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59 Commits

Author SHA1 Message Date
Austin Clements
c85b12b579 runtime: make LockOSThread/UnlockOSThread nested
Currently, there is a single bit for LockOSThread, so two calls to
LockOSThread followed by one call to UnlockOSThread will unlock the
thread. There's evidence (#20458) that this is almost never what
people want or expect and it makes these APIs very hard to use
correctly or reliably.

Change this so LockOSThread/UnlockOSThread can be nested and the
calling goroutine will not be unwired until UnlockOSThread has been
called as many times as LockOSThread has. This should fix the vast
majority of incorrect uses while having no effect on the vast majority
of correct uses.

Fixes #20458.

Change-Id: I1464e5e9a0ea4208fbb83638ee9847f929a2bacb
Reviewed-on: https://go-review.googlesource.com/45752
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-10-05 19:50:23 +00:00
Keith Randall
dbe3522c7f runtime: fix hashmap load factor computation
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>
2017-09-02 05:44:23 +00:00
Martin Möhrmann
2a56b023af runtime: specialize memhash32 and memhash64
AMD64 with AES support disabled:
name                old time/op    new time/op    delta
MapPopulate/1         78.0ns ± 1%    75.5ns ± 1%   -3.17%  (p=0.000 n=10+9)
MapPopulate/10         764ns ± 2%     673ns ± 2%  -11.91%  (p=0.000 n=10+10)
MapPopulate/100       9.52µs ± 1%    8.54µs ± 1%  -10.37%  (p=0.000 n=8+10)
MapPopulate/1000       116µs ± 2%     103µs ± 1%  -10.40%  (p=0.000 n=10+8)
MapPopulate/10000     1.01ms ± 1%    0.90ms ± 1%  -10.70%  (p=0.000 n=10+10)
MapPopulate/100000    9.81ms ± 1%    8.67ms ± 2%  -11.54%  (p=0.000 n=10+10)

386 with AES support disabled:
name                old time/op    new time/op    delta
MapPopulate/1         95.3ns ± 1%    90.6ns ± 1%  -4.95%  (p=0.000 n=10+9)
MapPopulate/10         983ns ± 2%     912ns ± 1%  -7.18%  (p=0.000 n=10+10)
MapPopulate/100       11.9µs ± 2%    11.2µs ± 1%  -6.01%  (p=0.000 n=10+10)
MapPopulate/1000       140µs ± 1%     131µs ± 1%  -6.19%  (p=0.000 n=10+10)
MapPopulate/10000     1.26ms ± 2%    1.18ms ± 1%  -5.93%  (p=0.000 n=9+10)
MapPopulate/100000    12.1ms ± 2%    11.4ms ± 1%  -5.48%  (p=0.000 n=10+10)

Fixes #21539

Change-Id: Ice128c947c9a6a294800d6a5250d82045eb70b55
Reviewed-on: https://go-review.googlesource.com/59352
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-08-28 19:55:27 +00:00
Austin Clements
80832974ac runtime: make rwmutex work on Ms instead of Gs
Currently runtime.rwmutex is written to block the calling goroutine
rather than the calling thread. However, rwmutex was intended to be
used in the scheduler, which means it needs to be a thread-level
synchronization primitive.

Hence, this modifies rwmutex to synchronize threads instead of
goroutines. This has the consequence of making it write-barrier-free,
which is also important for using it in the scheduler.

The implementation makes three changes: it replaces the "w" semaphore
with a mutex, since this was all it was being used for anyway; it
replaces "writerSem" with a single pending M that parks on its note;
and it replaces "readerSem" with a list of Ms that park on their notes
plus a pass count that together emulate a counting semaphore. I
model-checked the safety and liveness of this implementation through
>1 billion schedules.

For #20738.

Change-Id: I3cf5a18c266a96a3f38165083812803510217787
Reviewed-on: https://go-review.googlesource.com/47071
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-28 22:08:57 +00:00
Ian Lance Taylor
09ebbf4085 runtime: add read/write mutex type
This is a runtime version of sync.RWMutex that can be used by code in
the runtime package. The type is not quite the same, in that the zero
value is not valid.

For future use by CL 43713.

