When scavenging small amounts it's possible we over-scavenge by a
significant margin since we choose to scavenge the largest spans first.
This over-scavenging is never accounted for.
With this change, we add a scavenge credit pool, similar to the reclaim
credit pool. Any time scavenging triggered by RSS growth starts up, it
checks if it can cash in some credit first. If after using all the
credit it still needs to scavenge, then any extra it does it adds back
into the credit pool.
This change mitigates the performance impact of golang.org/cl/159500 on
the Garbage benchmark. On Go1 it suggests some improvements, but most of
that is within the realm of noise (Revcomp seems very sensitive to
GC-related changes, both postively and negatively).
Garbage: https://perf.golang.org/search?q=upload:20190131.5
Go1: https://perf.golang.org/search?q=upload:20190131.4
Performance change with both changes:
Garbage: https://perf.golang.org/search?q=upload:20190131.7
Go1: https://perf.golang.org/search?q=upload:20190131.6
Change-Id: I87bd3c183e71656fdafef94714194b9fdbb77aa2
Reviewed-on: https://go-review.googlesource.com/c/160297
Reviewed-by: Austin Clements <austin@google.com>
Because scavenged and unscavenged spans no longer coalesce, memory that
is freed no longer has a high likelihood of being re-scavenged. As a
result, if an application is allocating at a fast rate, it may work fast
enough to undo all the scavenging work performed by the runtime's
current scavenging mechanisms. This behavior is exacerbated by the
global best-fit allocation policy the runtime uses, since scavenged
spans are just as likely to be chosen as unscavenged spans on average.
To remedy that, we treat each allocation of scavenged space as a heap
growth, and scavenge other memory to make up for the allocation.
This change makes performance of the runtime slightly worse, as now
we're scavenging more often during allocation. The regression is
particularly obvious with the garbage benchmark (3%) but most of the Go1
benchmarks are within the margin of noise. A follow-up change should
help.
Garbage: https://perf.golang.org/search?q=upload:20190131.3
Go1: https://perf.golang.org/search?q=upload:20190131.2
Updates #14045.
Change-Id: I44a7e6586eca33b5f97b6d40418db53a8a7ae715
Reviewed-on: https://go-review.googlesource.com/c/159500
Reviewed-by: Austin Clements <austin@google.com>
GCC 9 has started emitting warnings when taking the address of a field
in a packed struct may cause a misaligned pointer. We use packed
structs in cgo to ensure that our field layout matches the C
compiler's layout. Our pointers are always aligned, so disable the warning
Fixes#29962
Change-Id: I7e290a7cf694a2c2958529e340ebed9fcd62089c
Reviewed-on: https://go-review.googlesource.com/c/159859
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
This update has been automatically generated using the updatecontrib
command at CL 160277:
cd gotip
go run golang.org/x/build/cmd/updatecontrib
Actions taken (relative to CONTRIBUTORS at origin/master):
Added Aaron Cannon <cannona@fireantproductions.com>
Added Andzej Maciusovic <andzej.maciusovic@gmail.com>
Added Douglas Danger Manley <doug.manley@gmail.com>
Added Federico Bond <federicobond@gmail.com>
Added Frew Schmidt <github@frew.co>
Added GitHub User @saitarunreddy (21041941) <saitarunreddypalla@gmail.com>
Added GitHub User @tell-k (26263) <ffk2005@gmail.com>
Added Guilherme Caruso <gui.martinscaruso@gmail.com>
Added Jay Taylor <outtatime@gmail.com>
Added Juan Pablo Civile <elementohb@gmail.com>
Added Julien Kauffmann <julien.kauffmann@freelan.org>
Added Maya Rashish <maya@NetBSD.org>
Added Parminder Singh <parmsingh101@gmail.com>
Added Peter Dotchev <dotchev@gmail.com>
Added Quinten Yearsley <qyearsley@chromium.org>
Added Ross Smith II <ross@smithii.com>
Added Sean Chen <oohcode@gmail.com>
Added Sebastiaan van Stijn <github@gone.nl>
