go/test/codegen/mathbits.go, branch fix-runtime-test-GOMAXPROCS

cmd/compile,internal/cpu,runtime: intrinsify math/bits.OnesCount on riscv64

2025-05-01T12:57:41Z

For riscv64/rva22u64 and above, we can intrinsify math/bits.OnesCount using the CPOP/CPOPW machine instructions. Since the native Go implementation of OnesCount is relatively expensive, it is also worth emitting a check for Zbb support when compiled for rva20u64. On a Banana Pi F3, with GORISCV64=rva22u64: │ oc.1 │ oc.2 │ │ sec/op │ sec/op vs base │ OnesCount-8 16.930n ± 0% 4.389n ± 0% -74.08% (p=0.000 n=10) OnesCount8-8 5.642n ± 0% 5.016n ± 0% -11.10% (p=0.000 n=10) OnesCount16-8 9.404n ± 0% 5.015n ± 0% -46.67% (p=0.000 n=10) OnesCount32-8 13.165n ± 0% 4.388n ± 0% -66.67% (p=0.000 n=10) OnesCount64-8 16.300n ± 0% 4.388n ± 0% -73.08% (p=0.000 n=10) geomean 11.40n 4.629n -59.40% On a Banana Pi F3, compiled with GORISCV64=rva20u64 and with Zbb detection enabled: │ oc.3 │ oc.4 │ │ sec/op │ sec/op vs base │ OnesCount-8 16.930n ± 0% 5.643n ± 0% -66.67% (p=0.000 n=10) OnesCount8-8 5.642n ± 0% 5.642n ± 0% ~ (p=0.447 n=10) OnesCount16-8 10.030n ± 0% 6.896n ± 0% -31.25% (p=0.000 n=10) OnesCount32-8 13.170n ± 0% 5.642n ± 0% -57.16% (p=0.000 n=10) OnesCount64-8 16.300n ± 0% 5.642n ± 0% -65.39% (p=0.000 n=10) geomean 11.55n 5.873n -49.16% On a Banana Pi F3, compiled with GORISCV64=rva20u64 but with Zbb detection disabled: │ oc.3 │ oc.5 │ │ sec/op │ sec/op vs base │ OnesCount-8 16.93n ± 0% 29.47n ± 0% +74.07% (p=0.000 n=10) OnesCount8-8 5.642n ± 0% 5.643n ± 0% ~ (p=0.191 n=10) OnesCount16-8 10.03n ± 0% 15.05n ± 0% +50.05% (p=0.000 n=10) OnesCount32-8 13.17n ± 0% 18.18n ± 0% +38.04% (p=0.000 n=10) OnesCount64-8 16.30n ± 0% 21.94n ± 0% +34.60% (p=0.000 n=10) geomean 11.55n 15.84n +37.16% For hardware without Zbb, this adds ~5ns overhead, while for hardware with Zbb we achieve a performance gain up of up to 11ns. It is worth noting that OnesCount8 is cheap enough that it is preferable to stick with the generic version in this case. Change-Id: Id657e40e0dd1b1ab8cc0fe0f8a68df4c9f2d7da5 Reviewed-on: https://go-review.googlesource.com/c/go/+/660856 Reviewed-by: Carlos Amedee Reviewed-by: Meng Zhuo Reviewed-by: Mark Ryan Reviewed-by: Dmitri Shuralyov LUCI-TryBot-Result: Go LUCI

cmd/compile: intrinsify math/bits.Bswap on riscv64

2025-05-01T12:57:13Z

For riscv64/rva22u64 and above, we can intrinsify math/bits.Bswap using the REV8 machine instruction. On a StarFive VisionFive 2 with GORISCV64=rva22u64: │ rb.1 │ rb.2 │ │ sec/op │ sec/op vs base │ ReverseBytes-4 18.790n ± 0% 4.026n ± 0% -78.57% (p=0.000 n=10) ReverseBytes16-4 6.710n ± 0% 5.368n ± 0% -20.00% (p=0.000 n=10) ReverseBytes32-4 13.420n ± 0% 5.368n ± 0% -60.00% (p=0.000 n=10) ReverseBytes64-4 17.450n ± 0% 4.026n ± 0% -76.93% (p=0.000 n=10) geomean 13.11n 4.649n -64.54% Change-Id: I26eee34270b1721f7304bb1cddb0fda129b20ece Reviewed-on: https://go-review.googlesource.com/c/go/+/660855 Reviewed-by: Mark Ryan LUCI-TryBot-Result: Go LUCI Reviewed-by: Meng Zhuo Reviewed-by: Carlos Amedee Reviewed-by: Junyang Shao

cmd/compile: constant fold 128-bit multiplies

2025-04-22T17:24:18Z

The full 64x64->128 multiply comes up when using bits.Mul64. The 64x64->64+overflow multiply comes up in unsafe.Slice when using a constant length. Change-Id: I298515162ca07d804b2d699d03bc957ca30a4ebc Reviewed-on: https://go-review.googlesource.com/c/go/+/667175 Reviewed-by: Junyang Shao Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI

cmd/compile: intrinsify math/bits.Len on riscv64

2025-03-22T01:21:44Z

For riscv64/rva22u64 and above, we can intrinsify math/bits.Len using the CLZ/CLZW machine instructions. On a StarFive VisionFive 2 with GORISCV64=rva22u64: │ clz.b.1 │ clz.b.2 │ │ sec/op │ sec/op vs base │ LeadingZeros-4 28.89n ± 0% 12.08n ± 0% -58.19% (p=0.000 n=10) LeadingZeros8-4 18.79n ± 0% 14.76n ± 0% -21.45% (p=0.000 n=10) LeadingZeros16-4 25.27n ± 0% 14.76n ± 0% -41.59% (p=0.000 n=10) LeadingZeros32-4 25.12n ± 0% 12.08n ± 0% -51.92% (p=0.000 n=10) LeadingZeros64-4 25.89n ± 0% 12.08n ± 0% -53.35% (p=0.000 n=10) geomean 24.55n 13.09n -46.70% Change-Id: I0dda684713dbdf5336af393f5ccbdae861c4f694 Reviewed-on: https://go-review.googlesource.com/c/go/+/652321 Reviewed-by: David Chase Reviewed-by: Meng Zhuo LUCI-TryBot-Result: Go LUCI Reviewed-by: Mark Ryan Reviewed-by: Cherry Mui

cmd/compile: intrinsify math/bits.TrailingZeros on riscv64

2025-03-16T02:07:53Z

For riscv64/rva22u64 and above, we can intrinsify math/bits.TrailingZeros using the CTZ/CTZW machine instructions. On a StarFive VisionFive 2 with GORISCV64=rva22u64: │ ctz.b.1 │ ctz.b.2 │ │ sec/op │ sec/op vs base │ TrailingZeros-4 25.500n ± 0% 8.052n ± 0% -68.42% (p=0.000 n=10) TrailingZeros8-4 14.76n ± 0% 10.74n ± 0% -27.24% (p=0.000 n=10) TrailingZeros16-4 26.84n ± 0% 10.74n ± 0% -59.99% (p=0.000 n=10) TrailingZeros32-4 25.500n ± 0% 8.052n ± 0% -68.42% (p=0.000 n=10) TrailingZeros64-4 25.500n ± 0% 8.052n ± 0% -68.42% (p=0.000 n=10) geomean 23.09n 9.035n -60.88% Change-Id: I71edf2b988acb7a68e797afda4ee66d7a57d587e Reviewed-on: https://go-review.googlesource.com/c/go/+/652320 Reviewed-by: Cherry Mui Reviewed-by: Mark Ryan Reviewed-by: David Chase LUCI-TryBot-Result: Go LUCI Reviewed-by: Meng Zhuo

test/codegen: tighten the TrailingZeros64 test on 386

2025-03-14T22:04:38Z

Make the TrailingZeros64 code generation check more specific for 386. Just checking for BSFL will match both the generic 64 bit decomposition and the custom 386 lowering. Change-Id: I62076f1889af0ef1f29704cba01ab419cae0c6e3 Reviewed-on: https://go-review.googlesource.com/c/go/+/656996 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Reviewed-by: Keith Randall Auto-Submit: Keith Randall Reviewed-by: Keith Randall

cmd/compile: simplify intrinsification of TrailingZeros16 and TrailingZeros8

2025-02-27T11:45:44Z

Decompose Ctz16 and Ctz8 within the SSA rules for LOONG64, MIPS, PPC64 and S390X, rather than having a custom intrinsic. Note that for PPC64 this actually allows the existing Ctz16 and Ctz8 rules to be used. Change-Id: I27a5e978f852b9d75396d2a80f5d7dfcb5ef7dd4 Reviewed-on: https://go-review.googlesource.com/c/go/+/651816 Reviewed-by: Paul Murphy TryBot-Result: Gopher Robot LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Pratt Run-TryBot: Joel Sing Reviewed-by: Keith Randall Reviewed-by: Keith Randall

