Renames block to blockGeneric so that it can be called when the
assembly feature check fails. This means making block a var on
platforms without an assembly implementation (similar to the sha1
package).
Also adds a test to check that the fallback path works correctly
when the feature check fails.
name old speed new speed delta
Hash8Bytes 6.42MB/s ± 1% 27.14MB/s ± 0% +323.01% (p=0.000 n=10+10)
Hash1K 53.9MB/s ± 0% 511.1MB/s ± 0% +847.57% (p=0.000 n=10+9)
Hash8K 57.1MB/s ± 1% 609.7MB/s ± 0% +967.04% (p=0.000 n=10+10)
Change-Id: If962b2a5c9160b3a0b76ccee53b2fd809468ed3d
Reviewed-on: https://go-review.googlesource.com/22460
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bill O'Farrell <billotosyr@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently we clear gcscanvalid in both casgstatus and
casfrom_Gscanstatus if the new status is _Grunning. This is very
important to do in casgstatus. However, this is potentially wrong in
casfrom_Gscanstatus because in this case the caller doesn't own gp and
hence the write is racy. Unlike the other _Gscan statuses, during
_Gscanrunning, the G is still running. This does not indicate that
it's transitioning into a running state. The scan simply hasn't
happened yet, so it's neither valid nor invalid.
Conveniently, this also means clearing gcscanvalid is unnecessary in
this case because the G was already in _Grunning, so we can simply
remove this code. What will happen instead is that the G will be
preempted to scan itself, that scan will set gcscanvalid to true, and
then the G will return to _Grunning via casgstatus, clearing
gcscanvalid.
This fix will become necessary shortly when we start keeping track of
the set of G's with dirty stacks, since it will no longer be
idempotent to simply set gcscanvalid to false.
Change-Id: I688c82e6fbf00d5dbbbff49efa66acb99ee86785
Reviewed-on: https://go-review.googlesource.com/20669
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This adds a best-effort pass to remove stack barriers immediately
after the end of mark termination. This isn't necessary for the Go
runtime, but should help external tools that perform stack walks but
aren't aware of Go's stack barriers such as GDB, perf, and VTune.
(Though clearly they'll still have trouble unwinding stacks during
mark.)
Change-Id: I66600fae1f03ee36b5459d2b00dcc376269af18e
Reviewed-on: https://go-review.googlesource.com/20668
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently we remove stack barriers during STW mark termination, which
has a non-trivial per-goroutine cost and means that we have to touch
even clean stacks during mark termination. However, there's no problem
with leaving them in during the sweep phase. They just have to be out
by the time we install new stack barriers immediately prior to
scanning the stack such as during the mark phase of the next GC cycle
or during mark termination in a STW GC.
Hence, move the gcRemoveStackBarriers from STW mark termination to
just before we install new stack barriers during concurrent mark. This
removes the cost from STW. Furthermore, this combined with concurrent
stack shrinking means that the mark termination scan of a clean stack
is a complete no-op, which will make it possible to skip clean stacks
entirely during mark termination.
This has the downside that it will mess up anything outside of Go that
tries to walk Go stacks all the time instead of just some of the time.
This includes tools like GDB, perf, and VTune. We'll improve the
situation shortly.
Change-Id: Ia40baad8f8c16aeefac05425e00b0cf478137097
Reviewed-on: https://go-review.googlesource.com/20667
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently we enqueue span root mark jobs during both concurrent mark
and mark termination, but we make the job a no-op during mark
termination.
This is silly. Instead of queueing them up just to not do them, don't
queue them up in the first place.
Change-Id: Ie1d36de884abfb17dd0db6f0449a2b7c997affab
Reviewed-on: https://go-review.googlesource.com/20666
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently we free cached stacks of dead Gs during STW stack root
marking. We do this during STW because there's no way to take
ownership of a particular dead G, so attempting to free a dead G's
stack during concurrent stack root marking could race with reusing
that G.
However, we can do this concurrently if we take a completely different
approach. One way to prevent reuse of a dead G is to remove it from
the free G list. Hence, this adds a new fixed root marking task that
simply removes all Gs from the list of dead Gs with cached stacks,
frees their stacks, and then adds them to the list of dead Gs without
cached stacks.
This is also a necessary step toward rescanning only dirty stacks,
since it eliminates another task from STW stack marking.
Change-Id: Iefbad03078b284a2e7bf30fba397da4ca87fe095
Reviewed-on: https://go-review.googlesource.com/20665
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently all free Gs are added to one list. Split this into two
lists: one for free Gs with cached stacks and one for Gs without
cached stacks.
