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  1. 23 Apr, 2016 4 commits
    • Keith Randall's avatar
      cmd/compile: get rid of most byte and word insns for amd64 · 9e3c68f1
      Keith Randall authored 
      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/22382Reviewed-by: 's avatarTodd Neal <todd@tneal.org>
      9e3c68f1
    • Keith Randall's avatar
      cmd/compile: combine stores into larger widths · 217c2849
      Keith Randall authored 
      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: 's avatarTodd Neal <todd@tneal.org>
      217c2849
    • Dmitry Vyukov's avatar
      runtime: use per-goroutine sequence numbers in tracer · a3703618
      Dmitry Vyukov authored 
      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: 's avatarAustin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      a3703618
    • Francesc Campoy's avatar
      doc: mention security from contribution guidelines · ba966f5d
      Francesc Campoy authored 
      Fixes #15413

Change-Id: I837a391276eed565cf66d3715ec68b7b959ce143
Reviewed-on: https://go-review.googlesource.com/22390Reviewed-by: 's avatarAndrew Gerrand <adg@golang.org>
      ba966f5d
  3. 22 Apr, 2016 26 commits
  5. 21 Apr, 2016 10 commits
    • Robert Griesemer's avatar
      flag: update test case (fix build) · 70184087
      Robert Griesemer authored 
      Change-Id: I2275dc703be4fda3feedf76483148eab853b43b8
Reviewed-on: https://go-review.googlesource.com/22360
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: 's avatarRob Pike <r@golang.org>
      70184087
    • Michael Hudson-Doyle's avatar
      cmd/link: convert Link.Filesyms into a slice · 25d95ee9
      Michael Hudson-Doyle authored 
      Change-Id: I6490de325b0f4ba962c679503102d30d41dcc384
Reviewed-on: https://go-review.googlesource.com/22359
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: 's avatarBrad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      25d95ee9
    • Michael Hudson-Doyle's avatar
      cmd/link: fix Codeblk printing when -a to use Textp as a slice · 4b175fd2
      Michael Hudson-Doyle authored 
      Does anyone actually pass -a to the linker?

Change-Id: I1d31ea66aa5604b7fd42adf15bdab71e9f52d0ed
Reviewed-on: https://go-review.googlesource.com/22356
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: 's avatarDavid Crawshaw <crawshaw@golang.org>
      4b175fd2
    • Rob Pike's avatar
      doc/go1.7.txt: 0s for zero duration, go doc groups constructors with types · 0ef041cf
      Rob Pike authored 
      Change-Id: I4fc35649ff5a3510f5667b62e7e84e113e95dffe
Reviewed-on: https://go-review.googlesource.com/22358Reviewed-by: 's avatarRob Pike <r@golang.org>
      0ef041cf
    • Rob Pike's avatar
      time: print zero duration as 0s, not 0 · 9c4295b5
      Rob Pike authored 
      There should be a unit, and s is the SI unit name, so use that.
The other obvious possibility is ns (nanosecond), but the fact
that durations are measured in nanoseconds is an internal detail.

Fixes #14058.

Change-Id: Id1f8f3c77088224d9f7cd643778713d5cc3be5d9
Reviewed-on: https://go-review.googlesource.com/22357Reviewed-by: 's avatarRobert Griesemer <gri@golang.org>
      9c4295b5
    • Rob Pike's avatar
      cmd/doc: group constructors with type in package presentation · a33e9cf7
      Rob Pike authored 
      Fixes #14004.

