Commit Graph

8 Commits

Author SHA1 Message Date
Alan Donovan 3ca52f4c31 slices: add in-place Reverse function
Fixes #58565

Change-Id: I583f8380c12386178fb18e553322bbb019d9fae0
Reviewed-on: https://go-review.googlesource.com/c/go/+/468855
Run-TryBot: Alan Donovan <adonovan@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Shay Nehmad <dude500@gmail.com>
2023-05-19 00:43:02 +00:00
Keith Randall 6d1c507bfc slices: for Insert and Replace, grow slices like append does
At least when we're inserting/replacing near the end of a slice, when
we have to grow it use the same multiplicative growth factor that the
runtime uses for append.

Before this CL, we would grow the slice one page (8192 bytes) at a time
for large slices. This would cause O(n^2) work when appending near the
end should only take O(n) work.

This doesn't fix the problem if you insert/replace near the start of the
array, but maybe that doesn't need fixing because it is O(n^2) anyway.

Fixes #60134

Change-Id: If05376bc512ab839769180e5ce4cb929f47363b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/495296
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
2023-05-16 23:34:59 +00:00
Keith Randall 882cc4d596 slices: handle aliasing cases in Insert/Replace
Handle cases where the inserted slice is actually part of the slice
that is being inserted into.

Requires a bit more work, but no more allocations. (Compare to #494536.)

Not entirely sure this is worth the complication.

Fixes #60138

Change-Id: Ia72c872b04309b99025e6ca5a4a326ebed2abb69
Reviewed-on: https://go-review.googlesource.com/c/go/+/494817
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
2023-05-16 23:34:50 +00:00
Egon Elbre 9d53d7aa02 slices: optimize Index and Compact for large types
Using `for i, v := range` loops causes extra copies.
Try to get rid of as much copies as possible.

  goos: windows
  goarch: amd64
  pkg: slices
  cpu: AMD Ryzen Threadripper 2950X 16-Core Processor
                       │   old.txt~    │               new.txt~               │
                       │    sec/op     │    sec/op     vs base                │
  EqualFunc_Large-32       1.077m ± 1%   1.072m ±  1%        ~ (p=0.631 n=10)
  Index_Large-32         346.329µ ± 1%   6.510µ ± 24%  -98.12% (p=0.000 n=10)
  IndexFunc_Large-32       502.9µ ± 0%   381.2µ ±  1%  -24.21% (p=0.000 n=10)
  Compact_Large-32         409.5µ ± 1%   145.2µ ±  9%  -64.54% (p=0.000 n=10)
  CompactFunc_Large-32     693.5µ ± 1%   663.1µ ±  3%   -4.39% (p=0.000 n=10)
  geomean                  556.3µ        191.3µ        -65.61%

Change-Id: I36a2f2172cf30d97a5aa6f8d7cf6981d67daec62
Reviewed-on: https://go-review.googlesource.com/c/go/+/486235
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
2023-04-19 19:09:29 +00:00
Ian Lance Taylor 3de5b4da26 slices: amortize allocations in Insert
Fixes #54948

Change-Id: I467afb940b539b100dcce687b05914a9da7b9ed2
Reviewed-on: https://go-review.googlesource.com/c/go/+/484159
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Valentin Deleplace <deleplace@google.com>
2023-04-13 17:55:12 +00:00
Ian Lance Taylor 693a34e788 slices: add DeleteFunc
Fixes #54768

Change-Id: I588ae33c13e0bbd9d324c11771667b22a864047d
Reviewed-on: https://go-review.googlesource.com/c/go/+/483175
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Eli Bendersky <eliben@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
2023-04-07 22:25:51 +00:00
Ian Lance Taylor 54e109ea19 slices: skip TestGrow allocation test if noopt
Change-Id: Ie444367c6bb16ed78482d1786b546e6daa63444a
Reviewed-on: https://go-review.googlesource.com/c/go/+/468196
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
2023-02-14 17:50:49 +00:00
Ian Lance Taylor 1e9925f461 slices: new package
This copies parts of x/exp/slices into the standard library.
We omit all functions that depend on constraints.Ordered,
and the Func variants of all such functions. In particular this
omits the various Sort and Search functions.

Fixes #57433

Change-Id: I3c28f4c2e6bd1e3c9ad70e120a0dd68065388f77
Reviewed-on: https://go-review.googlesource.com/c/go/+/467417
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Eli Bendersky <eliben@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
2023-02-13 21:00:42 +00:00