This lets us preferentially allocate Gs that already have a stack, but
more importantly, it sets us up to free cached G stacks concurrently.
Change-Id: Idbe486f708997e1c9d166662995283f02d1eeb3c
Reviewed-on: https://go-review.googlesource.com/20664
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Let's define the line number of a multiline rule as the line
number on which the -> appears. This helps make the rule
cover analysis look a bit nicer.
Change-Id: I4ac4c09f2240285976590ecfd416bc4c05e78946
Reviewed-on: https://go-review.googlesource.com/22473
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Instead of eagerly creating strings like "literal 2.01" for every
lexed number in case we need to mention it in an error message, defer
this work to (*parser).syntax_error.
name old allocs/op new allocs/op delta
Template 482k ± 0% 482k ± 0% -0.12% (p=0.000 n=9+10)
GoTypes 1.35M ± 0% 1.35M ± 0% -0.04% (p=0.015 n=10+10)
Compiler 5.45M ± 0% 5.44M ± 0% -0.12% (p=0.000 n=9+8)
Change-Id: I333b3c80e583864914412fb38f8c0b7f1d8c8821
Reviewed-on: https://go-review.googlesource.com/22480
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This simplifies comparison of object files across different builds
by ensuring that the strings in the zcgo.go always appear in the
same order.
Change-Id: I3639ea4fd10e0d645b838d1bbb03cd33deca340e
Reviewed-on: https://go-review.googlesource.com/22478
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This version of the file name honors the -trimprefix flag,
which strips off variable parts like $WORK or $PWD.
The TestCgoConsistentResults test now passes.
Change-Id: If93980b054f9b13582dd314f9d082c26eaac4f41
Reviewed-on: https://go-review.googlesource.com/22444
Reviewed-by: Robert Griesemer <gri@golang.org>
Also adds TestGdbBacktrace to the runtime package.
Dwarf modifications written by Bryan Chan (@bryanpkc) who is also
at IBM and covered by the same CLA.
Fixes#14628
Change-Id: I106a1f704c3745a31f29cdadb0032e3905829850
Reviewed-on: https://go-review.googlesource.com/20193
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The comment says 'DΟ NΟT SUBMIT', and that text being in a file can cause
automated errors or warnings when trying to check the Go sources into other
source control systems.
(We reject that string in CL commit messages, which I've avoided here
by changing the O's to Ο's above.)
Change-Id: I6cdd57a8612ded5208f05a8bd6b137f44424a030
Reviewed-on: https://go-review.googlesource.com/22434
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Make sure ops have the right number of args, set
aux and auxint only if allowed, etc.
Normalize error reporting format.
Change-Id: Ie545fcc5990c8c7d62d40d9a0a55885f941eb645
Reviewed-on: https://go-review.googlesource.com/22320
Reviewed-by: David Chase <drchase@google.com>
Renames block to blockGeneric so that it can be called when the
assembly feature check fails. This means making block a var on
platforms without an assembly implementation (similar to the sha1
package).
Also adds a test to check that the fallback path works correctly
when the feature check fails.
name old speed new speed delta
Hash8Bytes 7.13MB/s ± 2% 19.89MB/s ± 1% +178.82% (p=0.000 n=9+10)
Hash1K 121MB/s ± 1% 661MB/s ± 1% +444.54% (p=0.000 n=10+9)
Hash8K 137MB/s ± 0% 918MB/s ± 1% +569.29% (p=0.000 n=10+10)
Change-Id: Id65dd6e943f14eeffe39a904dc88065fc6a60179
Reviewed-on: https://go-review.googlesource.com/22402
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The linker was incorrectly decoding type name lengths, causing
typelinks to be sorted out of order and in cases where the name was
the exact right length, linker panics.
Added a test to the reflect package that causes TestTypelinksSorted
to fail before this CL. It's not the exact failure seen in #15448
but it has the same cause: decodetype_name calculating the wrong
length.
The equivalent decoders in reflect/type.go and runtime/type.go
have the parenthesis in the right place.
Fixes#15448
Change-Id: I33257633d812b7d2091393cb9d6cc8a73e0138c8
Reviewed-on: https://go-review.googlesource.com/22403
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Here, "fix" means "replace". The new dominator computation
is the "simple" algorithm from Lengauer and Tarjan's TOPLAS
paper, with minimal changes.
Also included is a test that tweaks the fixed error.
Change-Id: I0abdf53d5d64df1e67e4e62f55e88957045cd63b
Reviewed-on: https://go-review.googlesource.com/22401
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This is not necessary for reproduceability but it removes
differences due to imported package order between compiles
using textual vs binary export format. The packages list
tends to be very short, so it's ok doing it always for now.