$ go doc encoding.gob
Before:
func Register(value interface{})
func RegisterName(name string, value interface{})
func NewDecoder(r io.Reader) *Decoder
func NewEncoder(w io.Writer) *Encoder
type CommonType struct { ... }
type Decoder struct { ... }
type Encoder struct { ... }
type GobDecoder interface { ... }
type GobEncoder interface { ... }

After:
func Register(value interface{})
func RegisterName(name string, value interface{})
type CommonType struct { ... }
type Decoder struct { ... }
    func NewDecoder(r io.Reader) *Decoder
type Encoder struct { ... }
    func NewEncoder(w io.Writer) *Encoder
type GobDecoder interface { ... }
type GobEncoder interface { ... }

Change-Id: I021db25bce4a16b3dfa22ab323ca1f4e68d50111
Reviewed-on: https://go-review.googlesource.com/22354Reviewed-by: 's avatarRobert Griesemer <gri@golang.org>
      a33e9cf7
    • Keith Randall's avatar
      cmd/compile: Use pre-regalloc value ID in lateSpillUse · 8ad8d7d8
      Keith Randall authored 
      The cached copy's ID is sometimes outside the bounds of the orig array.

There's no reason to start at the cached copy and work backwards
to the original value. We already have the original value ID at
all the callsites.

Fixes noopt build

Change-Id: I313508a1917e838a87e8cc83b2ef3c2e4a8db304
Reviewed-on: https://go-review.googlesource.com/22355
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: 's avatarDavid Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      8ad8d7d8
    • Matthew Dempsky's avatar
      cmd/compile: split TSLICE into separate Type kind · 40f1d0ca
      Matthew Dempsky authored 
      Instead of using TARRAY for both arrays and slices, create a new
TSLICE kind to handle slices.

Also, get rid of the "DDDArray" distinction. While kinda ugly, it
seems likely we'll need to defer evaluating the constant bounds
expressions for golang.org/issue/13890.

Passes toolstash/buildall.

Change-Id: I8e45d4900e7df3a04cce59428ec8b38035d3cc3a
Reviewed-on: https://go-review.googlesource.com/22329Reviewed-by: 's avatarJosh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      40f1d0ca
    • Robert Griesemer's avatar
      spec: fix incorrect comment in shift example · 5213cd70
      Robert Griesemer authored 
      - adjusted example code
- fixed comments

Fixes #14785.

Change-Id: Ia757dc93b0a69b8408559885ece7f3685a37daaa
Reviewed-on: https://go-review.googlesource.com/22353Reviewed-by: 's avatarRob Pike <r@golang.org>
      5213cd70
    • Austin Clements's avatar
      runtime: eliminate floating garbage estimate · c8bd293e
      Austin Clements authored 
      Currently when we compute the trigger for the next GC, we do it based
on an estimate of the reachable heap size at the start of the GC
cycle, which is itself based on an estimate of the floating garbage.
This was introduced by 4655aadd to fix a bad feedback loop that allowed
the heap to grow to many times the true reachable size.

However, this estimate gets easily confused by rapidly allocating
applications, and, worse it's different than the heap size the trigger
controller uses to compute the trigger itself. This results in the
trigger controller often thinking that GC finished before it started.
Since this would be a pretty great outcome from it's perspective, it
sets the trigger for the next cycle as close to the next goal as
possible (which is limited to 95% of the goal).

Furthermore, the bad feedback loop this estimate originally fixed
seems not to happen any more, suggesting it was fixed more correctly
by some other change in the mean time. Finally, with the change to
allocate black, it shouldn't even be theoretically possible for this
bad feedback loop to occur.

Hence, eliminate the floating garbage estimate and simply consider the
reachable heap to be the marked heap. This harms overall throughput
slightly for allocation-heavy benchmarks, but significantly improves
mutator availability.

Fixes #12204. This brings the average trigger in this benchmark from
0.95 (the cap) to 0.7 and the active GC utilization from ~90% to ~45%.

Updates #14951. This makes the trigger controller much better behaved,
so it pulls the trigger lower if assists are consuming a lot of CPU
like it's supposed to, increasing mutator availability.

name              old time/op  new time/op  delta
XBenchGarbage-12  2.21ms ± 1%  2.28ms ± 3%  +3.29%  (p=0.000 n=17+17)

Some of this slow down we paid for in earlier commits. Relative to the
start of the series to switch to allocate-black (the parent of "count
black allocations toward scan work"), the garbage benchmark is 2.62%
slower.

