Commit graph

37991 commits

Author SHA1 Message Date
Keith Randall 9a8372f8bd cmd/compile,runtime: remove ambiguously live logic
The previous CL introduced stack objects. This CL removes the old
ambiguously live liveness analysis. After this CL we're relying
on stack objects exclusively.

Update a bunch of liveness tests to reflect the new world.

Fixes #22350

Change-Id: I739b26e015882231011ce6bc1a7f426049e59f31
Reviewed-on: https://go-review.googlesource.com/c/134156
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-10-03 19:54:16 +00:00
Keith Randall cbafcc55e8 cmd/compile,runtime: implement stack objects
Rework how the compiler+runtime handles stack-allocated variables
whose address is taken.

Direct references to such variables work as before. References through
pointers, however, use a new mechanism. The new mechanism is more
precise than the old "ambiguously live" mechanism. It computes liveness
at runtime based on the actual references among objects on the stack.

Each function records all of its address-taken objects in a FUNCDATA.
These are called "stack objects". The runtime then uses that
information while scanning a stack to find all of the stack objects on
a stack. It then does a mark phase on the stack objects, using all the
pointers found on the stack (and ancillary structures, like defer
records) as the root set. Only stack objects which are found to be
live during this mark phase will be scanned and thus retain any heap
objects they point to.

A subsequent CL will remove all the "ambiguously live" logic from
the compiler, so that the stack object tracing will be required.
For this CL, the stack tracing is all redundant with the current
ambiguously live logic.

Update #22350

Change-Id: Ide19f1f71a5b6ec8c4d54f8f66f0e9a98344772f
Reviewed-on: https://go-review.googlesource.com/c/134155
Reviewed-by: Austin Clements <austin@google.com>
2018-10-03 19:52:49 +00:00
Matthew Dempsky 433496615f cmd/compile/internal/gc: remove binary package export format
This CL removes all unused code from bimport.go and bexport.go.

In the interest of keeping this CL strictly delete-only and easier to
review, the task of consolidating the vestigial code elsewhere is left
to future CLs.

Change-Id: Ib757cc27e3fe814cbf534776d026e4d4cddfc6db
Reviewed-on: https://go-review.googlesource.com/c/139338
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2018-10-03 19:24:17 +00:00
Matthew Dempsky d546bebe34 cmd/compile/internal/gc: disable binary package export format
The new indexed package export format appears stable, and no reports
of needing to revert back to binary package export.

This CL disables the binary package export format by mechanically
replacing 'flagiexport' with 'true', and then superficial code
cleanups to keep the resulting code idiomatic. The resulting dead code
is removed in a followup CL.

Change-Id: Ic30d85f78778a31d279a56b9ab14e80836d50135
Reviewed-on: https://go-review.googlesource.com/c/139337
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2018-10-03 19:24:11 +00:00
Matthew Dempsky 02b444bc1d cmd/compile: use IsPtr instead of types.Tptr
Produced using gofmt -r.

Change-Id: I4184940618a3a1dac563a9d20aafe1d9f705300c
Reviewed-on: https://go-review.googlesource.com/c/76310
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-03 18:11:40 +00:00
Florian Uekermann 048de7b1fd time: return first error in unsuccessful calls to LoadLocation
Unsuccessful calls to LoadLocation previously returned the first
error encountered while traversing the default list of sources, but
ignored errors from sources specified by ZONEINFO. Whether errors
indicating missing zones or sources were ignored in this process
differed between kinds of sources.
With this change, unsuccessful calls to LoadLocation always return
the first error, not counting errors indicating missing zones or
sources.

Change-Id: Ief2c088f1df53d974b837e6565e784c2b9928ef4
Reviewed-on: https://go-review.googlesource.com/c/81595
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-03 17:40:17 +00:00
Tim 4559d58ced database/sql: improve unimplemented LastInsertId error message
The old one was rather confusing - it makes it sound like the user has done something wrong.

Change-Id: Ibc7411f4f1d5f6c66fbcaac64bb05b0743354418
GitHub-Last-Rev: 09290accdd
GitHub-Pull-Request: golang/go#27979
Reviewed-on: https://go-review.googlesource.com/c/139102
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-10-03 17:28:45 +00:00
David Url 0df9fa2ebe net/http: log call site which causes multiple header writes
If an illegal header write is detected, find the first caller outside of
net/http using runtime.CallersFrames and include the call site in the log
message.

Fixes #18761

Change-Id: I92be00ac206c6ebdd60344ad7bf40a7c4c188547
Reviewed-on: https://go-review.googlesource.com/c/130997
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-10-03 15:29:15 +00:00
Zhou Peng b8ac64a581 all: this big patch remove whitespace from assembly files
Don't worry, this patch just remove trailing whitespace from
assembly files, and does not touch any logical changes.

