Lighten contention without preventing further improvements on pollservers.
Connections are spread over Min(GOMAXPROCS, NumCPU, 8) pollserver instances.

Median of 10 runs, 4 cores @ 3.4GHz, amd/linux-3.2:

BenchmarkTCPOneShot                171917 ns/op   175194 ns/op      1.91%
BenchmarkTCPOneShot-2              101413 ns/op   109462 ns/op      7.94%
BenchmarkTCPOneShot-4               91796 ns/op    35712 ns/op    -61.10%
BenchmarkTCPOneShot-6               90938 ns/op    30607 ns/op    -66.34%
BenchmarkTCPOneShot-8               90374 ns/op    29150 ns/op    -67.75%
BenchmarkTCPOneShot-16             101089 ns/op   111526 ns/op     10.32%

BenchmarkTCPOneShotTimeout         174986 ns/op   178606 ns/op      2.07%
BenchmarkTCPOneShotTimeout-2       101585 ns/op   110678 ns/op      8.95%
BenchmarkTCPOneShotTimeout-4        91547 ns/op    35931 ns/op    -60.75%
BenchmarkTCPOneShotTimeout-6        91496 ns/op    31019 ns/op    -66.10%
BenchmarkTCPOneShotTimeout-8        90670 ns/op    29531 ns/op    -67.43%
BenchmarkTCPOneShotTimeout-16      101013 ns/op   106026 ns/op      4.96%

BenchmarkTCPPersistent              51731 ns/op    53324 ns/op      3.08%
BenchmarkTCPPersistent-2            32888 ns/op    30678 ns/op     -6.72%
BenchmarkTCPPersistent-4            25751 ns/op    15595 ns/op    -39.44%
BenchmarkTCPPersistent-6            26737 ns/op     9805 ns/op    -63.33%
BenchmarkTCPPersistent-8            26850 ns/op     9730 ns/op    -63.76%
BenchmarkTCPPersistent-16          104449 ns/op   102838 ns/op     -1.54%

BenchmarkTCPPersistentTimeout       51806 ns/op    53281 ns/op      2.85%
BenchmarkTCPPersistentTimeout-2     32956 ns/op    30895 ns/op     -6.25%
BenchmarkTCPPersistentTimeout-4     25994 ns/op    18111 ns/op    -30.33%
BenchmarkTCPPersistentTimeout-6     26679 ns/op     9846 ns/op    -63.09%
BenchmarkTCPPersistentTimeout-8     26810 ns/op     9727 ns/op    -63.72%
BenchmarkTCPPersistentTimeout-16   101652 ns/op   104410 ns/op      2.71%

R=rsc, dvyukov, dave, mikioh.mikioh, bradfitz, remyoudompheng
CC=golang-dev
https://golang.org/cl/6496054

In two cases, registers were allocated too early resulting
in exhausting of available registers when nesting these
operations.

The case of method calls was due to missing cases in igen,
which only makes calls but doesn't allocate a register for
the result.

The case of 8-bit multiplication was due to a wrong order
in register allocation when Ullman numbers were bigger on the
RHS.

Fixes #3907.
Fixes #4156.

R=rsc
CC=golang-dev, remy
https://golang.org/cl/6560054

Low hanging fruit optimization. Will remove an expensive copy if the range variable is an array.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6564052

R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/6571056

Link to the "installing from source" docs instead of the "installing" docs.

Remind would-be hacker to switch to the default branch from the release branch.

R=rsc
CC=golang-dev
https://golang.org/cl/6559043

This CL requires CL 5970055.

benchmark           old ns/op    new ns/op    delta
BenchmarkEncrypt          161           23  -85.71%
BenchmarkDecrypt          158           24  -84.24%
BenchmarkExpand           526           62  -88.21%

benchmark            old MB/s     new MB/s  speedup
BenchmarkEncrypt        99.32       696.19    7.01x
BenchmarkDecrypt       100.93       641.56    6.36x

R=golang-dev, bradfitz, dave, rsc
CC=golang-dev
https://golang.org/cl/6549055

This CL adds support for the these 7 new instructions to 6a/6l in
preparation of the upcoming CL for AES-NI accelerated crypto/aes:
AESENC, AESENCLAST, AESDEC, AESDECLAST, AESIMC, AESKEYGENASSIST,
and PSHUFD.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5970055

Fixes #4121.

R=golang-dev, minux.ma, dave, r
CC=golang-dev
https://golang.org/cl/6555049

Also: Adjust prose in Conversions section
to be consistent.

This is a backward-compatible syntax change.
For a discussion see issue 2568.

Fixes #2568.
Fixes #4123.

R=golang-dev, r, iant, rsc
CC=golang-dev
https://golang.org/cl/6572049

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6570054

        Fixes #4063.

R=alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/6543066

Do not check compiler/linker timestamps for packages that are in the
$GOROOT. Avoids trying to rebuild non-writable standard packages when
timestamps have not been retained on the Go binaries.

