| Age | Commit message (Collapse) | Author |
|---|
|
Move ChaCha8 code into internal/chacha8rand and use it to implement
runtime.rand, which is used for the unseeded global source for
both math/rand and math/rand/v2. This also affects the calculation of
the start point for iteration over very very large maps (when the
32-bit fastrand is not big enough).
The benefit is that misuse of the global random number generators
in math/rand and math/rand/v2 in contexts where non-predictable
randomness is important for security reasons is no longer a
security problem, removing a common mistake among programmers
who are unaware of the different kinds of randomness.
The cost is an extra 304 bytes per thread stored in the m struct
plus 2-3ns more per random uint64 due to the more sophisticated
algorithm. Using PCG looks like it would cost about the same,
although I haven't benchmarked that.
Before this, the math/rand and math/rand/v2 global generator
was wyrand (https://github.com/wangyi-fudan/wyhash).
For math/rand, using wyrand instead of the Mitchell/Reeds/Thompson
ALFG was justifiable, since the latter was not any better.
But for math/rand/v2, the global generator really should be
at least as good as one of the well-studied, specific algorithms
provided directly by the package, and it's not.
(Wyrand is still reasonable for scheduling and cache decisions.)
Good randomness does have a cost: about twice wyrand.
Also rationalize the various runtime rand references.
goos: linux
goarch: amd64
pkg: math/rand/v2
cpu: AMD Ryzen 9 7950X 16-Core Processor
│ bbb48afeb7.amd64 │ 5cf807d1ea.amd64 │
│ sec/op │ sec/op vs base │
ChaCha8-32 1.862n ± 2% 1.861n ± 2% ~ (p=0.825 n=20)
PCG_DXSM-32 1.471n ± 1% 1.460n ± 2% ~ (p=0.153 n=20)
SourceUint64-32 1.636n ± 2% 1.582n ± 1% -3.30% (p=0.000 n=20)
GlobalInt64-32 2.087n ± 1% 3.663n ± 1% +75.54% (p=0.000 n=20)
GlobalInt64Parallel-32 0.1042n ± 1% 0.2026n ± 1% +94.48% (p=0.000 n=20)
GlobalUint64-32 2.263n ± 2% 3.724n ± 1% +64.57% (p=0.000 n=20)
GlobalUint64Parallel-32 0.1019n ± 1% 0.1973n ± 1% +93.67% (p=0.000 n=20)
Int64-32 1.771n ± 1% 1.774n ± 1% ~ (p=0.449 n=20)
Uint64-32 1.863n ± 2% 1.866n ± 1% ~ (p=0.364 n=20)
GlobalIntN1000-32 3.134n ± 3% 4.730n ± 2% +50.95% (p=0.000 n=20)
IntN1000-32 2.489n ± 1% 2.489n ± 1% ~ (p=0.683 n=20)
Int64N1000-32 2.521n ± 1% 2.516n ± 1% ~ (p=0.394 n=20)
Int64N1e8-32 2.479n ± 1% 2.478n ± 2% ~ (p=0.743 n=20)
Int64N1e9-32 2.530n ± 2% 2.514n ± 2% ~ (p=0.193 n=20)
Int64N2e9-32 2.501n ± 1% 2.494n ± 1% ~ (p=0.616 n=20)
Int64N1e18-32 3.227n ± 1% 3.205n ± 1% ~ (p=0.101 n=20)
Int64N2e18-32 3.647n ± 1% 3.599n ± 1% ~ (p=0.019 n=20)
Int64N4e18-32 5.135n ± 1% 5.069n ± 2% ~ (p=0.034 n=20)
Int32N1000-32 2.657n ± 1% 2.637n ± 1% ~ (p=0.180 n=20)
Int32N1e8-32 2.636n ± 1% 2.636n ± 1% ~ (p=0.763 n=20)
Int32N1e9-32 2.660n ± 2% 2.638n ± 1% ~ (p=0.358 n=20)
Int32N2e9-32 2.662n ± 2% 2.618n ± 2% ~ (p=0.064 n=20)
Float32-32 2.272n ± 2% 2.239n ± 2% ~ (p=0.194 n=20)
Float64-32 2.272n ± 1% 2.286n ± 2% ~ (p=0.763 n=20)
ExpFloat64-32 3.762n ± 1% 3.744n ± 1% ~ (p=0.171 n=20)
NormFloat64-32 3.706n ± 1% 3.655n ± 2% ~ (p=0.066 n=20)
Perm3-32 32.93n ± 3% 34.62n ± 1% +5.13% (p=0.000 n=20)
Perm30-32 202.9n ± 1% 204.0n ± 1% ~ (p=0.482 n=20)
Perm30ViaShuffle-32 115.0n ± 1% 114.9n ± 1% ~ (p=0.358 n=20)