Added Sebastian Schmidt <yath@google.com>
Added Sebastien Williams-Wynn <sebastien@cytora.com>
Added Viacheslav Poturaev <vearutop@gmail.com>
Added Yohei Takeda <yo.tak0812@gmail.com>
Used GitHub User @saitarunreddy (21041941) form for saitarunreddy <saitarunreddypalla@gmail.com> https://github.com/golang/build/commit/269e03a [build]
Used GitHub User @tell-k (26263) form for tell-k <ffk2005@gmail.com> https://github.com/golang/tools/commit/85a87a81 [tools]
Used GitHub name "Akhil Indurti" for smasher164 <aindurti@gmail.com> https://github.com/golang/go/commit/a7af474359 [build go]
Used GitHub name "Guilherme Caruso" for GuilhermeCaruso <gui.martinscaruso@gmail.com> https://github.com/golang/go/commit/5fae09b738 [go]
Used GitHub name "Ivan Markin" for nogoegst <nogoegst@users.noreply.github.com> https://github.com/golang/go/commit/a1addf15df [go]
Used GitHub name "Keiji Yoshida" for yosssi <yoshida.keiji.84@gmail.com> https://github.com/golang/lint/commit/ac6833c [lint]
Used GitHub name "Marwan Sulaiman" for marwan-at-work <marwan.sameer@gmail.com> https://github.com/golang/go/commit/92caeef892 [go]
Used GitHub name "Michalis Kargakis" for kargakis <mkargaki@redhat.com> https://github.com/golang/go/commit/e243d242d7 [go]
Used GitHub name "Robin Eklind" for mewmew <rnd0x00@gmail.com> https://github.com/golang/go/commit/b8620afb8d [go proposal.git]
Used GitHub name "Sean Chen" for two <oohcode@gmail.com> https://github.com/golang/sys/commit/302c3dd [sys]
Used GitHub name "Sebastien Williams-Wynn" for GiantsLoveDeathMetal <sebastien@cytora.com> https://github.com/golang/go/commit/4e056ade24 [go]
Used GitHub name "Yohei Takeda" for yo-tak <yo.tak0812@gmail.com> https://github.com/golang/go/commit/8b7cf898af [go]
Given that the scope of updatecontrib is only to add contributors to
CONTRIBUTORS file, without having to check CLAs or deal with legal
matters, we can relax the requirement of having a space in the name
before it gets added to the CONTRIBUTORS file. That will be done
in a later change.
Updates #12042
Change-Id: I70248f3c82a836ee829256898e931e638ee45eb4
Reviewed-on: https://go-review.googlesource.com/c/160261
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Note the removal of the go tool tour command in the Go 1.12 release
notes.
Updates #24819
Change-Id: I258ab9401ea2cc06a83328c67299376fcf23c980
Reviewed-on: https://go-review.googlesource.com/c/158618
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
- add EINTR loop on Darwin
- return PathError on error
- call newFile rather than NewFile
This tries to minimize the possibility of any future changes.
It would be nice to put openFdAt in the same file as openFileNolog,
but build tags forbid.
Updates #29983
Change-Id: I866002416d6473fbfd80ff6ef09b2bc4607f2934
Reviewed-on: https://go-review.googlesource.com/c/160181
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
CL 159157 was doing UTF-8 decoding of URLs. URLs aren't really UTF-8,
even if sometimes they are in some contexts.
Instead, only reject ASCII CTLs.
Updates #27302
Updates #22907
Change-Id: Ibd64efa5d3a93263d175aadf1c9f87deb4670c62
Reviewed-on: https://go-review.googlesource.com/c/160178
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, if an assembly file includes a static reference to an
undefined symbol, and another package also has an undefined reference
to that symbol, the linker can report an error like:
x: relocation target zero not defined for ABI0 (but is defined for ABI0)
Since the symbol is referenced in another package, the code in
ErrorUnresolved that looks for alternative ABI symbols finds that
symbol in the symbol table, but doesn't check that it's actually
defined, which is where the "but is defined for ABI0" comes from. The
"not defined for ABI0" is because ErrorUnresolved failed to turn the
static symbol's version back into an ABI, and it happened to print the
zero value for an ABI.