Updates #19546

Change-Id: I431eb3688add16ce1274dab97285f555b72735bf
Reviewed-on: https://go-review.googlesource.com/45991
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-06-19 17:40:38 +00:00
Austin Clements
1a033b1a70 runtime: separate spans of noscan objects
Currently, we mix objects with pointers and objects without pointers
("noscan" objects) together in memory. As a result, for every object
we grey, we have to check that object's heap bits to find out if it's
noscan, which adds to the per-object cost of GC. This also hurts the
TLB footprint of the garbage collector because it decreases the
density of scannable objects at the page level.

This commit improves the situation by using separate spans for noscan
objects. This will allow a much simpler noscan check (in a follow up
CL), eliminate the need to clear the bitmap of noscan objects (in a
follow up CL), and improves TLB footprint by increasing the density of
scannable objects.

This is also a step toward eliminating dead bits, since the current
noscan check depends on checking the dead bit of the first word.

This has no effect on the heap size of the garbage benchmark.

We'll measure the performance change of this after the follow-up
optimizations.

This is a cherry-pick from dev.garbage commit d491e550c3. The only
non-trivial merge conflict was in updatememstats in mstats.go, where
we now have to separate the per-spanclass stats from the per-sizeclass
stats.

Change-Id: I13bdc4869538ece5649a8d2a41c6605371618e40
Reviewed-on: https://go-review.googlesource.com/41251
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-04-28 22:50:31 +00:00
Austin Clements
13ae271d5d runtime: introduce a type for lfstacks
The lfstack API is still a C-style API: lfstacks all have unhelpful
type uint64 and the APIs are package-level functions. Make the code
more readable and Go-style by creating an lfstack type with methods
for push, pop, and empty.

Change-Id: I64685fa3be0e82ae2d1a782a452a50974440a827
Reviewed-on: https://go-review.googlesource.com/38290
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-03-19 22:42:24 +00:00
Austin Clements
4b8f41daa6 runtime: print user stack on other threads during GOTRACBEACK=crash
Currently, when printing tracebacks of other threads during
GOTRACEBACK=crash, if the thread is on the system stack we print only
the header for the user goroutine and fail to print its stack. This
happens because we passed the g0 to traceback instead of curg. The g0
never has anything set in its gobuf, so traceback doesn't print
anything.

Fix this by passing _g_.m.curg to traceback instead of the g0.

Fixes #19494.

Change-Id: Idfabf94d6a725e9cdf94a3923dead6455ef3b217
Reviewed-on: https://go-review.googlesource.com/38012
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-15 22:16:12 +00:00
Austin Clements
4a7cf960c3 runtime: make ReadMemStats STW for < 25µs
Currently ReadMemStats stops the world for ~1.7 ms/GB of heap because
it collects statistics from every single span. For large heaps, this
can be quite costly. This is particularly unfortunate because many
production infrastructures call this function regularly to collect and
report statistics.

Fix this by tracking the necessary cumulative statistics in the
mcaches. ReadMemStats still has to stop the world to stabilize these
statistics, but there are only O(GOMAXPROCS) mcaches to collect
statistics from, so this pause is only 25µs even at GOMAXPROCS=100.

Fixes #13613.

Change-Id: I3c0a4e14833f4760dab675efc1916e73b4c0032a
Reviewed-on: https://go-review.googlesource.com/34937
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-03-04 02:56:37 +00:00
Russ Cox
b788fd80e6 runtime: new profile buffer implementation supporting label pointers
The existing CPU profiling buffer is a slice of uintptr, but we want to
start including profiling label data in the profiles, and those labels need
to be pointers in order to let them describe rich information.

This CL implements a new profBuf type that holds both a slice of uint64
for data and a slice of unsafe.Pointer for profiling labels (aka tags).
Making the runtime use these buffers will happen in followup CLs.

