Names of sub-benchmarks are preserved, short of the additional slash.
Change-Id: I9b3f82964f9a44b0d28724413320afd091ed3106
Reviewed-on: https://go-review.googlesource.com/23425
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
MOVSB is quite a bit faster for unaligned moves.
Possibly we should use MOVSB all of the time, but Intel folks
say it might be a bit faster to use MOVSQ on some processors
(but not any I have access to at the moment).
benchmark old ns/op new ns/op delta
BenchmarkMemmove4096-8 93.9 93.2 -0.75%
BenchmarkMemmoveUnalignedDst4096-8 256 151 -41.02%
BenchmarkMemmoveUnalignedSrc4096-8 175 90.5 -48.29%
Fixes#14630
Change-Id: I568e6d6590eb3615e6a699fb474020596be665ff
Reviewed-on: https://go-review.googlesource.com/20293
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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>
It is faster to execute
MOVQ AX,(DI)
MOVQ AX,8(DI)
MOVQ AX,16(DI)
MOVQ AX,24(DI)
ADDQ $32,DI
than
STOSQ
STOSQ
STOSQ
STOSQ
However, in order to be able to jump into
the middle of a block of MOVQs, the call
site needs to pre-adjust DI.
If we're clearing a small area, the cost
of that DI pre-adjustment isn't repaid.
This CL switches the DUFFZERO implementation
to use a hybrid strategy, in which small
clears use STOSQ as before, but large clears
use mostly MOVQ/ADDQ blocks.
benchmark old ns/op new ns/op delta
BenchmarkClearFat8 0.55 0.55 +0.00%
BenchmarkClearFat12 0.82 0.83 +1.22%
BenchmarkClearFat16 0.55 0.55 +0.00%
BenchmarkClearFat24 0.82 0.82 +0.00%
BenchmarkClearFat32 2.20 1.94 -11.82%
BenchmarkClearFat40 1.92 1.66 -13.54%
BenchmarkClearFat48 2.21 1.93 -12.67%
BenchmarkClearFat56 3.03 2.20 -27.39%
BenchmarkClearFat64 3.26 2.48 -23.93%
BenchmarkClearFat72 3.57 2.76 -22.69%
BenchmarkClearFat80 3.83 3.05 -20.37%
BenchmarkClearFat88 4.14 3.30 -20.29%
BenchmarkClearFat128 5.54 4.69 -15.34%
BenchmarkClearFat256 9.95 9.09 -8.64%
BenchmarkClearFat512 18.7 17.9 -4.28%
BenchmarkClearFat1024 36.2 35.4 -2.21%
Change-Id: Ic786406d9b3cab68d5a231688f9e66fcd1bd7103
Reviewed-on: https://go-review.googlesource.com/2585
Reviewed-by: Keith Randall <khr@golang.org>
Recognize loops of the form
for i := range a {
a[i] = zero
}
in which the evaluation of a is free from side effects.
Replace these loops with calls to memclr.
This occurs in the stdlib in 18 places.
The motivating example is clearing a byte slice:
benchmark old ns/op new ns/op delta
BenchmarkGoMemclr5 3.31 3.26 -1.51%
BenchmarkGoMemclr16 13.7 3.28 -76.06%
BenchmarkGoMemclr64 50.8 4.14 -91.85%
BenchmarkGoMemclr256 157 6.02 -96.17%
Update #5373.
Change-Id: I99d3e6f5f268e8c6499b7e661df46403e5eb83e4
Reviewed-on: https://go-review.googlesource.com/2520
Reviewed-by: Keith Randall <khr@golang.org>
