(AX*1), AX
	0x0013 00019 (x.go:7)	ADDQ	$-8, AX
	0x0017 00023 (x.go:7)	NEGQ	AX
	0x001a 00026 (x.go:7)	MOVQ	AX, "".z(SB)
	0x0021 00033 (x.go:7)	RET

After:

"".f8 STEXT nosplit size=30 args=0x8 locals=0x0
	0x0000 00000 (x.go:7)	TEXT	"".f8(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:7)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:7)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:7)	MOVBLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:7)	MOVBLZX	AL, AX
	0x0008 00008 (x.go:7)	LEAL	1(AX)(AX*1), AX
	0x000c 00012 (x.go:7)	BSRL	AX, AX
	0x000f 00015 (x.go:7)	ADDQ	$-8, AX
	0x0013 00019 (x.go:7)	NEGQ	AX
	0x0016 00022 (x.go:7)	MOVQ	AX, "".z(SB)
	0x001d 00029 (x.go:7)	RET

Change-Id: Icc7db50a7820fb9a3da8a816d6b6940d7f8e193e
Reviewed-on: https://go-review.googlesource.com/108942
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

c5f0104d

cmd/compile: optimize LeadingZeros(16|32) on amd64 · 1d321ada

Josh Bleecher Snyder authored Apr 23, 2018

Introduce Len8 and Len16 ops and provide optimized lowerings for them.
amd64 only for this CL, although it wouldn't surprise me
if other architectures also admit of optimized lowerings.

Also use and optimize the Len32 lowering, along the same lines.

Leave Len8 unused for the moment; a subsequent CL will enable it.

For 16 and 32 bits, this leads to a speed-up.

name              old time/op  new time/op  delta
LeadingZeros16-8  1.42ns ± 5%  1.23ns ± 5%  -13.42%  (p=0.000 n=20+20)
LeadingZeros32-8  1.25ns ± 5%  1.03ns ± 5%  -17.63%  (p=0.000 n=20+16)

Code:

func f16(x uint16) { z = bits.LeadingZeros16(x) }
func f32(x uint32) { z = bits.LeadingZeros32(x) }

Before:

"".f16 STEXT nosplit size=38 args=0x8 locals=0x0
	0x0000 00000 (x.go:8)	TEXT	"".f16(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:8)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:8)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:8)	MOVWLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:8)	MOVWLZX	AX, AX
	0x0008 00008 (x.go:8)	BSRQ	AX, AX
	0x000c 00012 (x.go:8)	MOVQ	$-1, CX
	0x0013 00019 (x.go:8)	CMOVQEQ	CX, AX
	0x0017 00023 (x.go:8)	ADDQ	$-15, AX
	0x001b 00027 (x.go:8)	NEGQ	AX
	0x001e 00030 (x.go:8)	MOVQ	AX, "".z(SB)
	0x0025 00037 (x.go:8)	RET

"".f32 STEXT nosplit size=34 args=0x8 locals=0x0
	0x0000 00000 (x.go:9)	TEXT	"".f32(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:9)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:9)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:9)	MOVL	"".x+8(SP), AX
	0x0004 00004 (x.go:9)	BSRQ	AX, AX
	0x0008 00008 (x.go:9)	MOVQ	$-1, CX
	0x000f 00015 (x.go:9)	CMOVQEQ	CX, AX
	0x0013 00019 (x.go:9)	ADDQ	$-31, AX
	0x0017 00023 (x.go:9)	NEGQ	AX
	0x001a 00026 (x.go:9)	MOVQ	AX, "".z(SB)
	0x0021 00033 (x.go:9)	RET

After:

"".f16 STEXT nosplit size=30 args=0x8 locals=0x0
	0x0000 00000 (x.go:8)	TEXT	"".f16(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:8)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:8)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:8)	MOVWLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:8)	MOVWLZX	AX, AX
	0x0008 00008 (x.go:8)	LEAL	1(AX)(AX*1), AX
	0x000c 00012 (x.go:8)	BSRL	AX, AX
	0x000f 00015 (x.go:8)	ADDQ	$-16, AX
	0x0013 00019 (x.go:8)	NEGQ	AX
	0x0016 00022 (x.go:8)	MOVQ	AX, "".z(SB)
	0x001d 00029 (x.go:8)	RET