Change-Id: I9ff16b532d8edaf4ce0cbba1098229a561834efc
Reviewed-on: https://go-review.googlesource.com/36713
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-02-23 19:47:23 +00:00
Josh Bleecher Snyder
46a75870ad runtime: speed up fastrand() % n
This occurs a fair amount in the runtime for non-power-of-two n.
Use an alternative, faster formulation.

name           old time/op  new time/op  delta
Fastrandn/2-8  4.45ns ± 2%  2.09ns ± 3%  -53.12%  (p=0.000 n=14+14)
Fastrandn/3-8  4.78ns ±11%  2.06ns ± 2%  -56.94%  (p=0.000 n=15+15)
Fastrandn/4-8  4.76ns ± 9%  1.99ns ± 3%  -58.28%  (p=0.000 n=15+13)
Fastrandn/5-8  4.96ns ±13%  2.03ns ± 6%  -59.14%  (p=0.000 n=15+15)

name                    old time/op  new time/op  delta
SelectUncontended-8     33.7ns ± 2%  33.9ns ± 2%  +0.70%  (p=0.000 n=49+50)
SelectSyncContended-8   1.68µs ± 4%  1.65µs ± 4%  -1.54%  (p=0.000 n=50+45)
SelectAsyncContended-8   282ns ± 1%   277ns ± 1%  -1.50%  (p=0.000 n=48+43)
SelectNonblock-8        5.31ns ± 1%  5.32ns ± 1%    ~     (p=0.275 n=45+44)
SelectProdCons-8         585ns ± 3%   577ns ± 2%  -1.35%  (p=0.000 n=50+50)
GoroutineSelect-8       1.59ms ± 2%  1.59ms ± 1%    ~     (p=0.084 n=49+48)

Updates #16213

Change-Id: Ib555a4d7da2042a25c3976f76a436b536487d5b7
Reviewed-on: https://go-review.googlesource.com/36932
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-14 00:01:22 +00:00
Sokolov Yura
d03c124860 runtime: implement fastrand in go
So it could be inlined.

Using bit-tricks it could be implemented without condition
(improved trick version by Minux Ma).

Simple benchmark shows it is faster on i386 and x86_64, though
I don't know will it be faster on other architectures?

benchmark                       old ns/op     new ns/op     delta
BenchmarkFastrand-3             2.79          1.48          -46.95%
BenchmarkFastrandHashiter-3     25.9          24.9          -3.86%

Change-Id: Ie2eb6d0f598c0bb5fac7f6ad0f8b5e3eddaa361b
Reviewed-on: https://go-review.googlesource.com/34782
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-10 19:16:29 +00:00
Keith Randall
688995d1e9 cmd/compile: do more type conversion inline
The code to do the conversion is smaller than the
call to the runtime.
The 1-result asserts need to call panic if they fail, but that
code is out of line.

The only conversions left in the runtime are those which
might allocate and those which might need to generate an itab.

Given the following types:
  type E interface{}
  type I interface { foo() }
  type I2 iterface { foo(); bar() }
  type Big [10]int
  func (b Big) foo() { ... }

This CL inlines the following conversions:

was assertE2T
  var e E = ...
  b := i.(Big)
was assertE2T2
  var e E = ...
  b, ok := i.(Big)
was assertI2T
  var i I = ...
  b := i.(Big)
was assertI2T2
  var i I = ...
  b, ok := i.(Big)
was assertI2E
  var i I = ...
  e := i.(E)
was assertI2E2
  var i I = ...
  e, ok := i.(E)

These are the remaining runtime calls:

convT2E:
  var b Big = ...
  var e E = b
convT2I:
  var b Big = ...
  var i I = b
convI2I:
  var i2 I2 = ...
  var i I = i2
assertE2I:
  var e E = ...
  i := e.(I)
assertE2I2:
  var e E = ...
  i, ok := e.(I)
assertI2I:
  var i I = ...
  i2 := i.(I2)
assertI2I2:
  var i I = ...
  i2, ok := i.(I2)

Fixes #17405
Fixes #8422

Change-Id: Ida2367bf8ce3cd2c6bb599a1814f1d275afabe21
Reviewed-on: https://go-review.googlesource.com/32313
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-11-02 21:33:03 +00:00
Martin Möhrmann
d7b34d5f29 runtime: improve atoi implementation
- Adds overflow checks
- Adds parsing of negative integers
- Adds boolean return value to signal parsing errors
- Adds atoi32 for parsing of integers that fit in an int32
- Adds tests

Handling of errors to provide error messages
at the call sites is left to future CLs.