Change-Id: Ia724ac0b1abf8bc1e41454bdc79289ef317c165d
Reviewed-on: https://go-review.googlesource.com/c/113595
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-10-03 15:28:51 +00:00
Weerasak Chongnguluam 119fafcaa5 context: avoid duplicate removeChild
When deadline has already passed,
current context is canceled before return cancel function.
So is unnecessary to call cancel with remove from parent again
in return cancel function.

Change-Id: I37c687c57a29d9f139c7fb648ce7de69093ed623
Reviewed-on: https://go-review.googlesource.com/c/50410
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-03 15:26:10 +00:00
Cherry Zhang c96e3bcc97 cmd/compile: fix type of OffPtr in some optimization rules
In some optimization rules the type of generated OffPtr was
incorrectly set to the type of the pointee, instead of the
pointer. When the OffPtr value is spilled, this may generate
a spill of the wrong type, e.g. a floating point spill of an
integer (pointer) value. On Wasm, this leads to invalid
bytecode.

Fixes #27961.

Change-Id: I5d464847eb900ed90794105c0013a1a7330756cc
Reviewed-on: https://go-review.googlesource.com/c/139257
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Richard Musiol <neelance@gmail.com>
2018-10-03 15:01:47 +00:00
Anton Gyllenberg 54f5a6674a cmd/go: prevent infinite loop in QueryPackage()
p = path.Dir(p) converges to either "." or "/". The current
implementation of modload.QueryPackage() has a loop that
terminates only on ".", not "/". This leads to the go command
hanging in an infinite loop if the user manages to supply
a file path starting with "/" as package path.

An example of the issue is if the user (incorrectly) attempts
to use an absolute directory path in an import statement within
a module (import "/home/bob/myproj") and then runs go list.

Fixes #27558

Change-Id: Iaa6a4f7b05eba30609373636e50224ae2e7d6158
GitHub-Last-Rev: 3a70d3a427
GitHub-Pull-Request: golang/go#27976
Reviewed-on: https://go-review.googlesource.com/c/139098
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2018-10-03 13:57:04 +00:00
Clément Chigot a3a69afff8 cmd/dist: add AIX operating system.
This commit adds AIX operating system to cmd/dist package for ppc64
architecture.

The stack guard is increased because of syscalls made inside the runtime
which need a larger stack.

Disable cmd/vet/all tests until aix/ppc64 is fully available.

Change-Id: I7e3caf86724249ae564a152d90c1cbd4de288814
Reviewed-on: https://go-review.googlesource.com/c/138715
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-10-03 13:38:38 +00:00
Eduard Urbach 8919fe9e4d net/http: explain more how Pusher.Push works
This will clarify that the resources are not completely pushed yet when `Push` returns and that it starts a separate goroutine. This might be implementation dependant but as I believe there is currently only one implementation it should be added to the documentation of the interface which most people will look up first.

Change-Id: Id151c5563fd0c4e611eb1d93b4f64bf747ddf6d4
GitHub-Last-Rev: 1f46eb9a08
GitHub-Pull-Request: golang/go#25025
Reviewed-on: https://go-review.googlesource.com/c/108939
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-03 02:32:28 +00:00
Michael Henderson 06ff4772ab net/http: add missing words to SameSite doc/comments
Change-Id: Ie7f6592d726eba73a5e6b3203e083bff55ff8e4e
GitHub-Last-Rev: 4e317b39dd
GitHub-Pull-Request: golang/go#27977
Reviewed-on: https://go-review.googlesource.com/c/139100
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-03 02:09:38 +00:00
Ben Shi c3304edf10 cmd/internal/obj/arm: delete unnecessary code
In the arm assembler, "AMOVW" never falls into optab
case 13, so the check "if p.As == AMOVW" is useless.

Change-Id: Iec241d5b4cffb358a1477f470619dc9a6287884a
Reviewed-on: https://go-review.googlesource.com/c/138575
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-10-03 01:05:56 +00:00
Brad Fitzpatrick a73d8f5a86 net/http: make Transport send WebSocket upgrade requests over HTTP/1
WebSockets requires HTTP/1 in practice (no spec or implementations
work over HTTP/2), so if we get an HTTP request that looks like it's
trying to initiate WebSockets, use HTTP/1, like browsers do.

This is part of a series of commits to make WebSockets work over
httputil.ReverseProxy. See #26937.