"".f32 STEXT nosplit size=28 args=0x8 locals=0x0
	0x0000 00000 (x.go:9)	TEXT	"".f32(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:9)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:9)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:9)	MOVL	"".x+8(SP), AX
	0x0004 00004 (x.go:9)	LEAQ	1(AX)(AX*1), AX
	0x0009 00009 (x.go:9)	BSRQ	AX, AX
	0x000d 00013 (x.go:9)	ADDQ	$-32, AX
	0x0011 00017 (x.go:9)	NEGQ	AX
	0x0014 00020 (x.go:9)	MOVQ	AX, "".z(SB)
	0x001b 00027 (x.go:9)	RET

Change-Id: I6c93c173752a7bfdeab8be30777ae05a736e1f4b
Reviewed-on: https://go-review.googlesource.com/108941
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Keith Randall <khr@golang.org>

1d321ada

cmd/compile: optimize TrailingZeros(8|16) on amd64 · 54dbab52

Josh Bleecher Snyder authored Apr 23, 2018

Introduce Ctz8 and Ctz16 ops and provide optimized lowerings for them.
amd64 only for this CL, although it wouldn't surprise me
if other architectures also admit of optimized lowerings.

name               old time/op  new time/op  delta
TrailingZeros8-8   1.33ns ± 6%  0.84ns ± 3%  -36.90%  (p=0.000 n=20+20)
TrailingZeros16-8  1.26ns ± 5%  0.84ns ± 5%  -33.50%  (p=0.000 n=20+18)

Code:

func f8(x uint8)   { z = bits.TrailingZeros8(x) }
func f16(x uint16) { z = bits.TrailingZeros16(x) }

Before:

"".f8 STEXT nosplit size=34 args=0x8 locals=0x0
	0x0000 00000 (x.go:7)	TEXT	"".f8(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:7)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:7)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:7)	MOVBLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:7)	MOVBLZX	AL, AX
	0x0008 00008 (x.go:7)	BTSQ	$8, AX
	0x000d 00013 (x.go:7)	BSFQ	AX, AX
	0x0011 00017 (x.go:7)	MOVL	$64, CX
	0x0016 00022 (x.go:7)	CMOVQEQ	CX, AX
	0x001a 00026 (x.go:7)	MOVQ	AX, "".z(SB)
	0x0021 00033 (x.go:7)	RET

"".f16 STEXT nosplit size=34 args=0x8 locals=0x0
	0x0000 00000 (x.go:8)	TEXT	"".f16(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:8)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:8)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:8)	MOVWLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:8)	MOVWLZX	AX, AX
	0x0008 00008 (x.go:8)	BTSQ	$16, AX
	0x000d 00013 (x.go:8)	BSFQ	AX, AX
	0x0011 00017 (x.go:8)	MOVL	$64, CX
	0x0016 00022 (x.go:8)	CMOVQEQ	CX, AX
	0x001a 00026 (x.go:8)	MOVQ	AX, "".z(SB)
	0x0021 00033 (x.go:8)	RET

After:

"".f8 STEXT nosplit size=20 args=0x8 locals=0x0
	0x0000 00000 (x.go:7)	TEXT	"".f8(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:7)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:7)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:7)	MOVBLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:7)	BTSL	$8, AX
	0x0009 00009 (x.go:7)	BSFL	AX, AX
	0x000c 00012 (x.go:7)	MOVQ	AX, "".z(SB)
	0x0013 00019 (x.go:7)	RET

"".f16 STEXT nosplit size=20 args=0x8 locals=0x0
	0x0000 00000 (x.go:8)	TEXT	"".f16(SB), NOSPLIT, $0-8
	0x0000 00000 (x.go:8)	FUNCDATA	$0, gclocals·2a5305abe05176240e61b8620e19a815(SB)
	0x0000 00000 (x.go:8)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:8)	MOVWLZX	"".x+8(SP), AX
	0x0005 00005 (x.go:8)	BTSL	$16, AX
	0x0009 00009 (x.go:8)	BSFL	AX, AX
	0x000c 00012 (x.go:8)	MOVQ	AX, "".z(SB)
	0x0013 00019 (x.go:8)	RET

Change-Id: I0551e357348de2b724737d569afd6ac9f5c3aa11
Reviewed-on: https://go-review.googlesource.com/108940
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Keith Randall <khr@golang.org>

54dbab52

cmd/go/internal/load: split test logic out of pkg.go into test.go · 90083e65

Russ Cox authored Apr 18, 2018

It's going to grow.