Updates #17718

Change-Id: I3cacd0ab1230b9efc5404c68edae7304d39bcbc0
Reviewed-on: https://go-review.googlesource.com/32390
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-01 14:04:39 +00:00
Austin Clements
87e48c5afd runtime, cmd/compile: rename memclr -> memclrNoHeapPointers
Since barrier-less memclr is only safe in very narrow circumstances,
this commit renames memclr to avoid accidentally calling memclr on
typed memory. This can cause subtle, non-deterministic bugs, so it's
worth some effort to prevent. In the near term, this will also prevent
bugs creeping in from any concurrent CLs that add calls to memclr; if
this happens, whichever patch hits master second will fail to compile.

This also adds the other new memclr variants to the compiler's
builtin.go to minimize the churn on that binary blob. We'll use these
in future commits.

Updates #17503.

Change-Id: I00eead049f5bd35ca107ea525966831f3d1ed9ca
Reviewed-on: https://go-review.googlesource.com/31369
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2016-10-28 18:20:33 +00:00
Austin Clements
4d6207790b runtime: consolidate h_allspans and mheap_.allspans
These are two ways to refer to the allspans array that hark back to
when the runtime was split between C and Go. Clean this up by making
mheap_.allspans a slice and eliminating h_allspans.

Change-Id: Ic9360d040cf3eb590b5dfbab0b82e8ace8525610
Reviewed-on: https://go-review.googlesource.com/30530
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2016-10-25 22:32:42 +00:00
Martin Möhrmann
252093f120 runtime: remove maxstring
Before this CL the runtime prevented printing of overlong strings with the print
function when the length of the string was determined to be corrupted.
Corruption was checked by comparing the string size against the limit
which was stored in maxstring.

However maxstring was not updated everywhere were go strings were created
e.g. for string constants during compile time. Thereby the check for maximum
string length prevented the printing of some valid strings.

The protection maxstring provided did not warrant the bookkeeping
and global synchronization needed to keep maxstring updated to the
correct limit everywhere.

Fixes #16999

Change-Id: I62cc2f4362f333f75b77f199ce1a71aac0ff7aeb
Reviewed-on: https://go-review.googlesource.com/28813
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-08 15:57:01 +00:00
Dmitry Vyukov
fcd7c02c70 runtime: fix CPU underutilization
Runqempty is a critical predicate for scheduler. If runqempty spuriously
returns true, then scheduler can fail to schedule arbitrary number of
runnable goroutines on idle Ps for arbitrary long time. With the addition
of runnext runqempty predicate become broken (can spuriously return true).
Consider that runnext is not nil and the main array is empty. Runqempty
observes that the array is empty, then it is descheduled for some time.
Then queue owner pushes another element to the queue evicting runnext
into the array. Then queue owner pops runnext. Then runqempty resumes
and observes runnext is nil and returns true. But there were no point
in time when the queue was empty.

Fix runqempty predicate to not return true spuriously.

Change-Id: Ifb7d75a699101f3ff753c4ce7c983cf08befd31e
Reviewed-on: https://go-review.googlesource.com/20858
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-03 10:06:32 +00:00
Austin Clements
61f56e925e runtime: fix pagesInUse accounting
When we grow the heap, we create a temporary "in use" span for the
memory acquired from the OS and then free that span to link it into
the heap. Hence, we (1) increase pagesInUse when we make the temporary
span so that (2) freeing the span will correctly decrease it.

However, currently step (1) increases pagesInUse by the number of
pages requested from the heap, while step (2) decreases it by the
number of pages requested from the OS (the size of the temporary
span). These aren't necessarily the same, since we round up the number
of pages we request from the OS, so steps 1 and 2 don't necessarily
cancel out like they're supposed to. Over time, this can add up and
cause pagesInUse to underflow and wrap around to 2^64. The garbage
collector computes the sweep ratio from this, so if this happens, the
sweep ratio becomes effectively infinite, causing the first allocation
on each P in a sweep cycle to sweep the entire heap. This makes
sweeping effectively STW.