Updates #26937

Change-Id: I6ad3df9b0a21fddf62fa7d9cacef48e7d5d9585b
Reviewed-on: https://go-review.googlesource.com/c/137437
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
2018-10-02 23:33:23 +00:00
Aleksandr Razumov 3aa3c052e3 net/http: rewind request body unconditionally
When http2 fails with ErrNoCachedConn the request is retried with body
that has already been read.

Fixes #25009

Change-Id: I51ed5c8cf469dd8b17c73fff6140ab80162bf267
Reviewed-on: https://go-review.googlesource.com/c/131755
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 21:11:23 +00:00
Austin Clements 0906d648aa runtime: eliminate gchelper mechanism
Now that we do no mark work during mark termination, we no longer need
the gchelper mechanism.

Updates #26903.
Updates #17503.

Change-Id: Ie94e5c0f918cfa047e88cae1028fece106955c1b
Reviewed-on: https://go-review.googlesource.com/c/134785
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:38 +00:00
Austin Clements 550dfc8ae1 runtime: eliminate work.markrootdone and second root marking pass
Before STW and concurrent GC were unified, there could be either one
or two root marking passes per GC cycle. There were several tasks we
had to make sure happened once and only once (whether that was at the
beginning of concurrent mark for concurrent GC or during mark
termination for STW GC). We kept track of this in work.markrootdone.

Now that STW and concurrent GC both use the concurrent marking code
and we've eliminated all work done by the second root marking pass, we
only ever need a single root marking pass. Hence, we can eliminate
work.markrootdone and all of the code that's conditional on it.

Updates #26903.

Change-Id: I654a0f5e21b9322279525560a31e64b8d33b790f
Reviewed-on: https://go-review.googlesource.com/c/134784
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:37 +00:00
Austin Clements 873bd47dfb runtime: flush mcaches lazily
Currently, all mcaches are flushed during STW mark termination as a
root marking job. This is currently necessary because all spans must
be out of these caches before sweeping begins to avoid races with
allocation and to ensure the spans are in the state expected by
sweeping. We do it as a root marking job because mcache flushing is
somewhat expensive and O(GOMAXPROCS) and this parallelizes the work
across the Ps. However, it's also the last remaining root marking job
performed during mark termination.

This CL moves mcache flushing out of mark termination and performs it
lazily. We keep track of the last sweepgen at which each mcache was
flushed and as each P is woken from STW, it observes that its mcache
is out-of-date and flushes it.

The introduces a complication for spans cached in stale mcaches. These
may now be observed by background or proportional sweeping or when
attempting to add a finalizer, but aren't in a stable state. For
example, they are likely to be on the wrong mcentral list. To fix
this, this CL extends the sweepgen protocol to also capture whether a
span is cached and, if so, whether or not its cache is stale. This
protocol blocks asynchronous sweeping from touching cached spans and
makes it the responsibility of mcache flushing to sweep the flushed
spans.

This eliminates the last mark termination root marking job, which
means we can now eliminate that entire infrastructure.

Updates #26903. This implements lazy mcache flushing.

Change-Id: Iadda7aabe540b2026cffc5195da7be37d5b4125e
Reviewed-on: https://go-review.googlesource.com/c/134783
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:35 +00:00
Austin Clements 457c8f4fe9 runtime: eliminate blocking GC work drains
Now work.helperDrainBlock is always false, so we can remove it and
code paths that only ran when it was true. That means we no longer use
the gcDrainBlock mode of gcDrain, so we can eliminate that. That means
we no longer use gcWork.get, so we can eliminate that. That means we
no longer use getfull, so we can eliminate that.

Updates #26903. This is a follow-up to unifying STW GC and concurrent GC.

Change-Id: I8dbcf8ce24861df0a6149e0b7c5cd0eadb5c13f6
Reviewed-on: https://go-review.googlesource.com/c/134782
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:34 +00:00
Austin Clements 143b13ae82 runtime: clean up remaining mark work check
Now that STW GC marking is unified with concurrent marking, there
should never be mark work remaining in mark termination. Hence, we can
make that check unconditional.

Updates #26903. This is a follow-up to unifying STW GC and concurrent GC.

Change-Id: I43a21df5577635ab379c397a7405ada68d331e03
Reviewed-on: https://go-review.googlesource.com/c/134781
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:32 +00:00
Austin Clements 1678b2c580 runtime: implement STW GC in terms of concurrent GC
Currently, STW GC works very differently from concurrent GC. The
largest differences in that in concurrent GC, all marking work is done
by background mark workers during the mark phase, while in STW GC, all
marking work is done by gchelper during the mark termination phase.