ShuffleOverhead-32 112.8n ± 1% 112.7n ± 1% ~ (p=0.692 n=20)
Concurrent-32 2.107n ± 0% 3.725n ± 1% +76.75% (p=0.000 n=20)
goos: darwin
goarch: arm64
pkg: math/rand/v2
│ bbb48afeb7.arm64 │ 5cf807d1ea.arm64 │
│ sec/op │ sec/op vs base │
ChaCha8-8 2.480n ± 0% 2.429n ± 0% -2.04% (p=0.000 n=20)
PCG_DXSM-8 2.531n ± 0% 2.530n ± 0% ~ (p=0.877 n=20)
SourceUint64-8 2.534n ± 0% 2.533n ± 0% ~ (p=0.732 n=20)
GlobalInt64-8 2.172n ± 1% 4.794n ± 0% +120.67% (p=0.000 n=20)
GlobalInt64Parallel-8 0.4320n ± 0% 0.9605n ± 0% +122.32% (p=0.000 n=20)
GlobalUint64-8 2.182n ± 0% 4.770n ± 0% +118.58% (p=0.000 n=20)
GlobalUint64Parallel-8 0.4307n ± 0% 0.9583n ± 0% +122.51% (p=0.000 n=20)
Int64-8 4.107n ± 0% 4.104n ± 0% ~ (p=0.416 n=20)
Uint64-8 4.080n ± 0% 4.080n ± 0% ~ (p=0.052 n=20)
GlobalIntN1000-8 2.814n ± 2% 5.643n ± 0% +100.50% (p=0.000 n=20)
IntN1000-8 4.141n ± 0% 4.139n ± 0% ~ (p=0.140 n=20)
Int64N1000-8 4.140n ± 0% 4.140n ± 0% ~ (p=0.313 n=20)
Int64N1e8-8 4.140n ± 0% 4.139n ± 0% ~ (p=0.103 n=20)
Int64N1e9-8 4.139n ± 0% 4.140n ± 0% ~ (p=0.761 n=20)
Int64N2e9-8 4.140n ± 0% 4.140n ± 0% ~ (p=0.636 n=20)
Int64N1e18-8 5.266n ± 0% 5.326n ± 1% +1.14% (p=0.001 n=20)
Int64N2e18-8 6.052n ± 0% 6.167n ± 0% +1.90% (p=0.000 n=20)
Int64N4e18-8 8.826n ± 0% 9.051n ± 0% +2.55% (p=0.000 n=20)
Int32N1000-8 4.127n ± 0% 4.132n ± 0% +0.12% (p=0.000 n=20)
Int32N1e8-8 4.126n ± 0% 4.131n ± 0% +0.12% (p=0.000 n=20)
Int32N1e9-8 4.127n ± 0% 4.132n ± 0% +0.12% (p=0.000 n=20)
Int32N2e9-8 4.132n ± 0% 4.131n ± 0% ~ (p=0.017 n=20)
Float32-8 4.109n ± 0% 4.105n ± 0% ~ (p=0.379 n=20)
Float64-8 4.107n ± 0% 4.106n ± 0% ~ (p=0.867 n=20)
ExpFloat64-8 5.339n ± 0% 5.383n ± 0% +0.82% (p=0.000 n=20)
NormFloat64-8 5.735n ± 0% 5.737n ± 1% ~ (p=0.856 n=20)
Perm3-8 26.65n ± 0% 26.80n ± 1% +0.58% (p=0.000 n=20)
Perm30-8 194.8n ± 1% 197.0n ± 0% +1.18% (p=0.000 n=20)
Perm30ViaShuffle-8 156.6n ± 0% 157.6n ± 1% +0.61% (p=0.000 n=20)
ShuffleOverhead-8 124.9n ± 0% 125.5n ± 0% +0.52% (p=0.000 n=20)
Concurrent-8 2.434n ± 3% 5.066n ± 0% +108.09% (p=0.000 n=20)
goos: linux
goarch: 386
pkg: math/rand/v2
cpu: AMD Ryzen 9 7950X 16-Core Processor
│ bbb48afeb7.386 │ 5cf807d1ea.386 │
│ sec/op │ sec/op vs base │
ChaCha8-32 11.295n ± 1% 4.748n ± 2% -57.96% (p=0.000 n=20)
PCG_DXSM-32 7.693n ± 1% 7.738n ± 2% ~ (p=0.542 n=20)
SourceUint64-32 7.658n ± 2% 7.622n ± 2% ~ (p=0.344 n=20)
GlobalInt64-32 3.473n ± 2% 7.526n ± 2% +116.73% (p=0.000 n=20)
GlobalInt64Parallel-32 0.3198n ± 0% 0.5444n ± 0% +70.22% (p=0.000 n=20)
GlobalUint64-32 3.612n ± 0% 7.575n ± 1% +109.69% (p=0.000 n=20)
GlobalUint64Parallel-32 0.3168n ± 0% 0.5403n ± 0% +70.51% (p=0.000 n=20)
Int64-32 7.673n ± 2% 7.789n ± 1% ~ (p=0.122 n=20)
Uint64-32 7.773n ± 1% 7.827n ± 2% ~ (p=0.920 n=20)
GlobalIntN1000-32 6.268n ± 1% 9.581n ± 1% +52.87% (p=0.000 n=20)
IntN1000-32 10.33n ± 2% 10.45n ± 1% ~ (p=0.233 n=20)
Int64N1000-32 10.98n ± 2% 11.01n ± 1% ~ (p=0.401 n=20)
Int64N1e8-32 11.19n ± 2% 10.97n ± 1% ~ (p=0.033 n=20)
Int64N1e9-32 11.06n ± 1% 11.08n ± 1% ~ (p=0.498 n=20)
Int64N2e9-32 11.10n ± 1% 11.01n ± 2% ~ (p=0.995 n=20)
Int64N1e18-32 15.23n ± 2% 15.04n ± 1% ~ (p=0.973 n=20)
Int64N2e18-32 15.89n ± 1% 15.85n ± 1% ~ (p=0.409 n=20)
Int64N4e18-32 18.96n ± 2% 19.34n ± 2% ~ (p=0.048 n=20)
Int32N1000-32 10.46n ± 2% 10.44n ± 2% ~ (p=0.480 n=20)
