The current generator is a simple LSFR, which showed strong
correlation in higher bits, as manifested by fastrandn().
Change it with xorshift64+, which is slightly more complex,
has a larger state, but has a period of 2^64-1 and is much better
at statistical tests. The version used here is capable of
passing Diehard and even SmallCrush.
Speed is slightly worse but is probably insignificant:
name old time/op new time/op delta
Fastrand-4 0.77ns ±12% 0.91ns ±21% +17.31% (p=0.048 n=5+5)
FastrandHashiter-4 13.6ns ±21% 15.2ns ±17% ~ (p=0.160 n=6+5)
Fastrandn/2-4 2.30ns ± 5% 2.45ns ±15% ~ (p=0.222 n=5+5)
Fastrandn/3-4 2.36ns ± 7% 2.45ns ± 6% ~ (p=0.222 n=5+5)
Fastrandn/4-4 2.33ns ± 8% 2.61ns ±30% ~ (p=0.126 n=6+5)
Fastrandn/5-4 2.33ns ± 5% 2.48ns ± 9% ~ (p=0.052 n=6+5)
Fixes#21806
Change-Id: I013bb37b463fdfc229a7f324df8fe2da8d286f33
Reviewed-on: https://go-review.googlesource.com/62530
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Return early from deltimer, with false as the result,
to indicate that we couldn't delete the timer since its
timersBucket was nil(not set) in the first place.
That happens in such a case where a user created
the timer from a Ticker with:
t := time.Ticker{C: c}
The above usage skips the entire setup of assigning
the appropriate underlying runtimeTimer and timersBucket,
steps that are done for us by time.NewTicker.
CL 34784 introduced this bug with an optimization, by changing
stopTimer to retrieve the timersBucket from the timer itself
(which is unset with the mentioned usage pattern above),
whereas the old behavior relied on indexing
by goroutine ID into the global slice of runtime
timers, to retrieve the appropriate timersBucket.
Fixes#21874
Change-Id: Ie9ccc6bdee685414b2430dc4aa74ef618cea2b33
Reviewed-on: https://go-review.googlesource.com/63970
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change has no real effect in itself. This is to prepare for a
followup change that will call lockOSThread during a cgo callback when
there is no p assigned, and therefore when lockOSThread can not use a
write barrier.
Change-Id: Ia122d41acf54191864bcb68f393f2ed3b2f87abc
Reviewed-on: https://go-review.googlesource.com/63630
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Move it from the runtime package, as we will soon add more packages and
functions for it to check.
The test used the testEnv func, which cleaned certain environment
variables from a command, so it was moved to internal/testenv under a
more descriptive (and less ambiguous) name. Add a simple godoc to it
too.
For #21851.
Change-Id: I6f39c1f23b45377718355fafe66ffd87047d8ab6
Reviewed-on: https://go-review.googlesource.com/63550
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
This makes it easier to deduce from the field names which overflow
field corresponds to h.buckets and which to h.oldbuckets by aligning
the naming with the buckets fields in hmap.
Change-Id: I8d6a729229a190db0212bac012ead1a3c13cf5d0
Reviewed-on: https://go-review.googlesource.com/62411
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Move the check near the code in evacuate that relies on
the relation evacuateX+1 == evacuateY.
If the relation is fullfilled the check is known to be true
at compile time and removed by the compiler.
Change-Id: I711b75e09047bf347819ccaeec41d244a5883867
Reviewed-on: https://go-review.googlesource.com/62410
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
After the number of lost extra events are written to the the cpuprof log,
the number of lost extra events should be set to zero, or else, the next
time time addExtra is logged, lostExtra will be overcounted. This change
resets lostExtra after its value is written to the log.
Fixes#21836
Change-Id: I8a6ac9c61e579e7a5ca7bdb0f3463f8ae8b9f863
Reviewed-on: https://go-review.googlesource.com/63270
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
While some map literals were marked non-escaping that information
was lost when creating the corresponding OMAKE node which made map
literals always heap allocated.