Change-Id: I4f5d3cce6e03250508d1ae0981a6d82a4192ae31
Reviewed-on: https://go-review.googlesource.com/107915
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

90083e65

cmd/go: add go list -deps · 90e860f1

Russ Cox authored Apr 18, 2018

This gives an easy way to query properties of all the deps
of a set of packages, in a single go list invocation.
Go list has already done the hard work of loading these
packages, so exposing them is more efficient than
requiring a second invocation.

This will be helpful for tools asking cmd/go about build
information.

Change-Id: I90798e386246b24aad92dd13cb9e3788c7d30e91
Reviewed-on: https://go-review.googlesource.com/107776
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

90e860f1

misc/cgo/test: log error value in testSigprocmask · 9c9ed9aa

Ian Lance Taylor authored Apr 25, 2018

The test has been flaky, probably due to EAGAIN, but let's find out
for sure.

Updates #25078

Change-Id: I5a5b14bfc52cb43f25f07ca7d207b61ae9d4f944
Reviewed-on: https://go-review.googlesource.com/109359
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

9c9ed9aa

cmd/compile: fix format error · d3ff5090

Russ Cox authored Apr 25, 2018

Found by pending CL to make cmd/vet auto-detect printf wrappers.

Change-Id: I6b5ba8f9c301dd2d7086c152cf2e54a68b012208
Reviewed-on: https://go-review.googlesource.com/109345
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

d3ff5090

encoding/base64: fix format error · 50a58396

Russ Cox authored Apr 25, 2018

Found by pending CL to make cmd/vet auto-detect printf wrappers.

Change-Id: I2ad06647b7b41cf68859820a60eeac2e689ca2e6
Reviewed-on: https://go-review.googlesource.com/109344
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

50a58396

go/types: fix format errors · 932794cb

Russ Cox authored Apr 25, 2018

Found by pending CL to make cmd/vet auto-detect printf wrappers.

Change-Id: I1928a5bcd7885cdd950ce81b7d0ba07fbad3bf88
Reviewed-on: https://go-review.googlesource.com/109343
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

932794cb

cmd/go: fix go list .Stale computation · 9e0e6981

Russ Cox authored Apr 18, 2018

If X depends on Y and X was installed but Y is only present in the cache
(as happens when you "go install X") then we should report X as up-to-date,
not as stale.

This applies whether X is a package or a main binary.

Fixes #24558.
Fixes #23818.

Change-Id: I26a0b375b1f7f7ac909cc0db68e92f4e04529208
Reviewed-on: https://go-review.googlesource.com/107957
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

9e0e6981

cmd/compile/internal/types: remove Field.Funarg · 7500b299

Matthew Dempsky authored Apr 24, 2018

Passes toolstash-check.

Change-Id: Idc00f15e369cad62cb8f7a09fd0ef09abd3fcdef
Reviewed-on: https://go-review.googlesource.com/109356
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

7500b299

go/types: use correct (file) scopes when computing interface method sets · 73becbf9

Robert Griesemer authored Apr 24, 2018

This was already partially fixed by commit 99843e22
(https://go-review.googlesource.com/c/go/+/96376); but
we missed a couple of places where we also need to
propagate the scope.

Fixes #25008.

Change-Id: I041fa74d1f6d3b5a8edb922efa126ff1dacd7900
Reviewed-on: https://go-review.googlesource.com/109139Reviewed-by: Alan Donovan <adonovan@google.com>

73becbf9

cmd/go: avoid infinite loop in go list -json -e on import cycle · f2df0ec7

Russ Cox authored Apr 18, 2018

Don't chase import cycles forever preparing list JSON.