cmd/compile: wire up math/bits.TrailingZeros intrinsics for loong64

2024-11-13T00:57:25Z

Micro-benchmark results on Loongson 3A5000 and 3A6000: goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A6000 @ 2500.00MHz | bench.old | bench.new | | sec/op | sec/op vs base | TrailingZeros 1.7240n ± 0% 0.8120n ± 0% -52.90% (p=0.000 n=20) TrailingZeros8 1.0530n ± 0% 0.8015n ± 0% -23.88% (p=0.000 n=20) TrailingZeros16 2.072n ± 0% 1.015n ± 0% -51.01% (p=0.000 n=20) TrailingZeros32 1.7160n ± 0% 0.8122n ± 0% -52.67% (p=0.000 n=20) TrailingZeros64 2.0060n ± 0% 0.8125n ± 0% -59.50% (p=0.000 n=20) geomean 1.669n 0.8470n -49.25% goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A5000 @ 2500.00MHz | bench.old | bench.new | | sec/op | sec/op vs base | TrailingZeros 2.6275n ± 0% 0.9120n ± 0% -65.29% (p=0.000 n=20) TrailingZeros8 1.451n ± 0% 1.163n ± 0% -19.85% (p=0.000 n=20) TrailingZeros16 3.069n ± 0% 1.201n ± 0% -60.87% (p=0.000 n=20) TrailingZeros32 2.9060n ± 0% 0.9115n ± 0% -68.63% (p=0.000 n=20) TrailingZeros64 2.6305n ± 0% 0.9115n ± 0% -65.35% (p=0.000 n=20) geomean 2.456n 1.011n -58.83% This patch is a copy of CL 479498. Co-authored-by: WANG Xuerui Change-Id: I1a5b2114a844dc0d02c8e68f41ce2443ac3b5fda Reviewed-on: https://go-review.googlesource.com/c/go/+/624356 Reviewed-by: abner chenc Reviewed-by: David Chase Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI Reviewed-by: Keith Randall

cmd/compile: optimize math/bits.OnesCount{16,32,64} implementation on loong64

2024-11-12T00:48:04Z

Use Loong64's LSX instruction VPCNT to implement math/bits.OnesCount{16,32,64} and make it intrinsic. Benchmark results on loongson 3A5000 and 3A6000 machines: goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A5000-HV @ 2500.00MHz | bench.old | bench.new | | sec/op | sec/op vs base | OnesCount 4.413n ± 0% 1.401n ± 0% -68.25% (p=0.000 n=10) OnesCount8 1.364n ± 0% 1.363n ± 0% ~ (p=0.130 n=10) OnesCount16 2.112n ± 0% 1.534n ± 0% -27.37% (p=0.000 n=10) OnesCount32 4.533n ± 0% 1.529n ± 0% -66.27% (p=0.000 n=10) OnesCount64 4.565n ± 0% 1.531n ± 1% -66.46% (p=0.000 n=10) geomean 3.048n 1.470n -51.78% goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A6000 @ 2500.00MHz | bench.old | bench.new | | sec/op | sec/op vs base | OnesCount 3.553n ± 0% 1.201n ± 0% -66.20% (p=0.000 n=10) OnesCount8 0.8021n ± 0% 0.8004n ± 0% -0.21% (p=0.000 n=10) OnesCount16 1.216n ± 0% 1.000n ± 0% -17.76% (p=0.000 n=10) OnesCount32 3.006n ± 0% 1.035n ± 0% -65.57% (p=0.000 n=10) OnesCount64 3.503n ± 0% 1.035n ± 0% -70.45% (p=0.000 n=10) geomean 2.053n 1.006n -51.01% Change-Id: I07a5b8da2bb48711b896387ec7625145804affc8 Reviewed-on: https://go-review.googlesource.com/c/go/+/620978 Reviewed-by: David Chase Reviewed-by: Cherry Mui Reviewed-by: Meidan Li LUCI-TryBot-Result: Go LUCI

cmd/compile: wire up bits.Reverse intrinsics for loong64

2024-11-11T00:08:45Z

Micro-benchmark results on Loongson 3A5000 and 3A6000: goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A6000 @ 2500.00MHz | CL 624576 | this CL | | sec/op | sec/op vs base | Reverse 2.8130n ± 0% 0.8008n ± 0% -71.53% (p=0.000 n=20) Reverse8 0.7014n ± 0% 0.4040n ± 0% -42.40% (p=0.000 n=20) Reverse16 1.2975n ± 0% 0.6632n ± 1% -48.89% (p=0.000 n=20) Reverse32 2.7520n ± 0% 0.4042n ± 0% -85.31% (p=0.000 n=20) Reverse64 2.8970n ± 0% 0.4041n ± 0% -86.05% (p=0.000 n=20) geomean 1.828n 0.5116n -72.01% goos: linux goarch: loong64 pkg: math/bits cpu: Loongson-3A5000 @ 2500.00MHz | CL 624576 | this CL | | sec/op | sec/op vs base | Reverse 4.0050n ± 0% 0.8011n ± 0% -80.00% (p=0.000 n=20) Reverse8 0.8010n ± 0% 0.5210n ± 1% -34.96% (p=0.000 n=20) Reverse16 1.6160n ± 0% 0.6008n ± 0% -62.82% (p=0.000 n=20) Reverse32 3.8550n ± 0% 0.5179n ± 0% -86.57% (p=0.000 n=20) Reverse64 3.8050n ± 0% 0.5177n ± 0% -86.40% (p=0.000 n=20) geomean 2.378n 0.5828n -75.49% Updates #59120 This patch is a copy of CL 483656. Co-authored-by: WANG Xuerui Change-Id: I98681091763279279c8404bd0295785f13ea1c8e Reviewed-on: https://go-review.googlesource.com/c/go/+/624276 Reviewed-by: abner chenc LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui Reviewed-by: David Chase