Copying the escape information to the corresponding OMAKE node allows
stack allocation of hmap and a map bucket for non escaping map literals.
Fixes#21830
Change-Id: Ife0b020fffbc513f1ac009352f2ecb110d6889c9
Reviewed-on: https://go-review.googlesource.com/62790
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
1. remove broken verification
The runtime check assumes that no-pcln symbol entry have zero value,
but the linker emit no entries if the symbol is no-pcln.
As a result, if there are no-pcln symbols at the very end of pcln
table, it will panic.
2. correct condition of export
Handle special chracters in pluginpath correcty.
Export "go.itab.*", so different plugins can share the same itab.
Fixes#18190
Change-Id: Ia4f9c51d83ce8488a9470520f1ee9432802cfc1d
Reviewed-on: https://go-review.googlesource.com/61091
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Along the way, track bad modules. Make sure they don't end up on
the active modules list, and aren't accidentally reprocessed as
new plugins.
Fixes#19004
Change-Id: I8a5e7bb11f572f7b657a97d521a7f84822a35c07
Reviewed-on: https://go-review.googlesource.com/61171
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
runtime.makemap will allocate map buckets on the heap for hints larger
than the number of elements a single map bucket can hold.
Do not allocate any map bucket on the stack if it is known at compile time
that hint is larger than the number of elements one map bucket can hold.
This avoids zeroing and reserving memory on the stack that will not be used.
Change-Id: I1a5ab853fb16f6a18d67674a77701bf0cf29b550
Reviewed-on: https://go-review.googlesource.com/60450
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The compiler and reflect already zero hiter before mapiterinit.
While here expand the documentation for mapiterinit.
Change-Id: I78b05d4d14bf78e8091e5353cdac80ffed30ca1e
Reviewed-on: https://go-review.googlesource.com/60673
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Remove the runtime ismapkey check from makemap and
add a check that the map key type supports comparison
to the hmap construction in the compiler.
Move the ismapkey check for the reflect code path
into reflect_makemap.
Change-Id: I718f79b0670c05b63ef31721e72408f59ec4ae86
Reviewed-on: https://go-review.googlesource.com/61035
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Move memclr to a separate file to make it consistent
with other platforms asm function to file organization.
Remove nacl from the memmove filename as the implementation
is generic for the amd64p32 platform even if currently only
nacl is supported for amd64p32.
Change-Id: I8930b76da430a5cf2664801974e4f5185fc0f82f
Reviewed-on: https://go-review.googlesource.com/61031
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
overLoadFactor wasn't really doing what it says it does.
It was reporting overOrEqualToLoadFactor. That's actually what we
want when adding an entry to a map, but it isn't what we want when
constructing a map in the first place.
The impetus for this change is that if you make a map with a hint
of exactly 8 (which happens, for example, with the unitMap in
time/format.go), we allocate 2 buckets for it instead of 1.
Instead, make overLoadFactor really report when it is > the max
allowed load factor, not >=. Adjust the callers who want to ensure
that the map is no more than the max load factor after an insertion
by adding a +1 to the current (pre-addition) size.
Change-Id: Ie8d85344800a9a870036b637b1031ddd9e4b93f9
Reviewed-on: https://go-review.googlesource.com/61053
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Matches other architectures by using names for syscalls instead of
numbers directly.
Fixes#20499.
Change-Id: I63d606b0b1fe6fb517fd994a7542a3f38d80dd54
Reviewed-on: https://go-review.googlesource.com/44213
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Between go1.7 and go1.8, a performance regression was introduced in some of the
BenchmarkCompareBytes benchmarks.
Go1.7 vs Go1.8:
BenchmarkCompareBytesToNil-8 7.44 8.44 +13.44%
BenchmarkCompareBytesIdentical-8 6.96 11.5 +65.23%
BenchmarkCompareBytesBigIdentical-8 6.65 47112 +708351.13%
This change fixes the problem by optimizing the case where the byte slices being
compared are equal:
Go1.9 vs current:
BenchmarkCompareBytesToNil-8 7.35 7.00 -4.76%
BenchmarkCompareBytesIdentical-8 11.4 6.81 -40.26%
BenchmarkCompareBytesBigIdentical-8 48396 9.26 -99.98%
runtime.cmpstring can benefit from the same approach and is also changed.