name                      old time/op    new time/op    delta
BinaryTree17-12              2.53s ± 3%     2.53s ± 3%    ~     (p=0.708 n=20+19)
Fannkuch11-12                2.08s ± 0%     2.08s ± 0%  -0.22%  (p=0.002 n=19+18)
FmtFprintfEmpty-12          45.3ns ± 2%    45.2ns ± 3%    ~     (p=0.505 n=20+20)
FmtFprintfString-12          129ns ± 0%     131ns ± 2%  +1.80%  (p=0.000 n=16+19)
FmtFprintfInt-12             121ns ± 2%     121ns ± 2%    ~     (p=0.768 n=19+19)
FmtFprintfIntInt-12          186ns ± 1%     188ns ± 3%  +0.99%  (p=0.000 n=19+19)
FmtFprintfPrefixedInt-12     188ns ± 1%     188ns ± 1%    ~     (p=0.947 n=18+16)
FmtFprintfFloat-12           254ns ± 1%     255ns ± 1%  +0.30%  (p=0.002 n=19+17)
FmtManyArgs-12               763ns ± 0%     770ns ± 0%  +0.92%  (p=0.000 n=18+18)
GobDecode-12                7.00ms ± 1%    7.04ms ± 1%  +0.61%  (p=0.049 n=20+20)
GobEncode-12                5.88ms ± 1%    5.88ms ± 0%    ~     (p=0.641 n=18+19)
Gzip-12                      214ms ± 1%     215ms ± 1%  +0.43%  (p=0.002 n=18+19)
Gunzip-12                   37.6ms ± 0%    37.6ms ± 0%  +0.11%  (p=0.015 n=17+18)
HTTPClientServer-12         76.9µs ± 2%    78.1µs ± 2%  +1.44%  (p=0.000 n=20+18)
JSONEncode-12               15.2ms ± 2%    15.1ms ± 1%    ~     (p=0.271 n=19+18)
JSONDecode-12               53.1ms ± 1%    53.3ms ± 0%  +0.49%  (p=0.000 n=18+19)
Mandelbrot200-12            4.04ms ± 1%    4.03ms ± 0%  -0.33%  (p=0.005 n=18+18)
GoParse-12                  3.29ms ± 1%    3.28ms ± 1%    ~     (p=0.146 n=16+17)
RegexpMatchEasy0_32-12      69.9ns ± 3%    69.5ns ± 1%    ~     (p=0.785 n=20+19)
RegexpMatchEasy0_1K-12       237ns ± 0%     237ns ± 0%    ~     (p=1.000 n=18+18)
RegexpMatchEasy1_32-12      69.5ns ± 1%    69.2ns ± 1%  -0.44%  (p=0.020 n=16+19)
RegexpMatchEasy1_1K-12       372ns ± 1%     371ns ± 2%    ~     (p=0.086 n=20+19)
RegexpMatchMedium_32-12      108ns ± 3%     107ns ± 1%  -1.00%  (p=0.004 n=19+14)
RegexpMatchMedium_1K-12     34.2µs ± 4%    34.0µs ± 2%    ~     (p=0.380 n=19+20)
RegexpMatchHard_32-12       1.77µs ± 4%    1.76µs ± 3%    ~     (p=0.558 n=18+20)
RegexpMatchHard_1K-12       53.4µs ± 4%    52.8µs ± 2%  -1.10%  (p=0.020 n=18+20)
Revcomp-12                   359ms ± 4%     377ms ± 0%  +5.19%  (p=0.000 n=20+18)
Template-12                 63.7ms ± 2%    62.9ms ± 2%  -1.27%  (p=0.005 n=18+20)
TimeParse-12                 316ns ± 2%     313ns ± 1%    ~     (p=0.059 n=20+16)
TimeFormat-12                329ns ± 0%     331ns ± 0%  +0.39%  (p=0.000 n=16+18)
[Geo mean]                  51.6µs         51.7µs       +0.18%

Change-Id: I1dce4640c8205d41717943b021039fffea863c57
Reviewed-on: https://go-review.googlesource.com/21324Reviewed-by: 's avatarRick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
      c8bd293e