Currently Pool can cache up to 15 elements per P, and these elements are not accesible to other Ps.
If a Pool caches large objects, say 2MB, and GOMAXPROCS is set to a large value, say 32,
then the Pool can waste up to 960MB.
The new caching policy caches at most 1 per-P element, the rest is shared between Ps.

Get/Put performance is unchanged. Nested Get/Put performance is 57% worse.
However, overall scalability of nested Get/Put is significantly improved,
so the new policy starts winning under contention.

benchmark                     old ns/op     new ns/op     delta
BenchmarkPool                 27.4          26.7          -2.55%
BenchmarkPool-4               6.63          6.59          -0.60%
BenchmarkPool-16              1.98          1.87          -5.56%
BenchmarkPool-64              1.93          1.86          -3.63%
BenchmarkPoolOverlflow        3970          6235          +57.05%
BenchmarkPoolOverlflow-4      10935         1668          -84.75%
BenchmarkPoolOverlflow-16     13419         520           -96.12%
BenchmarkPoolOverlflow-64     10295         380           -96.31%

LGTM=rsc
R=rsc
CC=golang-codereviews, khr
https://golang.org/cl/86020043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/87140044

These are not ready and will not be in Go 1.3.

Fixes #6932.

LGTM=bradfitz
R=golang-codereviews, bradfitz, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87630043

We have never released cmd/prof and don't plan to.
Now that nm, addr2line, and objdump have been rewritten in Go,
cmd/prof is the only thing keeping us from deleting libmach.

Delete cmd/prof, and then since nothing is using libmach, delete libmach.

13,000 lines of C deleted.

LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87020044

Fixes #6981

LGTM=rsc
R=golang-codereviews, nightlyone
CC=adg, dsymonds, golang-codereviews, rsc
https://golang.org/cl/85560045

Update cmd/dist not to build the C version.
Update cmd/go to install the Go version to the tool directory.

Update #7452

This is the basic logic needed for objdump, and it works well enough
to support the pprof list and weblist commands. A real disassembler
needs to be added in order to support the pprof disasm command
and the per-line assembly displays in weblist. That's still to come.

Probably objdump will move to go.tools when the disassembler
is added, but it can stay here for now.

LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87580043

Broke other things - see issue 7522.

Fixes #7522.
Reopens issue 7363.

««« original CL description
cmd/gc: make embedded, unexported fields read-only.

Fixes #7363.

LGTM=gri
R=gri, rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/66510044
»»»

LGTM=r, mpvl
R=golang-codereviews, r
CC=golang-codereviews, iant, mpvl
https://golang.org/cl/85580046

It looks like maybe on slower builders 4 seconds is not enough.
Trying to get rid of the flaky failures.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/86870044

LGTM=alex.brainman
R=alex.brainman
CC=golang-codereviews
https://golang.org/cl/87250043

R=adg

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/86930043

What was happening on Issue 7010 was handler intentionally took 30
milliseconds and the proxy's client timeout was 35 milliseconds. Then it
slammed the proxy with a bunch of requests.

Sometimes the server would be too slow to respond in its 5 millisecond
window and the client code would cancel the request, force-closing the
persistConn.  If this came at the right time, the server's reply was
already in flight, and one of the goroutines would report:

Unsolicited response received on idle HTTP channel starting with "H"; err=<nil>

... rightfully scaring the user.

But the error was already handled and returned to the user, and this
connection knows it's been shut down. So look at the closed flag after
acquiring the same mutex guarding another field we were checking, and
don't complain if it's a known shutdown.

Also move closed down below the mutex which guards it.

Fixes #7010

LGTM=dsymonds
R=golang-codereviews, dsymonds
CC=adg, golang-codereviews, rsc
https://golang.org/cl/86740044

Fixes #7129

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/86470044

Fixes #7742

LGTM=dave, rsc
R=rsc, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/85580047

The test fails now with -race, so it's disabled.
The intention is that the fix for issue 7264
will also modify this test the same way and enable it.
Reporduce with 'go test -race -issue7264 -cpu=4'.
Update #7264

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/86770043

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/84650047

Add test for multipart form requests with an invalid content-type to ensure
ErrNotMultipart is returned.

Change ParseMultipartForm to return ErrNotMultipart when it is returned by multipartReader.

Modify test for empty multipart request handling to use POST so that the body is checked.

Fixes #6334.

This is the first changeset working on multipart request handling. Further changesets
could add more tests and clean up the TODO.

LGTM=bradfitz
R=golang-codereviews, gobot, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/44040043

I was implementing rules from RFC 2616. The rules are apparently useless,
ambiguous, and too strict for common software on the Internet. (e.g. curl)

Add more tests, including a test of a chunked request.

Fixes #7625

LGTM=dsymonds
R=golang-codereviews, dsymonds
CC=adg, golang-codereviews, rsc
https://golang.org/cl/84480045

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/86420046

Also: Simplify ReadSlice implementation and
ensure that it doesn't call fill() with a full
buffer (this caused a failure in net/textproto
TestLargeReadMIMEHeader because fill() wasn't able
to read more data).

Fixes #7745.

LGTM=bradfitz
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/86590043

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/86060044

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/86600045

To create a valid JSON string, "%s" is not enough.
Fixes #7761.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/86730043

It runs too long in -short mode.

Disable the one in init, because it doesn't respect -short.