This CL fixes both of these problems. It explicitly maps the
relocation version back to an ABI and detects if it can't be mapped
back (e.g., because it's a static reference). Then, if it finds a
symbol with a different ABI in the symbol table, it checks to make
sure it's a definition, and not simply an unresolved reference.
Fixes#29852.
Change-Id: Ice45cc41c1907919ce5750f74588e8047eaa888c
Reviewed-on: https://go-review.googlesource.com/c/159518
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestIssue29372 is broken on windows when temporary directory has
symlink in its path.
Adjust the test to use filepath.EvalSymlinks of temporary directory,
instead of temporary directory on windows. This change is not a
proper fix, but at least it makes TestIssue29372 pass on windows-arm.
See issue for details.
Updates #29746
Change-Id: I2af8ebb89da7cb9daf027a5e49e32ee22dbd0e3d
Reviewed-on: https://go-review.googlesource.com/c/159578
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Treat compiler-generated init functions as wrappers, so they will not
be shown in tracebacks.
The exception to this rule is that we'd like to show the line number
of initializers for global variables in tracebacks. In order to
preserve line numbers for those cases, separate out the code for those
initializers into a separate function (which is not marked as
autogenerated).
This CL makes the go binary 0.2% bigger.
Fixes#29919
Change-Id: I0f1fbfc03d10d764ce3a8ddb48fb387ca8453386
Reviewed-on: https://go-review.googlesource.com/c/159717
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Whether a truncation should become a MOVWreg or a MOVWZreg doesn't
depend on the type of the operand, it depends on the type of the final
result. If the final result is unsigned, we can use MOVWZreg. If the
final result is signed, we can use MOVWreg. Checking the type of the
operand does the wrong thing if truncating an unsigned value to a
signed value, or vice-versa.
Fixes#29943
Change-Id: Ia6fc7d006486fa02cffd0bec4d910bdd5b6365f8
Reviewed-on: https://go-review.googlesource.com/c/159760
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Fixes#26533
Change-Id: I5a48d667d474f3f222f9055e51131561a0cf45b6
Reviewed-on: https://go-review.googlesource.com/c/138757
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If beta8 is unusually large, the addition loop might take a very long
time to bring x3-beta8 back positive.
This would lead to a DoS vulnerability in the implementation of the
P-521 and P-384 elliptic curves that may let an attacker craft inputs
to ScalarMult that consume excessive amounts of CPU.
This fixes CVE-2019-6486.
Fixes#29903
Change-Id: Ia969e8b5bf5ac4071a00722de9d5e4d856d8071a
Reviewed-on: https://team-review.git.corp.google.com/c/399777
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: Julie Qiu <julieqiu@google.com>
Reviewed-on: https://go-review.googlesource.com/c/159218
Reviewed-by: Julie Qiu <julie@golang.org>
This is a more conservative version of the reverted CL 99135 (which
was reverted in CL 137716)
The net/url part rejects URLs with ASCII CTLs from being parsed and
the net/http part rejects writing them if a bogus url.URL is
constructed otherwise.
Updates #27302
Updates #22907
Change-Id: I09a2212eb74c63db575223277aec363c55421ed8
Reviewed-on: https://go-review.googlesource.com/c/159157
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
I needed Go 1.10 to debug and fix a test failure on that Go version in
x/tools, but I forgot what the magic 'go get' command for this was.
Googling "download specific golang version" and similar keywords showed
no results, presumably because the golang.org/dl subrepo isn't
prominently recommended nor documented anywhere.
The most appropriate documentation page to add this to is doc/install,
since it goes into some detail and is well indexed. We only need a short
section to introduce the trick.