Fixes #24086.

Change-Id: Ia1139d0c8d813d068c367a8baee59d240a545617
Reviewed-on: https://go-review.googlesource.com/108016
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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f2df0ec7

cmd/compile/internal/ssa: tweak branchelim cost model on amd64 · 25813f9f

Ilya Tocar authored Apr 18, 2018

Currently branchelim is too aggressive in converting branches to
conditinal movs. On most x86 cpus resulting cmov* are more expensive than
most simple instructions, because they have a latency of 2, instead of 1,
So by teaching branchelim to limit number of CondSelects and consider possible
need to recalculate flags, we can archive huge speed-ups (fix big regressions).
In package strings:

ToUpper/#00-6 10.9ns ± 1% 11.8ns ± 1% +8.29% (p=0.000 n=10+10)
ToUpper/ONLYUPPER-6 27.9ns ± 0% 27.8ns ± 1% ~ (p=0.106 n=9+10)
ToUpper/abc-6 90.3ns ± 2% 90.3ns ± 1% ~ (p=0.956 n=10+10)
ToUpper/AbC123-6 110ns ± 1% 113ns ± 2% +3.19% (p=0.000 n=10+10)
ToUpper/azAZ09_-6 109ns ± 2% 110ns ± 1% ~ (p=0.174 n=10+10)
ToUpper/longStrinGwitHmixofsmaLLandcAps-6 228ns ± 1% 233ns ± 2% +2.11% (p=0.000 n=10+10)
ToUpper/longɐstringɐwithɐnonasciiⱯchars-6 907ns ± 1% 709ns ± 2% -21.85% (p=0.000 n=10+10)
ToUpper/ɐɐɐɐɐ-6 793ns ± 2% 562ns ± 2% -29.06% (p=0.000 n=10+10)

In fmt:

SprintfQuoteString-6 272ns ± 2% 195ns ± 4% -28.39% (p=0.000 n=10+10)

And in archive/zip:

CompressedZipGarbage-6 4.00ms ± 0% 4.03ms ± 0% +0.71% (p=0.000 n=10+10)
Zip64Test-6 27.5ms ± 1% 24.2ms ± 0% -12.01% (p=0.000 n=10+10)
Zip64TestSizes/4096-6 10.4µs ±12% 10.7µs ± 8% ~ (p=0.068 n=10+8)
Zip64TestSizes/1048576-6 79.0µs ± 3% 70.2µs ± 2% -11.14% (p=0.000 n=10+10)
Zip64TestSizes/67108864-6 4.64ms ± 1% 4.11ms ± 1% -11.43% (p=0.000 n=10+10)

As far as I can tell, no cases with significant gain from cmov have regressed.

On go1 it looks like most changes are unrelated, but I've verified that
TimeFormat really switched from cmov to branch in a hot spot.
Fill results below:

name old time/op new time/op delta
BinaryTree17-6 4.42s ± 1% 4.44s ± 1% ~ (p=0.075 n=10+10)
Fannkuch11-6 4.23s ± 0% 4.18s ± 0% -1.16% (p=0.000 n=8+10)
FmtFprintfEmpty-6 67.5ns ± 2% 67.5ns ± 0% ~ (p=0.950 n=10+7)
FmtFprintfString-6 117ns ± 2% 119ns ± 1% +1.07% (p=0.045 n=9+10)
FmtFprintfInt-6 122ns ± 0% 123ns ± 2% ~ (p=0.825 n=8+10)
FmtFprintfIntInt-6 188ns ± 1% 187ns ± 1% -0.85% (p=0.001 n=10+10)
FmtFprintfPrefixedInt-6 223ns ± 1% 226ns ± 1% +1.40% (p=0.000 n=9+10)
FmtFprintfFloat-6 380ns ± 1% 379ns ± 0% ~ (p=0.350 n=9+7)
FmtManyArgs-6 784ns ± 0% 790ns ± 1% +0.81% (p=0.000 n=10+9)
GobDecode-6 10.7ms ± 1% 10.8ms ± 0% +0.68% (p=0.000 n=10+10)
GobEncode-6 8.95ms ± 0% 8.94ms ± 0% ~ (p=0.436 n=10+10)
Gzip-6 378ms ± 0% 378ms ± 0% ~ (p=0.696 n=8+10)
Gunzip-6 60.5ms ± 0% 60.9ms ± 0% +0.73% (p=0.000 n=8+10)
HTTPClientServer-6 109µs ± 3% 111µs ± 2% +2.53% (p=0.000 n=10+10)
JSONEncode-6 20.2ms ± 0% 20.2ms ± 0% ~ (p=0.382 n=8+8)
JSONDecode-6 85.9ms ± 1% 84.5ms ± 0% -1.59% (p=0.000 n=10+8)
Mandelbrot200-6 6.89ms ± 0% 6.85ms ± 1% -0.49% (p=0.000 n=9+10)
GoParse-6 5.49ms ± 0% 5.40ms ± 0% -1.63% (p=0.000 n=8+10)
RegexpMatchEasy0_32-6 126ns ± 1% 129ns ± 1% +2.14% (p=0.000 n=10+10)
RegexpMatchEasy0_1K-6 320ns ± 1% 317ns ± 2% ~ (p=0.089 n=10+10)
RegexpMatchEasy1_32-6 119ns ± 2% 121ns ± 4% ~ (p=0.591 n=10+10)
RegexpMatchEasy1_1K-6 544ns ± 1% 541ns ± 0% -0.67% (p=0.020 n=8+8)
RegexpMatchMedium_32-6 184ns ± 1% 184ns ± 1% ~ (p=0.360 n=10+10)
RegexpMatchMedium_1K-6 57.7µs ± 2% 58.3µs ± 1% +1.12% (p=0.022 n=10+10)
RegexpMatchHard_32-6 2.72µs ± 5% 2.70µs ± 0% ~ (p=0.166 n=10+8)
RegexpMatchHard_1K-6 80.2µs ± 0% 81.0µs ± 0% +1.01% (p=0.000 n=8+10)
Revcomp-6 607ms ± 0% 601ms ± 2% -1.00% (p=0.006 n=8+10)
Template-6 93.1ms ± 1% 92.6ms ± 0% -0.56% (p=0.000 n=9+9)
TimeParse-6 472ns ± 0% 470ns ± 0% -0.28% (p=0.001 n=9+9)
TimeFormat-6 546ns ± 0% 511ns ± 0% -6.41% (p=0.001 n=7+7)
[Geo mean] 76.4µs 76.3µs -0.12%

name old speed new speed delta
GobDecode-6 71.5MB/s ± 1% 71.1MB/s ± 0% -0.68% (p=0.000 n=10+10)
GobEncode-6 85.8MB/s ± 0% 85.8MB/s ± 0% ~ (p=0.425 n=10+10)
Gzip-6 51.3MB/s ± 0% 51.3MB/s ± 0% ~ (p=0.680 n=8+10)
Gunzip-6 321MB/s ± 0% 318MB/s ± 0% -0.73% (p=0.000 n=8+10)
JSONEncode-6 95.9MB/s ± 0% 96.0MB/s ± 0% ~ (p=0.367 n=8+8)
JSONDecode-6 22.6MB/s ± 1% 22.9MB/s ± 0% +1.62% (p=0.000 n=10+8)
GoParse-6 10.6MB/s ± 0% 10.7MB/s ± 0% +1.64% (p=0.000 n=8+10)
RegexpMatchEasy0_32-6 252MB/s ± 1% 247MB/s ± 1% -2.22% (p=0.000 n=10+10)
RegexpMatchEasy0_1K-6 3.19GB/s ± 1% 3.22GB/s ± 2% ~ (p=0.105 n=10+10)
RegexpMatchEasy1_32-6 267MB/s ± 2% 264MB/s ± 4% ~ (p=0.481 n=10+10)
RegexpMatchEasy1_1K-6 1.88GB/s ± 1% 1.89GB/s ± 0% +0.62% (p=0.038 n=8+8)
RegexpMatchMedium_32-6 5.41MB/s ± 2% 5.43MB/s ± 0% ~ (p=0.339 n=10+8)
RegexpMatchMedium_1K-6 17.8MB/s ± 1% 17.6MB/s ± 1% -1.12% (p=0.029 n=10+10)
RegexpMatchHard_32-6 11.8MB/s ± 5% 11.8MB/s ± 0% ~ (p=0.163 n=10+8)
RegexpMatchHard_1K-6 12.8MB/s ± 0% 12.6MB/s ± 0% -1.06% (p=0.000 n=7+10)
Revcomp-6 419MB/s ± 0% 423MB/s ± 2% +1.02% (p=0.006 n=8+10)
Template-6 20.9MB/s ± 0% 21.0MB/s ± 0% +0.53% (p=0.000 n=8+8)
[Geo mean] 77.0MB/s 77.0MB/s +0.05%