Fix this by increasing pagesInUse in step 1 by the number of pages
requested from the OS, so that the two steps correctly cancel out. We
add a test that checks that the running total matches the actual state
of the heap.

Fixes #15022. For 1.6.x.

Change-Id: Iefd9d6abe37d0d447cbdbdf9941662e4f18eeffc
Reviewed-on: https://go-review.googlesource.com/21280
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2016-04-04 15:33:26 +00:00
Keith Randall
15ea61146e runtime: use unaligned loads on ppc64
benchmark                      old ns/op     new ns/op     delta
BenchmarkAlignedLoad-160       8.67          7.42          -14.42%
BenchmarkUnalignedLoad-160     8.63          7.37          -14.60%

Change-Id: Id4609d7b4038c4d2ec332efc4fe6f1adfb61b82b
Reviewed-on: https://go-review.googlesource.com/20812
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-18 19:21:53 +00:00
Emmanuel Odeke
6dfcc336c5 runtime: move testSchedLocalQueue* to export_test
Move functions testSchedLocalQueueLocal and testSchedLocalQueueSteal
from proc.go to export_test.go, the only site that they are used.

Fixes #14796

Change-Id: I16b6fa4a13835eab33f66a2c2e87a5f5c79b7bd3
Reviewed-on: https://go-review.googlesource.com/20640
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-13 00:34:58 +00:00
Brad Fitzpatrick
519474451a all: make copyright headers consistent with one space after period
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.

Go policy has been single space after periods in comments for some time.

The copyright header template at:

    https://golang.org/doc/contribute.html#copyright

also uses a single space.

Make them all consistent.

Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-01 23:34:33 +00:00
Austin Clements
8847a5913a runtime: remove unused parfor code
Change-Id: Ibbfae20cab48163f22d661604ef730705f2b97ba
Reviewed-on: https://go-review.googlesource.com/19661
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-02-21 23:22:11 +00:00
Ian Lance Taylor
cc0a04d351 runtime: fix errno sign for some mmap and mincore cases
The caller of mmap expects it to return a positive errno value, but the
linux-arm64 and nacl-386 system calls returned a negative errno value.
Correct them to negate the errno value.

The caller of mincore expects it to return a negative errno value (yes,
this is inconsistent), but the linux-mips64x and linux-ppc64x system
call returned a positive errno value.  Correct them to negate the errno
value.

Add a test that mmap returns errno with the correct sign.  Brad added a
test for mincore's errno value in https://golang.org/cl/19457.

Fixes #14297.

Change-Id: I2b93f32e679bd1eae1c9aef9ae7bcf0ba39521b5
Reviewed-on: https://go-review.googlesource.com/19455
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-02-12 00:07:29 +00:00
Brad Fitzpatrick
70418eb819 runtime: add test for mincore's return value sign on Linux
Updates #14297

Change-Id: I6b5f5020af5efaaa71280bdeb2ff99785ee9b959
Reviewed-on: https://go-review.googlesource.com/19457
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-02-11 19:09:50 +00:00
Austin Clements
1556c317f1 runtime: use at least "system" traceback level for runtime tests
While the default behavior of eliding runtime frames from tracebacks
usually makes sense, this is not the case when you're trying to test
the runtime itself. Fix this by forcing the traceback level to at
least "system" in the runtime tests.

This will specifically help with debugging issue #13645, which has
proven remarkably resistant to reproduction outside of the build
dashboard itself.

Change-Id: I2a8356ba6c3c5badba8bb3330fc527357ec0d296
Reviewed-on: https://go-review.googlesource.com/18648
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
2016-01-15 02:22:46 +00:00
Michael Matloob
432cb66f16 runtime: break out system-specific constants into package sys
runtime/internal/sys will hold system-, architecture- and config-
specific constants.

Updates #11647

Change-Id: I6db29c312556087a42e8d2bdd9af40d157c56b54
Reviewed-on: https://go-review.googlesource.com/16817
Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-12 17:04:45 +00:00
Michael Matloob
67faca7d9c runtime: break atomics out into package runtime/internal/atomic
This change breaks out most of the atomics functions in the runtime
into package runtime/internal/atomic. It adds some basic support
in the toolchain for runtime packages, and also modifies linux/arm
atomics to remove the dependency on the runtime's mutex. The mutexes
have been replaced with spinlocks.

all trybots are happy!
In addition to the trybots, I've tested on the darwin/arm64 builder,
on the darwin/arm builder, and on a ppc64le machine.