Change-Id: I3cb25f59d8b940a83a2cf687eea764cfeff90688
Reviewed-on: https://go-review.googlesource.com/59650
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This change implements the convention for generated code header agreed upon in https://golang.org/s/generatedcode.
Additionally run go generate.
Also update some comments.
Updates #13560
Change-Id: If45f91b93aaa0d43280c2c4630823bc4d2dc7d3a
Reviewed-on: https://go-review.googlesource.com/60250
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Check map invariants, type size and alignments during compile time.
Keep runtime checks for reflect by adding them to reflect_makemap.
Change-Id: Ia28610626591bf7fafb7d5a1ca318da272e54879
Reviewed-on: https://go-review.googlesource.com/59914
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Right now we only kind of sort of trace GC STW events. We emit events
around mark termination, but those start well after stopping the world
and end before starting it again, and we don't emit any events for
sweep termination.
Fix this by generalizing EvGCScanStart/EvGCScanDone. These were
already re-purposed to indicate mark termination (despite the names).
This commit renames them to EvGCSTWStart/EvGCSTWDone, adds an argument
to indicate the STW reason, and shuffles the runtime to generate them
right before stopping the world and right after starting the world,
respectively.
These events will make it possible to generate precise minimum mutator
utilization (MMU) graphs and could be useful in detecting
non-preemptible goroutines (e.g., #20792).
Change-Id: If95783f370781d8ef66addd94886028103a7c26f
Reviewed-on: https://go-review.googlesource.com/55411
Reviewed-by: Rick Hudson <rlh@golang.org>
Found with mvdan.cc/unindent. It skipped the cases where parentheses
would need to be added, where comments would have to be moved elsewhere,
or where actions and simple logic would mix.
One of them was of the form "err != nil && err == io.EOF", so the first
part was removed.
Change-Id: Ie504c2b03a2c87d10ecbca1b9270069be1171b91
Reviewed-on: https://go-review.googlesource.com/57690
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
CL 57291 broke on solaris because it depends on signal forwarding
working for signals raised by dieFromSignal.
Call sigtrampgo instead of sighandler directly, like the other
unix platforms.
Fixes the solaris builders.
Change-Id: I6bf314c436d1edeaecc4b03f15a9155270919524
Reviewed-on: https://go-review.googlesource.com/59811
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit adds an example to the runtime/trace package
on how to use the trace.Start and trace.Stop functions
to trace the execution of a Go program and write
its trace output to a file.
Change-Id: Idf920398f1c3b9d185af9df5ce9293f2361db022
Reviewed-on: https://go-review.googlesource.com/51170
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This change could improve the hit rate on itabTable during growth.
While we are here patch comments to refer to existing functions.
Change-Id: I76f81c860a3d6107e077e7e3932550858a8b7651
Reviewed-on: https://go-review.googlesource.com/55912
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
CL 49590 made it possible for external signal handlers to catch
signals from a crashing Go process. This CL extends that support
to handlers registered after the Go runtime has initialized.
Updates #20392 (and possibly fix it).
Change-Id: I18eccd5e958a505f4d1782a7fc51c16bd3a4ff9c
Reviewed-on: https://go-review.googlesource.com/57291
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
All of the mapfast key types are reflexive.
Change-Id: I8595aed2a9d945cda1b5d08e2067dce0f1c0d585
Reviewed-on: https://go-review.googlesource.com/59132
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
The newly added routines are exact copies of the generic routines,
except for the function names and that growWork_fastX calls evacuate_fastX.
Actual optimization will happen in subsequent CLs.
This is intended to ease reviewing.
Change-Id: I52ef7dd40b2bdfc9cba2496544c0604e6e71cf7f
Reviewed-on: https://go-review.googlesource.com/59130
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Went mainly for the ones that make no sense, such as the ones
mid-sentence or after commas.