diff --git a/src/cmd/compile/internal/ssa/branchelim.go b/src/cmd/compile/internal/ssa/branchelim.go

Change-Id: Ibdffa9ea9b4c72668617ce3202ec4a83a1cd59be
Reviewed-on: https://go-review.googlesource.com/107936
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

25813f9f

cmd/vet/all: fix whitelist for CL 108557 · 01a74875

Russ Cox authored Apr 25, 2018

Change-Id: I831775db5de92d211495acc012fc4366c7c84851
Reviewed-on: https://go-review.googlesource.com/109335
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

01a74875

cmd/vet: use type information in isLocalType · 85146fab

Daniel Martí authored Feb 21, 2018

Now that vet always has type information, there's no reason to use
string handling on type names to gather information about them, such as
whether or not they are a local type.

The semantics remain the same - the only difference should be that the
implementation is less fragile and simpler.

Change-Id: I71386b4196922e4c9f2653d90abc382efbf01b3c
Reviewed-on: https://go-review.googlesource.com/95915
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

85146fab

internal/cpu: remove redundant build tag · 74f9432b

Martin Möhrmann authored Apr 24, 2018

The file name suffix arm64 already limits the file to be build only on arm64.

Change-Id: I33db713041b6dec9eb00889bac3b54c727e90743
Reviewed-on: https://go-review.googlesource.com/108986
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

74f9432b

sync: hide test of misuse of Cond from vet · eca7a134

Russ Cox authored Apr 20, 2018

The test wants to check that copies of Cond are detected at runtime.
Make a copy that isn't detected by vet at compile time.

Change-Id: I933ab1003585f75ba96723563107f1ba8126cb72
Reviewed-on: https://go-review.googlesource.com/108557Reviewed-by: Ian Lance Taylor <iant@golang.org>

eca7a134

doc: update "go get" HTTPS answer to mention .netrc · 09d36a81

Russ Cox authored Apr 18, 2018

The existing text makes it seem like there's no way
to use GitHub over HTTPS. There is. Explain that.

Also, the existing text suggests explicit checkout into $GOPATH,
which is not going to work in the new module world.
Drop that alternative.

Also, the existing text uses pushInsteadOf instead of insteadOf,
which would have the effect of being able to push to a private
repo but not clone it in the first place. That seems not helpful,
so suggest insteadOf instead.

Fixes #18927.

Change-Id: Ic358b66f88064b53067d174a2a1591ac8bf96c88
Reviewed-on: https://go-review.googlesource.com/107775
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

09d36a81

os: fix type check error in benchmark · e9bc0c5d

Russ Cox authored Apr 20, 2018

Previously, 's' was only written to, never read,
which is disallowed by the spec. cmd/compile
has a bug where it doesn't notice this when a
closure is involved, but go/types does notice,
which was making "go vet" fail.

This CL moves the variable into the closure
and also makes sure to use it.

Change-Id: I2d83fb6b5c1c9018df03533e966cbdf455f83bf9
Reviewed-on: https://go-review.googlesource.com/108556
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

e9bc0c5d

cmd/cgo: don't use absolute paths in the export header file · be012e1e

Ian Lance Taylor authored Apr 19, 2018

We were using absolute paths in the #line directives in the export
header file. This makes the header file change if you move GOPATH.
The absolute paths aren't helpful for the final user, which is some C
program elsewhere.