This is a consequence of the evolution of Go's GC from a STW GC by
incrementally moving work from STW mark termination into concurrent
mark. However, at this point, the STW code paths exist only as a
debugging mode. Having separate code paths for this increases the
maintenance burden and complexity of the garbage collector. At the
same time, these code paths aren't tested nearly as well, making it
far more likely that they will bit-rot.

This CL reverses the relationship between STW GC, by re-implementing
STW GC in terms of concurrent GC.

This builds on the new scheduled support for disabling user goroutine
scheduling. During sweep termination, it disables user scheduling, so
when the GC starts the world again for concurrent mark, it's really
only "concurrent" with itself.

There are several code paths that were specific to STW GC that are now
vestigial. We'll remove these in the follow-up CLs.

Updates #26903.

Change-Id: Ia3883d2fcf7ab1d89bdc9c8ee54bf9bffb32c096
Reviewed-on: https://go-review.googlesource.com/c/134780
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:31 +00:00
Austin Clements 6e9fb11b3a runtime: support disabling goroutine scheduling by class
This adds support for disabling the scheduling of user goroutines
while allowing system goroutines like the garbage collector to
continue running. User goroutines pass through the usual state
transitions, but if we attempt to actually schedule one, it will get
put on a deferred scheduling list.

Updates #26903. This is preparation for unifying STW GC and concurrent
GC.

Updates #25578. This same mechanism can form the basis for disabling
all but a single user goroutine for the purposes of debugger function
call injection.

Change-Id: Ib72a808e00c25613fe6982f5528160d3de3dbbc6
Reviewed-on: https://go-review.googlesource.com/c/134779
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:29 +00:00
Austin Clements 29b21ec4c3 runtime: add a more stable isSystemGoroutine mode
Currently, isSystemGoroutine varies on whether it considers the
finalizer goroutine a user goroutine or a system goroutine. For the
next CL, we're going to want to always consider the finalier goroutine
a user goroutine, so add a flag that indicates that.

Updates #26903. This is preparation for unifying STW GC and concurrent
GC.

Change-Id: Iafc92e519c13d9f8d879332cb5f0d12164104c33
Reviewed-on: https://go-review.googlesource.com/c/134778
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:28 +00:00
Austin Clements 198440cc3d runtime: remove GODEBUG=gcrescanstacks=1 mode
Currently, setting GODEBUG=gcrescanstacks=1 enables a debugging mode
where the garbage collector re-scans goroutine stacks during mark
termination. This was introduced in Go 1.8 to debug the hybrid write
barrier, but I don't think we ever used it.

Now it's one of the last sources of mark work during mark termination.
This CL removes it.

Updates #26903. This is preparation for unifying STW GC and concurrent
GC.

Updates #17503.

Change-Id: I6ae04d3738aa9c448e6e206e21857a33ecd12acf
Reviewed-on: https://go-review.googlesource.com/c/134777
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:27 +00:00
Austin Clements ecc365960b runtime: avoid using STW GC mechanism for checkmarks mode
Currently, checkmarks mode uses the full STW GC infrastructure to
perform mark checking. We're about to remove that infrastructure and,
furthermore, since checkmarks is about doing the simplest thing
possible to check concurrent GC, it's valuable for it to be simpler.

Hence, this CL makes checkmarks even simpler by making it non-parallel
and divorcing it from the STW GC infrastructure (including the
gchelper mechanism).

Updates #26903. This is preparation for unifying STW GC and concurrent
GC.

Change-Id: Iad21158123e025e3f97d7986d577315e994bd43e
Reviewed-on: https://go-review.googlesource.com/c/134776
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:26 +00:00
Austin Clements 918ed88e47 runtime: remove gcStart's mode argument
This argument is always gcBackgroundMode since only
debug.gcstoptheworld can trigger a STW GC at this point. Remove the
unnecessary argument.

Updates #26903. This is preparation for unifying STW GC and concurrent
GC.

Change-Id: Icb4ba8f10f80c2b69cf51a21e04fa2c761b71c94
Reviewed-on: https://go-review.googlesource.com/c/134775
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:24 +00:00
Austin Clements e25ef35254 runtime: don't disable GC work caching during mark termination
Currently, we disable GC work caching during mark termination. This is
no longer necessary with the new mark completion detection because

1. There's no way for any of the GC mark termination helpers to have
any real work queued and,

2. Mark termination has to explicitly flush every P's buffers anyway
in order to flush Ps that didn't run a GC mark termination helper.

Hence, remove the code that disposes gcWork buffers during mark
termination.

Updates #26903. This is a follow-up to eliminating mark 2.

