R=gri
CC=golang-codereviews
https://golang.org/cl/104340043

This CL re-applies the tests added in CL 101330053 and subsequently rolled back in CL 102610043.

The original author of this change was Rui Ueyama <ruiu@google.com>

LGTM=r, ruiu
R=ruiu, r
CC=golang-codereviews
https://golang.org/cl/109170043

The number of estimated iterations required to reach the benchtime is multiplied by a safety margin (to avoid falling just short) and then rounded up to a readable number. With an accurate estimate, in the worse case, the resulting number of iterations could be 3.75x more than necessary: 1.5x for safety * 2.5x to round up (e.g. from 2eX+1 to 5eX).

This CL reduces the safety margin to 1.2x. Experimentation showed a diminishing margin of return past 1.2x, although the average case continued to show improvements down to 1.05x.

This CL also reduces the maximum round-up multiplier from 2.5x (from 2eX+1 to 5eX) to 2x, by allowing the number of iterations to be of the form 3eX.

Both changes improve benchmark wall clock times, and the effects are cumulative.

From 1.5x to 1.2x safety margin:

package		old s	new s	delta
bytes		163	125	-23%
encoding/json	27	21	-22%
net/http	42	36	-14%
runtime		463	418	-10%
strings		82	65	-21%

Allowing 3eX iterations:

package		old s	new s	delta
bytes		163	134	-18%
encoding/json	27	23	-15%
net/http	42	36	-14%
runtime		463	422	-9%
strings		82	72	-12%

Combined:

package		old s	new s	delta
bytes		163	112	-31%
encoding/json	27	20	-26%
net/http	42	30	-29%
runtime		463	346	-25%
strings		82	60	-27%

LGTM=crawshaw, r, rsc
R=golang-codereviews, crawshaw, r, rsc
CC=golang-codereviews
https://golang.org/cl/105990045

The previous call to parseRange already checks whether
all the ranges start before the end of file.

LGTM=robert.hencke, bradfitz
R=golang-codereviews, robert.hencke, gobot, bradfitz
CC=golang-codereviews
https://golang.org/cl/91880044

Updates z-files from 10.7 kernel-based to 10.9 kernel-based.

LGTM=iant
R=golang-codereviews, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/102610045

LGTM=iant
R=ruiu, iant
CC=golang-codereviews
https://golang.org/cl/107320044

Update #1435

This proposal disables Setuid and Setgid on all linux platforms.

Issue 1435 has been open for a long time, and it is unlikely to be addressed soon so an argument was made by a commenter

https://code.google.com/p/go/issues/detail?id=1435#c45

That these functions should made to fail rather than succeed in their broken state.

LGTM=ruiu, iant
R=iant, ruiu
CC=golang-codereviews
https://golang.org/cl/106170043

Update #8266

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/104290043

MOV with SSE registers seems faster than REP MOVSQ if the
size being copied is less than about 2K. Previously we
didn't use MOV if the memory region is larger than 256
byte. This patch improves the performance of 257 ~ 2048
byte non-overlapping copy by using MOV.

Here is the benchmark result on Intel Xeon 3.5GHz (Nehalem).

benchmark               old ns/op    new ns/op    delta
BenchmarkMemmove16              4            4   +0.42%
BenchmarkMemmove32              5            5   -0.20%
BenchmarkMemmove64              6            6   -0.81%
BenchmarkMemmove128             7            7   -0.82%
BenchmarkMemmove256            10           10   +1.92%
BenchmarkMemmove512            29           16  -44.90%
BenchmarkMemmove1024           37           25  -31.55%
BenchmarkMemmove2048           55           44  -19.46%
BenchmarkMemmove4096           92           91   -0.76%

benchmark                old MB/s     new MB/s  speedup
BenchmarkMemmove16        3370.61      3356.88    1.00x
BenchmarkMemmove32        6368.68      6386.99    1.00x
BenchmarkMemmove64       10367.37     10462.62    1.01x
BenchmarkMemmove128      17551.16     17713.48    1.01x
BenchmarkMemmove256      24692.81     24142.99    0.98x
BenchmarkMemmove512      17428.70     31687.72    1.82x
BenchmarkMemmove1024     27401.82     40009.45    1.46x
BenchmarkMemmove2048     36884.86     45766.98    1.24x
BenchmarkMemmove4096     44295.91     44627.86    1.01x

LGTM=khr
R=golang-codereviews, gobot, khr
CC=golang-codereviews
https://golang.org/cl/90500043

Also exposes common socket option functions on Solaris.

Update #7174
Update #7175

LGTM=aram
R=golang-codereviews, aram
CC=golang-codereviews
https://golang.org/cl/107280044

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/110020050

paeth(0, x, 0) == x for any uint8 value.

LGTM=nigeltao
R=golang-codereviews, bradfitz, nigeltao
CC=golang-codereviews
https://golang.org/cl/105290049

sync.Pool is not supposed to be used everywhere, but is
a last resort.

««« original CL description
strings: use sync.Pool to cache buffer

benchmark                         old ns/op    new ns/op    delta
BenchmarkByteReplacerWriteString       3596         3094  -13.96%

benchmark                        old allocs   new allocs    delta
BenchmarkByteReplacerWriteString          1            0  -100.00%

LGTM=dvyukov
R=bradfitz, dave, dvyukov
CC=golang-codereviews
https://golang.org/cl/101330053
»»»

LGTM=dave
R=r, dave
CC=golang-codereviews
https://golang.org/cl/102610043

Fixes #8074.

The issue was not reproduceable by revision

go version devel +e0ad7e329637 Thu Jun 19 22:19:56 2014 -0700 linux/arm

But include the original test case in case the issue reopens itself.