Fixes #24945

Change-Id: I2da32c9b477df578bd5087435a03fe97abe462e3
Reviewed-on: https://go-review.googlesource.com/108315
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

be012e1e

go/types: fix lhs/rhs mixup in docs · a5f19812

Matthew Dempsky authored Apr 24, 2018

Change-Id: Ifd51636c9254de51b8a21371d7507a9481bcca0a
Reviewed-on: https://go-review.googlesource.com/109142Reviewed-by: Robert Griesemer <gri@golang.org>

a5f19812

24 Apr, 2018 9 commits

cmd/compile: update SSA TODO file · ae26d57f

Keith Randall authored Apr 24, 2018

Get rid of a bunch of stuff we've already done.

Change-Id: Ibae4be7535ddb58590a072a2390c5f3e948c2fd7
Reviewed-on: https://go-review.googlesource.com/109136Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

ae26d57f

cmd/compile/internal/types: replace Type.Val with Type.Elem · 2083b5d6

Matthew Dempsky authored Apr 24, 2018

This reduces the API surface of Type slightly (for #25056), but also
makes it more consistent with the reflect and go/types APIs.

Passes toolstash-check.

Change-Id: Ief9a8eb461ae6e88895f347e2a1b7b8a62423222
Reviewed-on: https://go-review.googlesource.com/109138
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

2083b5d6

cmd/compile/internal/types: remove ElemType wrapper · e10ee798

Matthew Dempsky authored Apr 24, 2018

This was an artifact from when we had a separate ssa.Type interface to
break circular dependency between packages ssa and gc. It's no longer
needed now that package ssa directly uses package types.

Change-Id: I6a93e5d79082815f7f0eb89507381969cc6cb403
Reviewed-on: https://go-review.googlesource.com/109137
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

e10ee798

cmd/trace: distinguish task endTimestamp and lastTimestamp · 011f6c5f

Hana Kim authored Apr 24, 2018

A task may have other user annotation events after the task ends.
So far, task.lastTimestamp returned the task end event if the
event available. This change introduces task.endTimestamp for that
and makes task.lastTimestamp returns the "last" seen event's timestamp
if the task is ended.

If the task is not ended, both returns the last timestamp of the entire
trace assuming the task is still active.

This fixes the task-oriented trace view mode not to drop user
annotation instances when they appear outside a task's lifespan.
Adds a test.

Change-Id: Iba1062914f224edd521b9ee55c6cd5e180e55359
Reviewed-on: https://go-review.googlesource.com/109175Reviewed-by: Heschi Kreinick <heschi@google.com>

011f6c5f

internal/bytealg: optimize IndexString on arm64 · d4e936cf

erifan01 authored Apr 17, 2018

This CL adjusts the order of the branch instructions of the
code to make it easier for the LIKELY branch to happen.

Benchmarks:
name old time/op new time/op delta
pkg:strings goos:linux goarch:arm64
IndexHard2-8 2.17ms ± 1% 1.23ms ± 0% -43.34% (p=0.008 n=5+5)
CountHard2-8 2.13ms ± 1% 1.21ms ± 2% -43.31% (p=0.008 n=5+5)

pkg:bytes goos:linux goarch:arm64
IndexRune/4M-8 661µs ±22% 513µs ± 0% -22.32% (p=0.008 n=5+5)
IndexEasy/4M-8 672µs ±23% 513µs ± 0% -23.71% (p=0.016 n=5+4)

Change-Id: Ib96f095edf77747edc8a971e79f5c1428e5808ce
Reviewed-on: https://go-review.googlesource.com/109015Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

d4e936cf

cmd/link: fix TestRuntimeTypeAttr on ppc64,solaris · 5d4267e4

Heschi Kreinick authored Apr 23, 2018

For ppc64, skip -linkmode=external per
https://go-review.googlesource.com/c/go/+/106775#message-f95b9bd716e3d9ebb3f47a50492cde9f2972e859

For Solaris, apparently type.* isn't the same as runtime.types. I don't
know why, but runtime.types is what goes into moduledata, and so it's
definitely the more correct thing to use.