The example does mention a specific version, Go 1.10.7, but I couldn't
imagine a way to make it version-agnostic while still being clear on
what the commands effectively do.
Change-Id: I13158564d76d95caec412cdb35a50a4356df5863
Reviewed-on: https://go-review.googlesource.com/c/157457
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
They can't be used, so we don't need code generated for them. We just
need to report errors in their bodies.
This is the minimal CL for 1.12. For 1.13, CL 158845 will remove
a bunch of special cases sprinkled about the compiler to handle "_"
functions, which should (after this CL) be unnecessary.
Update #29870
Change-Id: Iaa1c194bd0017dffdce86589fe2d36726ee83c13
Reviewed-on: https://go-review.googlesource.com/c/158820
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
ConstantTimeCompare is fairly useless if you can't rely on it being zero
when the slices are different, but thankfully it has that property
thanks to the final ConstantTimeByteEq.
Change-Id: Id51100ed7d8237abbbb15778a259065b162a48ad
Reviewed-on: https://go-review.googlesource.com/c/158643
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
This CL attempts to restore the clarity of the original specification
at https://golang.org/s/generatedcode that the line may appear
anywhere. It is preferable (for human readability), and most common
for it to be early in the file, but that is merely a convention, not
a strict well-specified requirement. Document it as so.
Background
Issue #13560 was a proposal define a standard for marking files as
generated, one that is suitable to be recognized both by humans
and machine tools. It was accepted, and the final specification
was documented at https://golang.org/s/generatedcode. Its text,
copied exactly:
Generated files are marked by a line of text that matches
the regular expression, in Go syntax:
^// Code generated .* DO NOT EDIT\.$
The .* means the tool can put whatever folderol it wants in there,
but the comment must be a single line and must start with Code generated
and end with DO NOT EDIT., with a period.
The text may appear anywhere in the file.
The https://golang.org/s/generatedcode link points to a comment
in a very large GitHub issue. That makes it harder to find.
Issue #25433 was opened about moving that information somewhere else.
It was resolved via CL 118756, which added text to cmd/go documentation
at https://golang.org/cmd/go/#hdr-Generate_Go_files_by_processing_source:
To convey to humans and machine tools that code is generated,
generated source should have a line early in the file that
matches the following regular expression (in Go syntax):
^// Code generated .* DO NOT EDIT\.$
The CL description noted that "This change merely moves that
information to a more visible place." The intention was to preserve
the specification unmodified.
The original specification was very clear that "The text may appear
anywhere in the file." The new text in cmd/go documentation wasn't
very clear. "A line early in the file" is not a precise enough criteria
to be recognized by a machine tool, because there isn't a precise
definition of what lines are "early in the file".
Updates #13560
Updates #25433
Updates #28089
Change-Id: I4e374163b16c3f972f9591ec2647fd3d5a2dd5ae
Reviewed-on: https://go-review.googlesource.com/c/158817
Reviewed-by: Rob Pike <r@golang.org>
The existing docs only mention that it is possible to change the output
destination of PrintDefaults from the default of standard error, but fail to
mention how to actually do so. This change fixes this lack by directing users
to CommandLine.SetOutput.
Fixes#15024
Change-Id: Ieaa7edbebd23d4ea6fa7e53d97a87143d590bdb3
Reviewed-on: https://go-review.googlesource.com/c/145203
Reviewed-by: Rob Pike <r@golang.org>
This is about a minor change but worthy of note because this
may affect the profile results users will see.
Change-Id: Ie2c4358b248f868662dbc71db587576481aa7238
Reviewed-on: https://go-review.googlesource.com/c/158577
Reviewed-by: Raul Silvera <rauls5382@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
Renamed from github user to use my real name in CONTRIBUTORS, added my name
to AUTHORS.