Change-Id: I6698c8e3cf3834f55ce5824059f44d00dc8e3c2f
Reviewed-on: https://go-review.googlesource.com/14204
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-10 17:38:04 +00:00
Matthew Dempsky
84afa1be76 runtime: make iface/eface handling more type safe
Change compiler-invoked interface functions to directly take
iface/eface parameters instead of fInterface/interface{} to avoid
needing to always convert.

For the handful of functions that legitimately need to take an
interface{} parameter, add efaceOf to type-safely convert *interface{}
to *eface.

Change-Id: I8928761a12fd3c771394f36adf93d3006a9fcf39
Reviewed-on: https://go-review.googlesource.com/16166
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-10-21 23:08:22 +00:00
Ian Lance Taylor
2961cab965 runtime: remove _Kind constants
The duplication of _Kind and kind constants is a legacy of the
conversion from C.

Change-Id: I368b35a41f215cf91ac4b09dac59699edb414a0e
Reviewed-on: https://go-review.googlesource.com/15800
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-10-13 00:15:36 +00:00
Raul Silvera
27ee719fb3 pprof: improve sampling for heap profiling
The current heap sampling introduces some bias that interferes
with unsampling, producing unexpected heap profiles.
The solution is to use a Poisson process to generate the
sampling points, using the formulas described at
https://en.wikipedia.org/wiki/Poisson_process

This fixes #12620

Change-Id: If2400809ed3c41de504dd6cff06be14e476ff96c
Reviewed-on: https://go-review.googlesource.com/14590
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-10-05 08:15:09 +00:00
Austin Clements
e01be84149 runtime: test that periodic GC works
We've broken periodic GC a few times without noticing because there's
no test for it, partly because you have to wait two minutes to see if
it happens. This exposes control of the periodic GC timeout to runtime
tests and adds a test that cranks it down to zero and sleeps for a bit
to make sure periodic GCs happen.

Change-Id: I3ec44e967e99f4eda752f85c329eebd18b87709e
Reviewed-on: https://go-review.googlesource.com/13169
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
2015-09-30 19:24:07 +00:00
Austin Clements
05a3b1fce5 cmd/compile: fix uninitialized memory in compare of interface value
A comparison of the form l == r where l is an interface and r is
concrete performs a type assertion on l to convert it to r's type.
However, the compiler fails to zero the temporary where the result of
the type assertion is written, so if the type is a pointer type and a
stack scan occurs while in the type assertion, it may see an invalid
pointer on the stack.

Fix this by zeroing the temporary. This is equivalent to the fix for
type switches from c4092ac.

Fixes #12253.

Change-Id: Iaf205d456b856c056b317b4e888ce892f0c555b9
Reviewed-on: https://go-review.googlesource.com/13872
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-25 14:37:08 +00:00
Russ Cox
c4092ac398 cmd/compile: fix uninitialized memory during type switch assertE2I2
Fixes arm64 builder crash.

The bug is possible on all architectures; you just have to get lucky
and hit a preemption or a stack growth on entry to assertE2I2.
The test stacks the deck.

Change-Id: I8419da909b06249b1ad15830cbb64e386b6aa5f6
Reviewed-on: https://go-review.googlesource.com/12890
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-07-30 05:21:56 +00:00
Russ Cox
c3c047a6a3 runtime: test and fix heap bitmap for 1-pointer allocation on 32-bit system
Change-Id: Ic064fe7c6bd3304dcc8c3f7b3b5393870b5387c2
Reviewed-on: https://go-review.googlesource.com/10119
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Austin Clements <austin@google.com>
2015-05-15 18:47:00 +00:00
Austin Clements
350fd548b3 runtime: don't run runq tests on the system stack
Running these tests on the system stack is problematic because they
allocate Ps, which are large enough to overflow the system stack if
they are stack-allocated. It used to be necessary to run these tests
on the system stack because they were written in C, but since this is
no longer the case, we can fix this problem by simply not running the
tests on the system stack.