Fixes #4106.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6533053

The previous version was created by an idiot. This time, Rog Peppe
wrote the text. Thanks, Rog.
(== doesn't work on slices in general, so it makes no sense to
talk about in the context of DeepEqual.)

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6566054

R=golang-dev, lucio.dere, fshahriar
CC=golang-dev
https://golang.org/cl/6562046

Update #4133.
Added a sentence of documentation to call out the behavior.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6572051

Mostly minor changes to match the new
definitions in types.go and const.go.

R=rsc, r
CC=golang-dev
https://golang.org/cl/6506101

This code relies on some functions that are not yet in staging,
but it get's harder to keep all this in sync in a piece-meal
fashion.

R=rsc
CC=golang-dev
https://golang.org/cl/6492124

More pieces of the typechecker code:

- Operands are temporary objects representing an expressions's
type and value (for constants). An operand is the equivalent of
an "attribute" in attribute grammars except that it's not stored
but only passed around during type checking.

- Constant operations are implemented in const.go. Constants are
represented as bool (booleans), int64 and *big.Int (integers),
*big.Rat (floats), complex (complex numbers), and string (strings).

- Error reporting is consolidated in errors.go. Only the first
dozen of lines is new code, the rest of the file contains the
exprString and typeString functions formerly in two separate
files (which have been removed).

This is a replacement CL for 6492101 (which was created without
proper use of hg).

R=rsc, r
CC=golang-dev
https://golang.org/cl/6500114

Fixes #4152.

R=bradfitz
CC=golang-dev
https://golang.org/cl/6570045

Fixes #4147.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6569050

file        old_size     new_size    base@c1ce95068533
bin/go      14717392     6287824     5918236

this huge size difference is due to GC data for runtime.mheap
(NOPTR dataflag is not obeyed).

R=rsc, dave
CC=golang-dev
https://golang.org/cl/6547051

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/6564046

Remove VERSION, which was forcing version to 'devel'.

Old:
$ go version
go version devel

New:
$ go version
go version devel +0a3866d6cc6b Mon Sep 24 20:08:05 2012 -0400

The date and time (and time zone) is that of the most recent commit,
not the time of the build itself. With some effort we could normalize
the zone, but I don't think it's worth the effort (more C coding,
since Mercurial is unhelpful).

R=r, dsymonds
CC=golang-dev
https://golang.org/cl/6569049

The assembly offsets were converted mechanically using
code.google.com/p/rsc/cmd/asmlint. The instruction
changes were done by hand.

Fixes #2188.

R=iant, r, bradfitz, remyoudompheng
CC=golang-dev
https://golang.org/cl/6550058

R=rsc
CC=golang-dev
https://golang.org/cl/6554060

Fixes #1765.

R=iant, r, daniel.morsing, minux.ma, bradfitz, rogpeppe, remyoudompheng
CC=golang-dev
https://golang.org/cl/6554067

Both methods allow to access the IP ancillary data through
socket control messages.

This CL is required for CL 6482044; go.net/ipv4: new package.

R=rsc, r, dave
CC=golang-dev
https://golang.org/cl/6426047

R=golang-dev, rsc, dave
CC=golang-dev
https://golang.org/cl/6569044

Apart from reducing the number of LEAL/LEAQ instructions by about
30%, it gives 8g easier registerization in several cases,
for example in strconv. Performance with 6g is not affected.

Before (386):
src/pkg/strconv/decimal.go:22   TEXT  (*decimal).String+0(SB),$240-12
src/pkg/strconv/extfloat.go:540 TEXT  (*extFloat).ShortestDecimal+0(SB),$584-20

After (386):
src/pkg/strconv/decimal.go:22   TEXT  (*decimal).String+0(SB),$196-12
src/pkg/strconv/extfloat.go:540 TEXT  (*extFloat).ShortestDecimal+0(SB),$420-20

Benchmarks with GOARCH=386 (on a Core 2).

benchmark                 old ns/op    new ns/op    delta
BenchmarkBinaryTree17    7110191000   7079644000   -0.43%
BenchmarkFannkuch11      7769274000   7766514000   -0.04%
BenchmarkGobDecode         33454820     34755400   +3.89%
BenchmarkGobEncode         11675710     11007050   -5.73%
BenchmarkGzip            2013519000   1593855000  -20.84%
BenchmarkGunzip           253368200    242667600   -4.22%
BenchmarkJSONEncode       152443900    120763400  -20.78%
BenchmarkJSONDecode       304112800    247461800  -18.63%
BenchmarkMandelbrot200     29245520     29240490   -0.02%
BenchmarkParse              8484105      8088660   -4.66%
BenchmarkRevcomp         2695688000   2841263000   +5.40%
BenchmarkTemplate         363759800    277271200  -23.78%