Change-Id: I81f002ee25d5c10f42afd39767774636519007f9
Reviewed-on: https://go-review.googlesource.com/c/134320
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:23 +00:00
Austin Clements d398dbdfc3 runtime: eliminate gcBlackenPromptly mode
Now that there is no mark 2 phase, gcBlackenPromptly is no longer
used.

Updates #26903. This is a follow-up to eliminating mark 2.

Change-Id: Ib9c534f21b36b8416fcf3cab667f186167b827f8
Reviewed-on: https://go-review.googlesource.com/c/134319
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:21 +00:00
Austin Clements 9108ae7751 runtime: eliminate mark 2 and fix mark termination race
The mark 2 phase was originally introduced as a way to reduce the
chance of entering STW mark termination while there was still marking
work to do. It works by flushing and disabling all local work caches
so that all enqueued work becomes immediately globally visible.
However, mark 2 is not only slow–disabling caches makes marking and
the write barrier both much more expensive–but also imperfect. There
is still a rare but possible race (~once per all.bash) that can cause
GC to enter mark termination while there is still marking work. This
race is detailed at
https://github.com/golang/proposal/blob/master/design/17503-eliminate-rescan.md#appendix-mark-completion-race
The effect of this is that mark termination must still cope with the
possibility that there may be work remaining after a concurrent mark
phase. Dealing with this increases STW pause time and increases the
complexity of mark termination.

Furthermore, a similar but far more likely race can cause early
transition from mark 1 to mark 2. This is unfortunate because it
causes performance instability because of the cost of mark 2.

This CL fixes this by replacing mark 2 with a distributed termination
detection algorithm. This algorithm is correct, so it eliminates the
mark termination race, and doesn't require disabling local caches. It
ensures that there are no grey objects upon entering mark termination.
With this change, we're one step closer to eliminating marking from
mark termination entirely (it's still used by STW GC and checkmarks
mode).

This CL does not eliminate the gcBlackenPromptly global flag, though
it is always set to false now. It will be removed in a cleanup CL.

This led to only minor variations in the go1 benchmarks
(https://perf.golang.org/search?q=upload:20180909.1) and compilebench
benchmarks (https://perf.golang.org/search?q=upload:20180910.2).

This significantly improves performance of the garbage benchmark, with
no impact on STW times:

name                        old time/op    new time/op   delta
Garbage/benchmem-MB=64-12    2.21ms ± 1%   2.05ms ± 1%   -7.38% (p=0.000 n=18+19)
Garbage/benchmem-MB=1024-12  2.30ms ±16%   2.20ms ± 7%   -4.51% (p=0.001 n=20+20)

name                        old STW-ns/GC  new STW-ns/GC  delta
Garbage/benchmem-MB=64-12      138k ±44%     141k ±23%     ~    (p=0.309 n=19+20)
Garbage/benchmem-MB=1024-12    159k ±25%     178k ±98%     ~    (p=0.798 n=16+18)

name                        old STW-ns/op  new STW-ns/op                delta
Garbage/benchmem-MB=64-12     4.42k ±44%    4.24k ±23%     ~    (p=0.531 n=19+20)
Garbage/benchmem-MB=1024-12     591 ±24%      636 ±111%    ~    (p=0.309 n=16+18)

(https://perf.golang.org/search?q=upload:20180910.1)

Updates #26903.
Updates #17503.

Change-Id: Icbd1e12b7a12a76f423c9bf033b13cb363e4cd19
Reviewed-on: https://go-review.googlesource.com/c/134318
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:20 +00:00
Austin Clements a2a2901b25 runtime: track whether any buffer has been flushed from gcWork
Nothing currently consumes the flag, but we'll use it in the
distributed termination detection algorithm.

Updates #26903. This is preparation for eliminating mark 2.

Change-Id: I5e149a05b1c878fe1009150da21f8bd8ae2b9b6a
Reviewed-on: https://go-review.googlesource.com/c/134317
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:19 +00:00
Austin Clements edc2d17086 runtime: remove GODEBUG=gctrace=2 mode
It turns out if you set GODEBUG=gctrace=2, it enables an obscure
debugging mode that, in addition to printing gctrace statistics, also
does a second STW GC following each regular GC. This debugging mode
has long since lost its value (you could maybe use it to analyze
floating garbage, except that we don't print the gctrace line on the
second GC), and it interferes substantially with the operation of the
GC by messing up the statistics used to schedule GCs.

It's also a source of mark termination GC work when we're in
concurrent GC mode, so it's going to interfere with eliminating mark
2. And it's going to get in the way of unifying STW and concurrent GC.

This CL removes this debugging mode.

Updates #26903. This is preparation for eliminating mark 2 and
unifying STW GC and concurrent GC.