This also means we no longer need the hack in one of these tests that
forces the allocated Ps to escape to the heap, so eliminate that as
well.

Change-Id: I9064f5f8fd7f7b446ff39a22a70b172cfcb2dc57
Reviewed-on: https://go-review.googlesource.com/9923
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
2015-05-12 19:58:08 +00:00
Russ Cox
6d8a147bef runtime: use 1-bit pointer bitmaps in type representation
The type information in reflect.Type and the GC programs is now
1 bit per word, down from 2 bits.

The in-memory unrolled type bitmap representation are now
1 bit per word, down from 4 bits.

The conversion from the unrolled (now 1-bit) bitmap to the
heap bitmap (still 4-bit) is not optimized. A followup CL will
work on that, after the heap bitmap has been converted to 2-bit.

The typeDead optimization, in which a special value denotes
that there are no more pointers anywhere in the object, is lost
in this CL. A followup CL will bring it back in the final form of
heapBitsSetType.

Change-Id: If61e67950c16a293b0b516a6fd9a1c755b6d5549
Reviewed-on: https://go-review.googlesource.com/9702
Reviewed-by: Austin Clements <austin@google.com>
2015-05-11 14:43:33 +00:00
Russ Cox
7d9e16abc6 runtime: add benchmark of heapBitsSetType
There was an old benchmark that measured this indirectly
via allocation, but I don't understand how to factor out the
allocation cost when interpreting the numbers.

Replace with a benchmark that only calls heapBitsSetType,
that does not allocate. This was not possible when the
benchmark was first written, because heapBitsSetType had
not been factored out of mallocgc.

Change-Id: I30f0f02362efab3465a50769398be859832e6640
Reviewed-on: https://go-review.googlesource.com/9701
Reviewed-by: Austin Clements <austin@google.com>
2015-05-11 14:40:27 +00:00
Daniel Morsing
db6f88a84b runtime: enable profiling on g0
Since we now have stack information for code running on the
systemstack, we can traceback over it. To make cpu profiles useful,
add a case in gentraceback to jump over systemstack switches.

Fixes #10609.

Change-Id: I21f47fcc802c07c5d4a1ada56374314e388a6dc7
Reviewed-on: https://go-review.googlesource.com/9506
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-05-11 08:44:30 +00:00
Shenghou Ma
102436e800 runtime: fix software FP regs corruption when emulating SQRT on ARM
When emulating ARM FSQRT instruction, the sqrt function itself
should not use any floating point arithmetics, otherwise it will
clobber the user software FP registers.

Fortunately, the sqrt function only uses floating point instructions
to test for corner cases, so it's easy to make that function does
all it job using pure integer arithmetic only. I've verified that
after this change, runtime.stepflt and runtime.sqrt doesn't contain
any call to _sfloat. (Perhaps we should add //go:nosfloat to make
the compiler enforce this?)

Fixes #10641.

Change-Id: Ida4742c49000fae4fea4649f28afde630ce4c576
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/9570
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Keith Randall <khr@golang.org>
2015-05-05 07:32:58 +00:00
Srdjan Petrovic
6ad33be2d9 runtime: implement xadduintptr and update system mstats using it
The motivation is that sysAlloc/Free() currently aren't safe to be
called without a valid G, because arm's xadd64() uses locks that require
a valid G.

The solution here was proposed by Dmitry Vyukov: use xadduintptr()
instead of xadd64(), until arm can support xadd64 on all of its
architectures (not a trivial task for arm).

Change-Id: I250252079357ea2e4360e1235958b1c22051498f
Reviewed-on: https://go-review.googlesource.com/9002
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-04-24 16:53:26 +00:00
Srdjan Petrovic
ca9128f18f runtime: merge clone0 and clone
We initially added clone0 to handle the case when G or M don't exist, but
it turns out that we could have just modified clone.  (It also helps that
the function we're invoking in clone0 no longer needs arguments.)

As a side-effect, newosproc0 is now supported on all linux archs.