benchmark                       old ns/op    new ns/op    delta
BenchmarkAtof64Decimal                127          129   +1.57%
BenchmarkAtof64Float                  166          164   -1.20%
BenchmarkAtof64FloatExp               308          300   -2.60%
BenchmarkAtof64Big                    584          571   -2.23%
BenchmarkAppendFloatDecimal           440          430   -2.27%
BenchmarkAppendFloat                  995          776  -22.01%
BenchmarkAppendFloatExp               897          746  -16.83%
BenchmarkAppendFloatNegExp            900          752  -16.44%
BenchmarkAppendFloatBig              1528         1228  -19.63%
BenchmarkAppendFloat32Integer         443          453   +2.26%
BenchmarkAppendFloat32ExactFraction   812          661  -18.60%
BenchmarkAppendFloat32Point          1002          773  -22.85%
BenchmarkAppendFloat32Exp             858          725  -15.50%
BenchmarkAppendFloat32NegExp          848          728  -14.15%
BenchmarkAppendFloat64Fixed1          447          431   -3.58%
BenchmarkAppendFloat64Fixed2          480          462   -3.75%
BenchmarkAppendFloat64Fixed3          461          457   -0.87%
BenchmarkAppendFloat64Fixed4          509          484   -4.91%

Update #1914.

R=rsc, nigeltao
CC=golang-dev, remy
https://golang.org/cl/6494107

Session resumption saves a round trip and removes the need to perform
the public-key operations of a TLS handshake when both the client and
server support it (which is true of Firefox and Chrome, at least).

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6555051

Fixes #4080.

R=rsc, adg
CC=golang-dev
https://golang.org/cl/6553068

Was not handling &x.y[0] and &x.y.z correctly where
y is an array or struct-valued field (not a pointer).

R=ken2
CC=golang-dev
https://golang.org/cl/6551059

Update #3953.

R=bradfitz, campoy
CC=golang-dev
https://golang.org/cl/6543068

Comparisons used to create temporaries for arguments
even if they were already variables or addressable.
Removing the extra ones reduces pressure on regopt.

benchmark                 old ns/op    new ns/op    delta
BenchmarkGobDecode         50787620     49908980   -1.73%
BenchmarkGobEncode         19870190     19473030   -2.00%
BenchmarkGzip            3214321000   3067929000   -4.55%
BenchmarkGunzip           496792800    465828600   -6.23%
BenchmarkJSONEncode       232524800    263864400  +13.48%
BenchmarkJSONDecode       622038400    506600600  -18.56%
BenchmarkMandelbrot200     23937310     45913060  +91.81%
BenchmarkParse             14364450     13997010   -2.56%
BenchmarkRevcomp         6919028000   6480009000   -6.35%
BenchmarkTemplate         594458800    539528200   -9.24%

benchmark                  old MB/s     new MB/s  speedup
BenchmarkGobDecode            15.11        15.38    1.02x
BenchmarkGobEncode            38.63        39.42    1.02x
BenchmarkGzip                  6.04         6.33    1.05x
BenchmarkGunzip               39.06        41.66    1.07x
BenchmarkJSONEncode            8.35         7.35    0.88x
BenchmarkJSONDecode            3.12         3.83    1.23x
BenchmarkParse                 4.03         4.14    1.03x
BenchmarkRevcomp              36.73        39.22    1.07x
BenchmarkTemplate              3.26         3.60    1.10x

R=mtj, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6547064

R=rsc, nigeltao, dave, bradfitz, r, rogpeppe
CC=golang-dev
https://golang.org/cl/6497084

This CL makes the compiler understand that the type of
the len or cap of a map, slice, or string is 'int', not 'int32'.
It does not change the meaning of int, but it should make
the eventual change of the meaning of int in 6g a bit smoother.

Update #2188.

R=ken, dave, remyoudompheng
CC=golang-dev
https://golang.org/cl/6542059

Use explicit IntSize constant instead of 4.

This CL does not change the meaning of int, but it should make
the eventual change of the meaning of int on amd64 a bit
smoother.

Update #2188.

R=ken, dave
CC=golang-dev
https://golang.org/cl/6554076

This CL makes the size of an int controlled by a variable
in cgo instead of hard-coding 4 (or 32 bits) in various places.

Update #2188.

R=iant, r, dave
CC=golang-dev
https://golang.org/cl/6548061

In a few places, the existing cgo tests assume that a
Go int is the same as a C int. Making int 64 bits wide
on 64-bit platforms violates this assumption.
Change that code to assume that Go int32 and C int
are the same instead. That's still not great, but it's better,
and I am unaware of any systems we run on where it is not true.

Update #2188.

R=iant, r
CC=golang-dev
https://golang.org/cl/6552064

This CL makes the runtime understand that the type of
the len or cap of a map, slice, or string is 'int', not 'int32',
and it is also careful to distinguish between function arguments
and results of type 'int' vs type 'int32'.

In the runtime, the new typedefs 'intgo' and 'uintgo' refer
to Go int and uint. The C types int and uint continue to be
unavailable (cause intentional compile errors).

This CL does not change the meaning of int, but it should make
the eventual change of the meaning of int on amd64 a bit
smoother.

Update #2188.

R=iant, r, dave, remyoudompheng
CC=golang-dev
https://golang.org/cl/6551067