Change-Id: Ie245d2c19cc7428a06295635cf6a9482ade25ff0
Reviewed-on: https://go-review.googlesource.com/57293
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Prior to this change, we use typedmemmove to write the key
value to its new location in mapassign_fast32 and mapassign_fast64.
(The use of typedmemmove was a last-minute fix in the 1.9 cycle;
see #21297 and CL 53414.)
This is significantly less inefficient than direct assignment or
calling writebarrierptr directly.
Fortunately, there aren't many cases to consider.
On systems with 32 bit pointers:
* A 32 bit AMEM value either is a single pointer or has no pointers.
* A 64 bit AMEM value may contain a pointer at the beginning,
a pointer at 32 bits, or two pointers.
On systems with 64 bit pointers:
* A 32 bit AMEM value contains no pointers.
* A 64 bit AMEM value either is a single pointer or has no pointers.
All combinations except the 32 bit pointers / 64 bit AMEM value are
cheap and easy to handle, and the problematic case is likely rare.
The most popular map keys appear to be ints and pointers.
So we handle them exhaustively. The sys.PtrSize checks are constant branches
and are eliminated by the compiler.
An alternative fix would be to return a pointer to the key,
and have the calling code do the assignment, at which point the compiler
would have full type information.
Initial tests suggest that the performance difference between these
strategies is negligible, and this fix is considerably simpler,
and has much less impact on binary size.
Fixes#21321
Change-Id: Ib03200e89e2324dd3c76d041131447df66f22bfe
Reviewed-on: https://go-review.googlesource.com/59110
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CL 36428 changed the way nanotime works so on Darwin and Windows it
now depends on runtime.startNano, which is computed at runtime.init
time. Unfortunately, the `runtimeInitTime = nanotime()` initialization
happened *before* runtime.init, so on these platforms runtimeInitTime
is set incorrectly. The one (and only) consequence of this is that the
start time printed in gctrace lines is bogus:
gc 1 18446653480.186s 0%: 0.092+0.47+0.038 ms clock, 0.37+0.15/0.81/1.8+0.15 ms cpu, 4->4->1 MB, 5 MB goal, 8 P
To fix this, this commit moves the runtimeInitTime initialization to
shortly after runtime.init, at which point nanotime is safe to use.
This also requires changing the condition in newproc1 that currently
uses runtimeInitTime != 0 simply to detect whether or not the main M
has started. Since runtimeInitTime could genuinely be 0 now, this
introduces a separate flag to newproc1.
Fixes#21554.
Change-Id: Id874a4b912d3fa3d22f58d01b31ffb3548266d3b
Reviewed-on: https://go-review.googlesource.com/58690
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This eliminates a nil check of b while evaluating b.tophash,
which is in the inner loop of many hot map functions.
It also makes the code a bit clearer.
Also remove some gotos in favor of labeled breaks.
On non-x86 architectures, this change introduces a pointless reg-reg move,
although the cause is well-understood (#21572).
Change-Id: Ib7ee58b59ea5463b92e1590c8b8f5c0ef87d410a
Reviewed-on: https://go-review.googlesource.com/58372
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
This is a crude compiler pass to eliminate stores to auto variables
that are only ever written to.
Eliminates an unnecessary store to x from the following code:
func f() int {
var x := 1
return *(&x)
}
Fixes#19765.
Change-Id: If2c63a8ae67b8c590b6e0cc98a9610939a3eeffa
Reviewed-on: https://go-review.googlesource.com/38746
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
On 386 the below code triggered an infinite loop in growslice:
x = make([]byte, 1<<30-1, 1<<30-1)
x = append(x, x...)
Check for overflow when calculating the new slice capacity
and set the new capacity to the requested capacity when an overflow
is detected to avoid an infinite loop.
No automatic test added due to requiring to allocate 1GB of memory
on a 32bit plaform before use of append is able to trigger the
overflow check.
Fixes#21441
Change-Id: Ia871cc9f88479dacf2c7044531b233f83d2fcedf
Reviewed-on: https://go-review.googlesource.com/57950
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