Fixes: #24983

Change-Id: I6b465ac7b8f91ce55a63acbd7fe76e4a2dbb6f22
Reviewed-on: https://go-review.googlesource.com/108955
Run-TryBot: Heschi Kreinick <heschi@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

5d4267e4

cmd/compile: improve regalloc live values debug printing · 3d6647d6

Josh Bleecher Snyder authored Apr 17, 2018

Before:

live values at end of each block
  b1: v3 v2 v7 avoid=0
  b2: v3 v13 avoid=81
  b3: v19[AX] v3 avoid=81
  b6: avoid=0
  b7: avoid=0
  b5: avoid=0
  b4: v3 v18 avoid=81

After:

live values at end of each block
  b1: v3 v2 v7
  b2: v3 v13 avoid=AX DI
  b3: v19[AX] v3 avoid=AX DI
  b6:
  b7:
  b5:
  b4: v3 v18 avoid=AX DI

Change-Id: Ibec5c76a16151832b8d49a21c640699fdc9a9d28
Reviewed-on: https://go-review.googlesource.com/109000
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

3d6647d6

runtime/trace: add simple benchmarks for user annotation · 3bf16444

Hana Kim authored Apr 24, 2018

Also, avoid Region creation when tracing is disabled.
Unfortunate side-effect of this change is that we no longer trace
pre-existing regions in tracing, but we can add the feature in
the future when we find it useful and justifiable. Until then,
let's avoid the overhead from this low-level api use as much as
possible.

goos: linux
goarch: amd64
pkg: runtime/trace

// Trace disabled
BenchmarkStartRegion-12 2000000000	         0.66 ns/op	       0 B/op	       0 allocs/op
BenchmarkNewTask-12    	30000000	        40.4 ns/op	      56 B/op	       2 allocs/op

// Trace enabled, -trace=/dev/null
BenchmarkStartRegion-12  5000000	       287 ns/op	      32 B/op	       1 allocs/op
BenchmarkNewTask-12    	 5000000	       283 ns/op	      56 B/op	       2 allocs/op

Also, skip other tests if tracing is already enabled.

Change-Id: Id3028d60b5642fcab4b09a74fd7d79361a3861e5
Reviewed-on: https://go-review.googlesource.com/109115Reviewed-by: Peter Weinberger <pjw@google.com>

3bf16444

runtime/trace: rename "Span" with "Region" · c2d10243

Hana Kim authored Apr 19, 2018

"Span" is a commonly used term in many distributed tracing systems
(Dapper, OpenCensus, OpenTracing, ...). They use it to refer to a
period of time, not necessarily tied into execution of underlying
processor, thread, or goroutine, unlike the "Span" of runtime/trace
package.

Since distributed tracing and go runtime execution tracing are
already similar enough to cause confusion, this CL attempts to avoid
using the same word if possible.

"Region" is being used in a certain tracing system to refer to a code
region which is pretty close to what runtime/trace.Span currently
refers to. So, replace that.
https://software.intel.com/en-us/itc-user-and-reference-guide-defining-and-recording-functions-or-regions

This CL also tweaks APIs a bit based on jbd and heschi's comments:

NewContext -> NewTask
and it now returns a Task object that exports End method.

StartSpan -> StartRegion
and it now returns a Region object that exports End method.

Also, changed WithSpan to WithRegion and it now takes func() with no
context. Another thought is to get rid of WithRegion. It is a nice
concept but in practice, it seems problematic (a lot of code churn,
and polluting stack trace). Already, the tracing concept is very low
level, and we hope this API to be used with great care.

Recommended usage will be
defer trace.StartRegion(ctx, "someRegion").End()

Left old APIs untouched in this CL. Once the usage of them are cleaned
up, they will be removed in a separate CL.

Change-Id: I73880635e437f3aad51314331a035dd1459b9f3a
Reviewed-on: https://go-review.googlesource.com/108296
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: JBD <jbd@google.com>

c2d10243