Change-Id: I671638f1525d44bcc2b0a08d0dcff6adb1717510
GitHub-Last-Rev: b989e185de
GitHub-Pull-Request: golang/go#29823
Reviewed-on: https://go-review.googlesource.com/c/158540
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Remove an unnecessary check on the heap sampling code that forced sampling
of all heap allocations larger than the sampling rate. This need to follow
a poisson process so that they can be correctly unsampled. Maintain a check
for MemProfileRate==1 to provide a mechanism for full sampling, as
documented in https://golang.org/pkg/runtime/#pkg-variables.
Additional testing for this change is on cl/129117.
Fixes#26618
Change-Id: I7802bde2afc655cf42cffac34af9bafeb3361957
GitHub-Last-Rev: 471f747af8
GitHub-Pull-Request: golang/go#29791
Reviewed-on: https://go-review.googlesource.com/c/158337
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
As a result of changes earlier in Go 1.12, the scavenger became much
more aggressive. In particular, when scavenged and unscavenged spans
coalesced, they would always become scavenged. This resulted in most
spans becoming scavenged over time. While this is good for keeping the
RSS of the program low, it also causes many more undue page faults and
many more calls to madvise.
For most applications, the impact of this was negligible. But for
applications that repeatedly grow and shrink the heap by large amounts,
the overhead can be significant. The overhead was especially obvious on
older versions of Linux where MADV_FREE isn't available and
MADV_DONTNEED must be used.
This change makes it so that scavenged spans will never coalesce with
unscavenged spans. This results in fewer page faults overall. Aside
from this, the expected impact of this change is more heap growths on
average, as span allocations will be less likely to be fulfilled. To
mitigate this slightly, this change also coalesces spans eagerly after
scavenging, to at least ensure that all scavenged spans and all
unscavenged spans are coalesced with each other.
Also, this change adds additional logic in the case where two adjacent
spans cannot coalesce. In this case, on platforms where the physical
page size is larger than the runtime's page size, we realign the
boundary between the two adjacent spans to a physical page boundary. The
advantage of this approach is that "unscavengable" spans, that is, spans
which cannot be scavenged because they don't cover at least a single
physical page are grown to a size where they have a higher likelihood of
being discovered by the runtime's scavenging mechanisms when they border
a scavenged span. This helps prevent the runtime from accruing pockets
of "unscavengable" memory in between scavenged spans, preventing them
from coalescing.
We specifically choose to apply this logic to all spans because it
simplifies the code, even though it isn't strictly necessary. The
expectation is that this change will result in a slight loss in
performance on platforms where the physical page size is larger than the
runtime page size.
Update #14045.
Change-Id: I64fd43eac1d6de6f51d7a2ecb72670f10bb12589
Reviewed-on: https://go-review.googlesource.com/c/158078
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Currently the code surrounding coalescing is duplicated between merging
with the span before the span considered for coalescing and merging with
the span after. This change factors out the shared portions of these
codepaths into a local closure which acts as a helper.
Change-Id: I7919fbed3f9a833eafb324a21a4beaa81f2eaa91
Reviewed-on: https://go-review.googlesource.com/c/158077
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The coalescing process is complex and in a follow-up change we'll need
to do it in more than one place, so this change factors out the
coalescing code in freeSpanLocked into a method on mheap.
Change-Id: Ia266b6cb1157c1b8d3d8a4287b42fbcc032bbf3a
Reviewed-on: https://go-review.googlesource.com/c/157838
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
The ABI changes should be completely transparent to Go code, but could
cause linking issues in certain situations involving assembly code
reaching across package boundaries. If users encounter linking
problems, point them to the "Compatibility" section of the ABI design
document, which gives some guidance.
Change-Id: I4156d164562e2ec0de7ae8f9a3631a32ec45b317
Reviewed-on: https://go-review.googlesource.com/c/158237
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
On aix/ppc64, if the server closes before the client calls Accept,
this test will fail.
Increasing the time before the server closes should resolve this
timeout.
Updates #29685
Change-Id: Iebb849d694fc9c37cf216ce1f0b8741249b98016
Reviewed-on: https://go-review.googlesource.com/c/158038
Reviewed-by: Ian Lance Taylor <iant@golang.org>