Guarded with a documented (const) flag so it's trivial to
disable and remove eventually.
Also, use the same flag now to enforce parameter numbering.
Change-Id: Ie05d2490df770239696ecbecc07532ed62ccd5c0
Reviewed-on: https://go-review.googlesource.com/22445
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The code sequence for large-offset floating-point stores
includes adding the base pointer to r11. Make sure we
can interpret that instruction correctly.
Fixes build.
Fixes#15440
Change-Id: I7fe5a4a57e08682967052bf77c54e0ec47fcb53e
Reviewed-on: https://go-review.googlesource.com/22440
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
The numbering is only required for parameters of functions/methods
with exported inlineable bodies. For now, always export parameter names
with internal numbering to minimize the diffs between assembly code
dumps of code compiled with the textual vs the binary format.
To be disabled again once the new export format is default.
Change-Id: I6d14c564e734cc5596c7e995d8851e06d5a35013
Reviewed-on: https://go-review.googlesource.com/22441
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Zero the entire buffer so we don't need to
lower its capacity upon return. This lets callers
do some appending without allocation.
Zeroing is cheap, the byte buffer requires only
4 extra instructions.
Fixes#14235
Change-Id: I970d7badcef047dafac75ac17130030181f18fe2
Reviewed-on: https://go-review.googlesource.com/22424
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Note that the spec already makes that point with a comment in the very first
example for struct field tags. This change is simply stating this explicitly
in the actual spec prose.
- gccgo and go/types already follow this rule
- the current reflect package API doesn't distinguish between absent tags
and empty tags (i.e., there is no discoverable difference)
Fixes#15412.
Change-Id: I92f9c283064137b4c8651630cee0343720717a02
Reviewed-on: https://go-review.googlesource.com/22391
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The underlying issues have been fixed.
All the individual fixes have their own tests,
but it's still useful to have a plain source test.
Fixes#15084
Change-Id: I06c485a7d0716201bd57d1f3be53668dddd7ec14
Reviewed-on: https://go-review.googlesource.com/22426
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
As a nice side-effect, this allows us to
unify several code paths.
The terminology (low, high, max, simple slice expr,
full slice expr) is taken from the spec and
the examples in the spec.
This is a trial run. The plan, probably for Go 1.8,
is to change slice expressions to use Node.List
instead of OKEY, and to do some similar
tree structure changes for other ops.
Passes toolstash -cmp. No performance change.
all.bash passes with GO_GCFLAGS=-newexport.
Updates #15350
Change-Id: Ic1efdc36e79cdb95ae1636e9817a3ac8f83ab1ac
Reviewed-on: https://go-review.googlesource.com/22425
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
* Make budget an int32 to avoid needless conversions.
* Introduce some temporary variables to reduce repetition.
* If ... args are present, they will be the last argument
to the function. No need to scan all arguments.
Passes toolstash -cmp.
Change-Id: I55203609f5d2f25a4e238cd48c63214651120cfc
Reviewed-on: https://go-review.googlesource.com/22421
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This is a follow-up to CLs 19769 and 19770.
Change-Id: Ia9b71055613b80df4ce62b34fcc4f479f04f72fd
Reviewed-on: https://go-review.googlesource.com/22399
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Note that this is only safe because
the compiler generates multiple distinct
gc.Types. If we switch to having canonical
gc.Types, then this will need to be updated
to handle the case in which the user uses both
map[T]S and also map[[8]T]S. In that case,
the runtime needs algs for [8]T, but this could
mark the sole [8]T type as Noalg. This is a general
problem with having a single bool to represent
whether alg generation is needed for a type.
Cuts 5k off cmd/go and 22k off golang.org/x/tools/cmd/godoc,
approx 0.04% and 0.12% respectively.
For #6853 and #9930
Change-Id: I30a15ec72ecb62e2aa053260a7f0f75015fc0ade
Reviewed-on: https://go-review.googlesource.com/19769
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Note that this is only safe because
the compiler generates multiple distinct
gc.Types. If we switch to having canonical
gc.Types, then this will need to be updated
to handle the case in which the user uses both
map[[n]T]S and also calls a function f(...T) with n arguments.
In that case, the runtime needs algs for [n]T, but this could
mark the sole [n]T type as Noalg. This is a general
problem with having a single bool to represent
whether alg generation is needed for a type.
Cuts 17k off cmd/go and 13k off golang.org/x/tools/cmd/godoc,
approx 0.14% and 0.07% respectively.