Make the part that claims to test execution in a finalizer
actually execute the test in the finalizer.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=aram.h, golang-codereviews, iant, khr
https://golang.org/cl/86550045

The Go HTTP server doesn't use Response.Write, but others do,
so make it correct. Add a bunch more tests.

This bug is almost a year old. :/

Fixes #5381

LGTM=adg
R=golang-codereviews, adg
CC=dsymonds, golang-codereviews, rsc
https://golang.org/cl/85740046

Go's had pretty decent HTTP Trailer support for a long time, but
the docs have been largely non-existent. Fix that.

In the process, re-learn the Trailer code, clean some stuff
up, add some error checks, remove some TODOs, fix a minor bug
or two, and add tests.

LGTM=adg
R=golang-codereviews, adg
CC=dsymonds, golang-codereviews, rsc
https://golang.org/cl/86660043

Keep those builders busy.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/85710046

Tests for the race detector to catch anybody
trying to mutate Reader in ReadAt.

LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/86700043

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/86580043

Fixes #7750.

LGTM=bradfitz
R=golang-codereviews, ibilicc, bradfitz
CC=golang-codereviews
https://golang.org/cl/84850043

TBR=0intro
CC=golang-codereviews
https://golang.org/cl/86620043

LGTM=iant
R=remyoudompheng, iant
CC=golang-codereviews
https://golang.org/cl/86270043

There is a race condition that causes spurious wakeup from Wait
in the following case:

 G1: decrement wg.counter, observe the counter is now 0
     (should unblock goroutines queued *at this moment*)
 G2: increment wg.counter
 G2: call Wait() to add itself to the wait queue
 G1: acquire wg.m, unblock all waiting goroutines

In the last step G2 is spuriously woken up by G1.
Fixes #7734.

LGTM=rsc, dvyukov
R=dvyukov, 0xjnml, rsc
CC=golang-codereviews
https://golang.org/cl/85580043

In a typical HTTP request, the client writes the request, and
then the server replies. Go's HTTP client code (Transport) has
two goroutines per connection: one writing, and one reading. A
third goroutine (the one initiating the HTTP request)
coordinates with those two.

Because most HTTP requests are done when the server replies,
the Go code has always handled connection reuse purely in the
readLoop goroutine.

But if a client is writing a large request and the server
replies before it's consumed the entire request (e.g. it
replied with a 403 Forbidden and had no use for the body), it
was possible for Go to re-select that connection for a
subsequent request before we were done writing the first. That
wasn't actually a data race; the second HTTP request would
just get enqueued to write its request on the writeLoop. But
because the previous writeLoop didn't finish writing (and
might not ever), that connection is in a weird state. We
really just don't want to get into a state where we're
re-using a connection when the server spoke out of turn.

This CL changes the readLoop goroutine to verify that the
writeLoop finished before returning the connection.

In the process, it also fixes a potential goroutine leak where
a connection could close but the recycling logic could be
blocked forever waiting for the client to read to EOF or
error. Now it also selects on the persistConn's close channel,
and the closer of that is no longer the readLoop (which was
dead locking in some cases before). It's now closed at the
same place the underlying net.Conn is closed. This likely fixes
or helps Issue 7620.

Also addressed some small cosmetic things in the process.

Update #7620
Fixes #7569

LGTM=adg
R=golang-codereviews, adg
CC=dsymonds, golang-codereviews, rsc
https://golang.org/cl/86290043

We originally decided to skip this test in short mode
to prevent the parallel runtime test to timeout on the
Plan 9 builder. This should no longer be required since
the issue was fixed in CL 86210043.

LGTM=dave, bradfitz
R=dvyukov, dave, bradfitz
CC=golang-codereviews, rsc
https://golang.org/cl/84790044

If you pass ns = 100,000 to this function, timediv will
return ms = 0. tsemacquire in /sys/src/9/port/sysproc.c
will return immediately when ms == 0 and the semaphore
cannot be acquired immediately - it doesn't sleep - so
notetsleep will spin, chewing cpu and repeatedly reading
the time, until the 100us have passed.

Thanks to the time reads it won't take too many iterations,
but whatever we are waiting for does not get a chance to
run. Eventually the notetsleep spin loop returns and we
end up in the stoptheworld spin loop - actually a sleep
loop but we're not doing a good job of sleeping.

After 100ms or so of this, the kernel says enough and
schedules a different thread. That thread manages to do
whatever we're waiting for, and the spinning in the other
thread stops. If tsemacquire had actually slept, this
would have happened much quicker.

Many thanks to Russ Cox for help debugging.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/86210043

All that's left is net/http and the stuff I need help describing: FreeBSD and Windows.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/86320043

even when there are no *_test.go files present.
rsc suggested this change

Fixes #7108

LGTM=r, adg
R=golang-codereviews, r, adg
CC=golang-codereviews
https://golang.org/cl/84300043

The buffer length should be the size in bytes
instead of the number of structs.

Fixes #6588.

LGTM=mikioh.mikioh
R=golang-codereviews, mikioh.mikioh, adg
CC=golang-codereviews
https://golang.org/cl/84830043

Generated by addca.

R=gobot
CC=golang-codereviews
https://golang.org/cl/85550044

bufio: undo incorrect bug fix

««« original CL description
bufio: fix potential endless loop in ReadByte

Fixes #7745.

LGTM=bradfitz, r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/86220044
»»»

LGTM=adg
R=r, adg
CC=golang-codereviews
https://golang.org/cl/85550045