Change-Id: Ib5bce05d8c4d5b6559c89a65165d49532165df07
Reviewed-on: https://go-review.googlesource.com/c/134316
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:17 +00:00
Austin Clements 9c634ea889 runtime: flush write barrier buffer to create work
Currently, if the gcWork runs out of work, we'll fall out of the GC
worker, even though flushing the write barrier buffer could produce
more work. While this is not a correctness issue, it can lead to
premature mark 2 or mark termination.

Fix this by flushing the write barrier buffer if the local gcWork runs
out of work and then checking the local gcWork again.

This reduces the number of premature mark terminations during all.bash
by about a factor of 10.

Updates #26903. This is preparation for eliminating mark 2.

Change-Id: I48577220b90c86bfd28d498e8603bc379a8cd617
Reviewed-on: https://go-review.googlesource.com/c/134315
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2018-10-02 20:35:15 +00:00
Daniel Theophanes 7db509e682 database/sql: correctly report MaxIdleClosed stat
Previously the MaxIdleClosed counter was incremented when added
to the free connection list, rather then when it wasn't added
to the free connection list. Flip this logic to correct.

Fixes #27792

Change-Id: I405302c14fb985369dab48fbe845e5651afc4ccf
Reviewed-on: https://go-review.googlesource.com/c/138578
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 19:24:37 +00:00
Carlos Eduardo Seo 9aed4cc395 cmd/compile: instrinsify math/bits.Mul on ppc64x
Add SSA rules to intrinsify Mul/Mul64 on ppc64x.

benchmark             old ns/op     new ns/op     delta
BenchmarkMul-40       8.80          0.93          -89.43%
BenchmarkMul32-40     1.39          1.39          +0.00%
BenchmarkMul64-40     5.39          0.93          -82.75%

Updates #24813

Change-Id: I6e95bfbe976a2278bd17799df184a7fbc0e57829
Reviewed-on: https://go-review.googlesource.com/138917
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
2018-10-02 18:56:06 +00:00
Robert Griesemer f5e58442da cmd/compile: update fmt_test (fix build for long-running tests)
Follow-up on https://golang.org/cl/136397.

Change-Id: Ib0df690847c7c92d8de406dadc16a10507bfda39
Reviewed-on: https://go-review.googlesource.com/c/139059
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-10-02 18:28:06 +00:00
Richard Musiol e5489cfc12 misc/wasm: add mention of polyfill for Edge support
Edge supports WebAssembly but not TextEncoder or TextDecoder.
This change adds a comment pointing to a polyfill that could
be used. The polyfill is not added by default, because we want to
let the user decide if/how to include the polyfill.

Fixes #27295

Change-Id: I375f58f2168665f549997b368428c398dfbbca1c
Reviewed-on: https://go-review.googlesource.com/139037
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 17:25:11 +00:00
Brad Fitzpatrick ed969a0c27 Revert "misc/wasm: add polyfill for TextEncoder/TextDecoder for Edge support"
This reverts CL 131718, commit a0e7f12771.

Reason for revert: adds request overhead & dependency on third-party service for all users regardless of whether it's necessary.

Updates #27295

Change-Id: I4a8a9b0c8e4a3198c884dfbd90ba36734f70a9a9
Reviewed-on: https://go-review.googlesource.com/138937
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 17:25:00 +00:00
Muhammad Falak R Wani 9ec5d9c15b net/http: document Header.Set canonicalizes the header key
Fixes #27923

Change-Id: Ia902a1966beeae56e43265fc5ed987555fa834b6
Reviewed-on: https://go-review.googlesource.com/138677
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 17:07:42 +00:00
esell 3ee9672955 net/http: add Handle example
Currently there is no example for http.Handle in the
documentation. This adds an example.

Change-Id: I66ee9983bea1f5237757e1ef4956eae9a056e963
Reviewed-on: https://go-review.googlesource.com/137715
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-02 16:59:25 +00:00
Alex Brainman de72c43f78 net: skip TestUnixConnLocalWindows on windows/386
Recent CL 125456 implemented Unix Socket functionality on windows.
But that functionality does not appear to be working when 32-bit
code is used. So disable TestUnixConnLocalWindows.

windows/386 builder does not appear to be complaining about
TestUnixConnLocalWindows, because new functionality requires
Windows 10 Build 17063. windows/386 builder uses Windows 2008.

Fixes #27943

Change-Id: Iea91b86aaa124352d198ca0cd03fff1e7542f949
Reviewed-on: https://go-review.googlesource.com/138676
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Yasuhiro MATSUMOTO <mattn.jp@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-10-02 09:49:44 +00:00
Robert Griesemer 5d444e36a6 cmd/compile/internal/gc: add alternative node dumper for debugging
dump/fdump is a reflection-based data structure dumper slightly
customized for the compiler's Node data structure. It dumps the
transitivle closure of Node (and other) data structures using a
recursive descent depth first traversal and permits filtering
options (recursion depth limitation, filtering of struct fields).