Int32N1e8-32 10.46n ± 2% 10.49n ± 2% ~ (p=0.951 n=20)
Int32N1e9-32 10.28n ± 2% 10.26n ± 1% ~ (p=0.431 n=20)
Int32N2e9-32 10.50n ± 2% 10.44n ± 2% ~ (p=0.249 n=20)
Float32-32 13.80n ± 2% 13.80n ± 2% ~ (p=0.751 n=20)
Float64-32 23.55n ± 2% 23.87n ± 0% ~ (p=0.408 n=20)
ExpFloat64-32 15.36n ± 1% 15.29n ± 2% ~ (p=0.316 n=20)
NormFloat64-32 13.57n ± 1% 13.79n ± 1% +1.66% (p=0.005 n=20)
Perm3-32 45.70n ± 2% 46.99n ± 2% +2.81% (p=0.001 n=20)
Perm30-32 399.0n ± 1% 403.8n ± 1% +1.19% (p=0.006 n=20)
Perm30ViaShuffle-32 349.0n ± 1% 350.4n ± 1% ~ (p=0.909 n=20)
ShuffleOverhead-32 322.3n ± 1% 323.8n ± 1% ~ (p=0.410 n=20)
Concurrent-32 3.331n ± 1% 7.312n ± 1% +119.50% (p=0.000 n=20)
For #61716.
Change-Id: Ibdddeed85c34d9ae397289dc899e04d4845f9ed2
Reviewed-on: https://go-review.googlesource.com/c/go/+/516860
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
|
|
Move code to detect and mask arm64 CPU features from
runtime to internal/cpu.
Change-Id: Ib784e2ff056e8def125d68827b852f07a3eff0db
Reviewed-on: https://go-review.googlesource.com/c/go/+/261878
Trust: Martin Möhrmann <moehrmann@google.com>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
|
|
Some, but not all, architectures mix in OS-provided random seeds when
initializing the fastrand state. The others have TODOs saying we need
to do the same. Lift that logic up in the architecture-independent
part, and use memhash to mix the seed instead of a simple addition.
Previously, dumping the fastrand state at initialization would yield
something like the following on linux-amd64, where the values in the
first column do not change between runs (as thread IDs are sequential
and always start at 0), and the values in the second column, while
changing every run, are pretty correlated:
first run:
0x0 0x44d82f1c
0x5f356495 0x44f339de
0xbe6ac92a 0x44f91cd8
0x1da02dbf 0x44fd91bc
0x7cd59254 0x44fee8a4
0xdc0af6e9 0x4547a1e0
0x3b405b7e 0x474c76fc
0x9a75c013 0x475309dc
0xf9ab24a8 0x4bffd075
second run:
0x0 0xa63fc3eb
0x5f356495 0xa6648dc2
0xbe6ac92a 0xa66c1c59
0x1da02dbf 0xa671bce8
0x7cd59254 0xa70e8287
0xdc0af6e9 0xa7129d2e
0x3b405b7e 0xa7379e2d
0x9a75c013 0xa7e4c64c
0xf9ab24a8 0xa7ecce07
With this change, we get initial states that appear to be much more
unpredictable, both within the same run as well as between runs:
0x11bddad7 0x97241c63
0x553dacc6 0x2bcd8523
0x62c01085 0x16413d92
0x6f40e9e6 0x7a138de6
0xa4898053 0x70d816f0
0x5ca5b433 0x188a395b
0x62778ca9 0xd462c3b5
0xd6e160e4 0xac9b4bd
0xb9571d65 0x597a981d
Change-Id: Ib22c530157d74200df0083f830e0408fd4aaea58
Reviewed-on: https://go-review.googlesource.com/c/go/+/203439
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
|
|
OpenBSD does not provide auxv, however we still need to initialise cpu.HWCap.
For now initialise it to the bare minimum, until some form of CPU capability
detection is implemented or becomes available - see issue #31746.
Updates #31656
Change-Id: I68c3c069319fe60dc873f46def2a67c9f3d937d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/174129
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
|
|
Updates #31656
Change-Id: I0b7486f7381fd8bd16a76278c0e9ec9763671fcc
Reviewed-on: https://go-review.googlesource.com/c/go/+/174119
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
|