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/107290043

benchmark                         old ns/op    new ns/op    delta
BenchmarkByteReplacerWriteString       3596         3094  -13.96%

benchmark                        old allocs   new allocs    delta
BenchmarkByteReplacerWriteString          1            0  -100.00%

LGTM=dvyukov
R=bradfitz, dave, dvyukov
CC=golang-codereviews
https://golang.org/cl/101330053

R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/103520044

LGTM=ruiu
R=golang-codereviews, ruiu
CC=golang-codereviews
https://golang.org/cl/109100046

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/102580043

All tests pass except one test in regexp package.

LGTM=iant
R=golang-codereviews, iant, dave
CC=golang-codereviews
https://golang.org/cl/107270043

It was built on an old, bogus revision.

LGTM=minux
TBR=iant
R=iant, minux
CC=golang-codereviews
https://golang.org/cl/101370052

This requires minimal changes to the runtime hooks. In particular,
synchronization events must be done only on valid addresses now,
so I've added the additional checks to race.c.

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/101000046

benchmark                         old ns/op    new ns/op    delta
BenchmarkByteReplacerWriteString       7359         3661  -50.25%

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/102550043

Fixes #7858.

LGTM=ruiu
R=ruiu
CC=golang-codereviews
https://golang.org/cl/92720045

Single-case select with a non-nil channel is pointless.

LGTM=mikioh.mikioh
R=mikioh.mikioh
CC=golang-codereviews
https://golang.org/cl/103920044

Afterprologue check was required when did not know
about return arguments of functions and/or they were not zeroed.
Now 100% precision is required for stacks due to stack copying,
so it must work w/o afterprologue one way or another.
I can limit this change for 1.3 to merely adding a TODO,
but this check is super confusing so I don't want this knowledge to get lost.

LGTM=rsc
R=golang-codereviews, gobot, rsc, khr
CC=golang-codereviews, khr, rsc
https://golang.org/cl/96580045

LGTM=dave
R=golang-codereviews, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/109090048

Avoid unnecessary bitwise-OR operations.

benchmark                      old MB/s     new MB/s  speedup
BenchmarkEncodeToStringBase64  179.02       205.74    1.15x
BenchmarkEncodeToStringBase32  155.86       167.82    1.08x

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/109090043

Use WriteString instead of allocating a byte slice as a
buffer. This was a TODO.

benchmark               old ns/op    new ns/op    delta
BenchmarkWriteString        40139        19991  -50.20%

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/107190044

Fixes #8201.

LGTM=nigeltao
R=nigeltao
CC=golang-codereviews
https://golang.org/cl/105990046

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/102830043

requires a decoder to do its own byte buffering instead of using
bufio.Reader, due to byte stuffing.

benchmark                      old MB/s     new MB/s     speedup
BenchmarkDecodeBaseline        33.40        50.65        1.52x
BenchmarkDecodeProgressive     24.34        31.92        1.31x

On 6g, unsafe.Sizeof(huffman{}) falls from 4872 to 964 bytes, and
the decoder struct contains 8 of those.

LGTM=r
R=r, nightlyone
CC=bradfitz, couchmoney, golang-codereviews, raph
https://golang.org/cl/109050045

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://golang.org/cl/107200043

This is a clone of 101370043, which I accidentally applied to the
release branch first.
No big deal, it needed to be applied there anyway.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/108090043

Fixes #7694.

LGTM=nigeltao, rsc, r
R=golang-codereviews, nigeltao, rsc, r
CC=golang-codereviews
https://golang.org/cl/109000049

Storing temporary values to a slice is slower than storing
them to local variables of type byte.

benchmark                         old MB/s     new MB/s  speedup
BenchmarkEncodeToStringBase32       102.21       156.66    1.53x
BenchmarkEncodeToStringBase64       124.25       177.91    1.43x

LGTM=crawshaw
R=golang-codereviews, crawshaw, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/109820045

Fixes #8175.

LGTM=r
R=golang-codereviews, r, gobot
CC=golang-codereviews
https://golang.org/cl/103320043

Just to be more thorough.
No need to push this to 1.3; it's just a test change that
worked without any changes to the code being tested.

LGTM=crawshaw
R=golang-codereviews, crawshaw
CC=golang-codereviews
https://golang.org/cl/109080045

LGTM=bradfitz
R=adg, rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/102470045

genericReplacer.lookup is called for each byte of an input
string. In many (most?) cases, lookup will fail for the first
byte, and it will return immediately. Adding a fast path for
that case seems worth it.

Benchmark on my Xeon 3.5GHz Linux box:

benchmark                        old ns/op    new ns/op    delta
BenchmarkGenericNoMatch               2691          774  -71.24%
BenchmarkGenericMatch1                7920         8151   +2.92%
BenchmarkGenericMatch2               52336        39927  -23.71%
BenchmarkSingleMaxSkipping            1575         1575   +0.00%
BenchmarkSingleLongSuffixFail         1429         1429   +0.00%
BenchmarkSingleMatch                 56228        55444   -1.39%
BenchmarkByteByteNoMatch               568          568   +0.00%
BenchmarkByteByteMatch                 977          972   -0.51%
BenchmarkByteStringMatch              1669         1687   +1.08%
BenchmarkHTMLEscapeNew                 422          422   +0.00%
BenchmarkHTMLEscapeOld                 692          670   -3.18%
BenchmarkByteByteReplaces             8492         8474   -0.21%
BenchmarkByteByteMap                  2817         2808   -0.32%

LGTM=rsc
R=golang-codereviews, bradfitz, dave, rsc
CC=golang-codereviews
https://golang.org/cl/79200044

Make assembly govet-clean.
Clean up fixes for CL 93380044.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/107160047