I have been using it to diagnose compiler bugs and found it more
useful than the existing node printing code in some cases because
field filtering reduces the output to the interesting parts.

No impact on rest of compiler if functions are not called (which
they only should during a debugging session).

Change-Id: I79d7227f10dd78dbd4bbcdf204db236102fc97a7
Reviewed-on: https://go-review.googlesource.com/136397
Reviewed-by: Alan Donovan <adonovan@google.com>
2018-10-01 21:53:00 +00:00
Katie Hockman f99fc3a119 doc: document Go 1.11.1
Change-Id: I2f1a55e15dc5737a5a06bd894c46b2c4705f338c
Reviewed-on: https://go-review.googlesource.com/138858
Reviewed-by: Filippo Valsorda <filippo@golang.org>
2018-10-01 20:32:50 +00:00
Shulhan a9c69e0a65 runtime: fix runtime gdb test with gdb v8.2
Previously, some of output from gdb matched with literal string, while
gdb v8.2 print the address of variable (e.g. map key and value) in
output.

This commit fix the regex in testing the output.

Fixes #27608

Change-Id: Ic3fe8280b9f93fda2799116804822616caa66beb
Reviewed-on: https://go-review.googlesource.com/135055
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2018-10-01 19:21:42 +00:00
Ian Davis b57ccdf992 image: optimize bounds checking for At and Set methods
Use a subslice of the pixel data to give the compiler hints
for bounds checking. Only do this for image formats that
require 4 or more slice reads/writes.

See #27857 for discussion of small cap sizes.

name                   old time/op    new time/op    delta
At/rgba-8              18.8ns ± 2%    18.5ns ± 1%   -1.49%  (p=0.026 n=10+10)
At/rgba64-8            22.2ns ± 2%    21.1ns ± 3%   -4.51%  (p=0.000 n=10+10)
At/nrgba-8             18.8ns ± 2%    18.7ns ± 2%     ~     (p=0.467 n=10+10)
At/nrgba64-8           21.9ns ± 2%    21.0ns ± 2%   -4.15%  (p=0.000 n=10+9)
At/alpha-8             14.3ns ± 1%    14.3ns ± 2%     ~     (p=0.543 n=10+10)
At/alpha16-8           6.43ns ± 1%    6.47ns ± 1%     ~     (p=0.053 n=10+10)
At/gray-8              14.4ns ± 2%    14.6ns ± 5%     ~     (p=0.194 n=10+10)
At/gray16-8            6.52ns ± 1%    6.55ns ± 2%     ~     (p=0.610 n=10+10)
At/paletted-8          4.17ns ± 1%    4.21ns ± 2%     ~     (p=0.095 n=9+10)
Set/rgba-8             39.2ns ± 2%    40.1ns ± 4%   +2.45%  (p=0.007 n=10+10)
Set/rgba64-8           46.2ns ± 3%    43.3ns ± 3%   -6.11%  (p=0.000 n=10+10)
Set/nrgba-8            39.2ns ± 1%    39.7ns ± 5%     ~     (p=0.407 n=10+10)
Set/nrgba64-8          45.6ns ± 3%    42.9ns ± 3%   -5.83%  (p=0.000 n=9+10)
Set/alpha-8            35.0ns ± 3%    34.1ns ± 2%   -2.43%  (p=0.017 n=10+10)
Set/alpha16-8          36.3ns ± 4%    35.8ns ± 5%     ~     (p=0.254 n=10+10)
Set/gray-8             19.8ns ± 1%    19.7ns ± 0%   -0.69%  (p=0.002 n=8+6)
Set/gray16-8           36.0ns ± 1%    36.4ns ± 2%   +1.08%  (p=0.037 n=10+10)
Set/paletted-8         39.1ns ± 0%    39.6ns ± 1%   +1.30%  (p=0.000 n=10+10)
RGBAAt-8               3.72ns ± 1%    3.58ns ± 1%   -3.76%  (p=0.000 n=9+10)
RGBASetRGBA-8          4.35ns ± 1%    3.70ns ± 1%  -14.92%  (p=0.000 n=10+10)
RGBA64At-8             5.08ns ± 1%    3.69ns ± 1%  -27.40%  (p=0.000 n=9+9)
RGBA64SetRGBA64-8      6.65ns ± 2%    3.63ns ± 0%  -45.35%  (p=0.000 n=10+9)
NRGBAAt-8              3.72ns ± 1%    3.59ns ± 1%   -3.55%  (p=0.000 n=10+10)
NRGBASetNRGBA-8        4.05ns ± 0%    3.71ns ± 1%   -8.57%  (p=0.000 n=9+10)
NRGBA64At-8            4.99ns ± 1%    3.69ns ± 0%  -26.07%  (p=0.000 n=10+9)
NRGBA64SetNRGBA64-8    6.66ns ± 1%    3.64ns ± 1%  -45.40%  (p=0.000 n=10+10)
AlphaAt-8              1.44ns ± 1%    1.44ns ± 0%     ~     (p=0.176 n=10+7)
AlphaSetAlpha-8        1.60ns ± 2%    1.56ns ± 0%   -2.62%  (p=0.000 n=10+6)
Alpha16At-8            2.87ns ± 1%    2.92ns ± 2%   +1.67%  (p=0.001 n=10+10)
AlphaSetAlpha16-8      3.26ns ± 1%    3.35ns ± 1%   +2.68%  (p=0.012 n=8+3)