For #6853 and #9930
Change-Id: Iccb6b9fd88ade5497d7090528a903816d340bf0a
Reviewed-on: https://go-review.googlesource.com/19770
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
func f(x, y, z *int) {
a := []*int{x,y,z}
...
}
We used to use:
var tmp [3]*int
a := tmp[:]
a[0] = x
a[1] = y
a[2] = z
Now we do:
var tmp [3]*int
tmp[0] = x
tmp[1] = y
tmp[2] = z
a := tmp[:]
Doesn't sound like a big deal, but the compiler has trouble
eliminating write barriers when using the former method because it
doesn't know that the slice points to the stack. In the latter
method, the compiler knows the array is on the stack and as a result
doesn't emit any write barriers.
This turns out to be extremely common when building ... args, like
for calls fmt.Printf.
Makes go binaries ~1% smaller.
Doesn't have a measurable effect on the go1 fmt benchmarks,
unfortunately.
Fixes#14263
Update #6853
Change-Id: I9074a2788ec9e561a75f3b71c119b69f304d6ba2
Reviewed-on: https://go-review.googlesource.com/22395
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
On some processors cputicks (used to generate trace timestamps)
produce non-monotonic timestamps. It is important that the parser
distinguishes logically inconsistent traces (e.g. missing, excessive
or misordered events) from broken timestamps. The former is a bug
in tracer, the latter is a machine issue.
Test that (1) parser does not return a logical error in case of
broken timestamps and (2) broken timestamps are eventually detected
and reported.
Change-Id: Ib4b1eb43ce128b268e754400ed8b5e8def04bd78
Reviewed-on: https://go-review.googlesource.com/21608
Reviewed-by: Austin Clements <austin@google.com>
Reloc.SymbolTableIndex is an index into symbol table. But
Reloc.SymbolTableIndex cannot be used as index into File.Symbols,
because File.Symbols slice has Aux lines removed as it is built.
We cannot change the way File.Symbols works, so I propose we
introduce new File.COFFSymbols that does not have that limitation.
Also unlike File.Symbols, File.COFFSymbols will consist of
COFFSymbol. COFFSymbol matches PE COFF specification exactly,
and it is simpler to use.
Updates #15345
Change-Id: Icbc265853a472529cd6d64a76427b27e5459e373
Reviewed-on: https://go-review.googlesource.com/22336
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Now that we're using 32-bit ops for 8/16-bit logical operations
(to avoid partial register stalls), there's really no need to
keep track of the 8/16-bit ops at all. Convert everything we
can to 32-bit ops.
This CL is the obvious stuff. I might think a bit more about
whether we can get rid of weirder stuff like HMULWU.
The only downside to this CL is that we lose some information
about constants. If we had source like:
var a byte = ...
a += 128
a += 128
We will convert that to a += 256, when we could get rid of the
add altogether. This seems like a fairly unusual scenario and
I'm happy with forgoing that optimization.
Change-Id: Ia7c1e5203d0d110807da69ed646535194a3efba1
Reviewed-on: https://go-review.googlesource.com/22382
Reviewed-by: Todd Neal <todd@tneal.org>
Combine stores into larger widths when it is safe to do so.
Add clobber() function so stray dead uses do not impede the
above rewrites.
Fix bug in loads where all intermediate values depending on
a small load (not just the load itself) must have no other uses.
We really need the small load to be dead after the rewrite..
Fixes#14267
Change-Id: Ib25666cb19777f65082c76238fba51a76beb5d74
Reviewed-on: https://go-review.googlesource.com/22326
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Todd Neal <todd@tneal.org>
Currently tracer uses global sequencer and it introduces
significant slowdown on parallel machines (up to 10x).
Replace the global sequencer with per-goroutine sequencer.
If we assign per-goroutine sequence numbers to only 3 types
of events (start, unblock and syscall exit), it is enough to
restore consistent partial ordering of all events. Even these
events don't need sequence numbers all the time (if goroutine
starts on the same P where it was unblocked, then start does
not need sequence number).
The burden of restoring the order is put on trace parser.
Details of the algorithm are described in the comments.
On http benchmark with GOMAXPROCS=48:
no tracing: 5026 ns/op
tracing: 27803 ns/op (+453%)
with this change: 6369 ns/op (+26%, mostly for traceback)
Also trace size is reduced by ~22%. Average event size before: 4.63
bytes/event, after: 3.62 bytes/event.
Besides running trace tests, I've also tested with manually broken
cputicks (random skew for each event, per-P skew and episodic random skew).
In all cases broken timestamps were detected and no test failures.
Change-Id: I078bde421ccc386a66f6c2051ab207bcd5613efa
Reviewed-on: https://go-review.googlesource.com/21512
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