Change-Id: Ie603af75d8f164310fc16446052d83743961f3ca
Reviewed-on: https://go-review.googlesource.com/9164
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-04-22 16:28:57 +00:00
Michael Hudson-Doyle
ab4df700b8 runtime: merge slice and sliceStruct
By removing type slice, renaming type sliceStruct to type slice and
whacking until it compiles.

Has a pleasing net reduction of conversions.

Fixes #10188

Change-Id: I77202b8df637185b632fd7875a1fdd8d52c7a83c
Reviewed-on: https://go-review.googlesource.com/8770
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-04-15 16:59:49 +00:00
David Crawshaw
cea272de30 runtime: rename close to closefd
Avoids shadowing the builtin channel close function.

Change-Id: I7a729b0937c8248fe27222be61318a88db995eee
Reviewed-on: https://go-review.googlesource.com/8898
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
2015-04-14 12:31:29 +00:00
David Crawshaw
402f71a839 runtime: do not share underlying envs/argv array
Removes a potential data race between os.Setenv and runtime.GOROOT,
along with a bug where os.Setenv would only sometimes change the
value of runtime.GOROOT.

Change-Id: I7d2a905115c667ea6e73f349f3784a1d3e8f810d
Reviewed-on: https://go-review.googlesource.com/6611
Reviewed-by: Keith Randall <khr@golang.org>
2015-03-09 17:25:23 +00:00
Keith Randall
f584c05fcc runtime: Update open/close/read/write to return -1 on error.
Error detection code copied from syscall, where presumably
we actually do it right.

Note that we throw the errno away.  The runtime doesn't use it.

Fixes #10052

Change-Id: I8de77dda6bf287276b137646c26b84fa61554ec8
Reviewed-on: https://go-review.googlesource.com/6571
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-03 17:46:36 +00:00
Austin Clements
428afae027 runtime: use func value for parfor body
Yet another leftover from C: parfor took a func value for the
callback, casted it to an unsafe.Pointer for storage, and then casted
it back to a func value to call it.  This is unnecessary, so just
store the body as a func value.  Beyond general cleanup, this also
eliminates the last use of unsafe in parfor.

Change-Id: Ia904af7c6c443ba75e2699835aee8e9a39b26dd8
Reviewed-on: https://go-review.googlesource.com/3396
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-01-29 17:38:32 +00:00
Austin Clements
ebbdf2a14c runtime: eliminate parfor ctx field
Prior to the conversion of the runtime to Go, this void* was
necessary to get closure information in to C callbacks.  There
are no more C callbacks and parfor is perfectly capable of
invoking a Go closure now, so eliminate ctx and all of its
unsafe-ness.  (Plus, the runtime currently doesn't use ctx for
anything.)

Change-Id: I39fc53b7dd3d7f660710abc76b0d831bfc6296d8
Reviewed-on: https://go-review.googlesource.com/3395
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-01-29 17:38:16 +00:00
Austin Clements
8e2bb7bb4a runtime: use threads slice in parfor instead of unsafe pointer math
parfor originally used a tail array for its thread array.  This got
replaced with a slice allocation in the conversion to Go, but many of
its gnarlier effects remained.  Instead of keeping track of the
pointer to the first element of the slice and using unsafe pointer
math to get at the ith element, just keep the slice around and use
regular slice indexing.  There is no longer any need for padding to
64-bit align the tail array (there hasn't been since the Go
conversion), so remove this unnecessary padding from the parfor
struct.  Finally, since the slice tracks its own length, replace the
nthrmax field with len(thr).

Change-Id: I0020a1815849bca53e3613a8fa46ae4fbae67576
Reviewed-on: https://go-review.googlesource.com/3394
Reviewed-by: Russ Cox <rsc@golang.org>
2015-01-29 17:37:57 +00:00
Keith Randall
7b2524217e runtime: fix 32-bit build
In 32-bit worlds, 8-byte objects are only aligned to 4-byte boundaries.

Change-Id: I91469a9a67b1ee31dd508a4e105c39c815ecde58
Reviewed-on: https://go-review.googlesource.com/2581
Reviewed-by: Keith Randall <khr@golang.org>
2015-01-08 21:39:57 +00:00