Fixes #14884

Change-Id: Ia0383530596a550e1b1c7aafce5220e5e0935a53
Reviewed-on: https://go-review.googlesource.com/137495
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-10-01 19:16:00 +00:00
Katie Hockman 43cd907017 Revert "compress: move benchmark text from src/testdata to src/compress/testdata"
This reverts commit 067bb443af.

Reason for revert:
Failing Darwin-arm builds because that testing environment does not access testdata
from sibling directories. A future change will likely be made to move this testdata
out of src/testdata to create a solution that doesn't require the single-file directory.

Updates #27151

Change-Id: I8dbf5dd9512c94a605ee749ff4655cb00b0de686
Reviewed-on: https://go-review.googlesource.com/138737
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
2018-10-01 16:16:21 +00:00
Keith Randall 0b994a9037 reflect: fix s390x reflect method calls
R0 isn't the zero register any more. Oops.

Update #27695.

Change-Id: I46a975ed37d5e570afe2e228d3edf74949e08ad7
Reviewed-on: https://go-review.googlesource.com/138580
Reviewed-by: Michael Munday <mike.munday@ibm.com>
2018-09-30 20:30:55 +00:00
Keith Randall ef50373983 reflect: ensure correct scanning of return values
During a call to a reflect-generated function or method (via
makeFuncStub or methodValueCall), when should we scan the return
values?

When we're starting a reflect call, the space on the stack for the
return values is not initialized yet, as it contains whatever junk was
on the stack of the caller at the time. The return space must not be
scanned during a GC.

When we're finishing a reflect call, the return values are
initialized, and must be scanned during a GC to make sure that any
pointers in the return values are found and their referents retained.

When the GC stack walk comes across a reflect call in progress on the
stack, it needs to know whether to scan the results or not. It doesn't
know the progress of the reflect call, so it can't decide by
itself. The reflect package needs to tell it.

This CL adds another slot in the frame of makeFuncStub and
methodValueCall so we can put a boolean in there which tells the
runtime whether to scan the results or not.

This CL also adds the args length to reflectMethodValue so the
runtime can restrict its scanning to only the args section (not the
results) if the reflect package says the results aren't ready yet.

Do a delicate dance in the reflect package to set the "results are
valid" bit. We need to make sure we set the bit only after we've
copied the results back to the stack. But we must set the bit before
we drop reflect's copy of the results. Otherwise, we might have a
state where (temporarily) no one has a live copy of the results.
That's the state we were observing in issue #27695 before this CL.

The bitmap used by the runtime currently contains only the args.
(Actually, it contains all the bits, but the size is set so we use
only the args portion.) This is safe for early in a reflect call, but
unsafe late in a reflect call. The test issue27695.go demonstrates
this unsafety. We change the bitmap to always include both args
and results, and decide at runtime which portion to use.

issue27695.go only has a test for method calls. Function calls were ok
because there wasn't a safepoint between when reflect dropped its copy
of the return values and when the caller is resumed. This may change
when we introduce safepoints everywhere.

This truncate-to-only-the-args was part of CL 9888 (in 2015). That
part of the CL fixed the problem demonstrated in issue27695b.go but
introduced the problem demonstrated in issue27695.go.

TODO, in another CL: simplify FuncLayout and its test. stack return
value is now identical to frametype.ptrdata + frametype.gcdata.

Fixes #27695

Change-Id: I2d49b34e34a82c6328b34f02610587a291b25c5f
Reviewed-on: https://go-review.googlesource.com/137440
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2018-09-29 20:25:24 +00:00