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https://github.com/quasilyte/go-complex-nums-emulation
Emulating builtin complex numbers with structs of floats and measuring the results
https://github.com/quasilyte/go-complex-nums-emulation
benchmark go go2
Last synced: 2 months ago
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Emulating builtin complex numbers with structs of floats and measuring the results
- Host: GitHub
- URL: https://github.com/quasilyte/go-complex-nums-emulation
- Owner: quasilyte
- License: mit
- Created: 2017-09-06T23:31:53.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2017-09-09T07:37:05.000Z (over 7 years ago)
- Last Synced: 2024-10-11T11:48:24.146Z (3 months ago)
- Topics: benchmark, go, go2
- Language: Go
- Size: 37.1 KB
- Stars: 10
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Go complex numbers: builtin vs library implementation
See [proposal: remove complex numbers](https://github.com/golang/go/issues/19921).
This repository:
1. Implements most `complex64` operations with user-defined type `Complex64`.
2. Measures performance of `complex64` VS `Complex64`.
3. Provides `amd64` machine code output for both builtin and `Complex64` operations.
Results and conclusions may be extrapolated to `complex128`.
**This is performance comparison of the potential implementation, not a library**.
## TL;DR
```
# old is builtin complex64
# new is user-defined Complex64
name old time/op new time/op delta
Logical-4 2.89µs ± 1% 2.77µs ± 8% ~ (p=0.108 n=9+10)
Add64-4 1.50µs ± 1% 1.51µs ± 1% ~ (p=0.174 n=9+10)
Sub64-4 1.50µs ± 1% 1.52µs ± 1% +0.80% (p=0.000 n=9+10)
Mul64-4 6.50µs ± 2% 6.74µs ± 7% ~ (p=0.101 n=10+10)
Div64-4 52.6µs ± 0% 47.9µs ± 7% -8.99% (p=0.000 n=9+10)
```
> Note: it is strange that Sub/Add/Mul time differs as their
> machine code is exactly the same on amd64 (see "Machine code comparison").
```
go test -bench=.
BenchmarkLogicalBuiltin-4 500000 2876 ns/op
BenchmarkLogical-4 500000 2711 ns/op
BenchmarkAdd64Builtin-4 1000000 1539 ns/op
BenchmarkAdd64-4 1000000 1516 ns/op
BenchmarkSub64Builtin-4 1000000 1511 ns/op
BenchmarkSub64-4 1000000 1568 ns/op
BenchmarkMul64Builtin-4 200000 6476 ns/op
BenchmarkMul64-4 200000 6456 ns/op
BenchmarkDiv64Builtin-4 30000 52589 ns/op
BenchmarkDiv64-4 30000 44854 ns/op
```
## Benchmark results.
Results stored in "benchmark-results/".
Structure is "benchmark-results/$arch/$machine_id/$version".
Each machine folder can contain some hardware/system info:
- `lscpu.txt`, the result of `lscpu` invocation result
- `uname.txt`, optional `uname -a` invocation result
For each version that was tested on that machine, there is "v$number"
folder, which consist of:
- `builtin.out` & `lib.out` - results of the benchmark runs
- `benchstat.txt` result of `benchstat builtin.out lib.out`
## Run benchmark
[Benchstat](https://godoc.org/golang.org/x/perf/cmd/benchstat) is required to
aggregate benchmark statistics.
See [run-benchmarks](script/run-benchmarks) bash script for detailed instruction.
## Machine code comparison
Most code looks the same, but some code compiled
to different instruction sequences.
Look inside [disasm.go](disasm.go) to inspect objdump output.
## Edge cases / limitations
### Constant semantics
[Spec:complex_numbers](https://golang.org/ref/spec#Complex_numbers): `complex`, `imag` and `real`
can be a constant value.
> If the operands of these functions are all constants, the return value is a constant.
User-defined struct literal is never a constant.
## Versions
* 1 : up to 1c7348b2f4683432625a7e1c9c9b434fd48b6ad7
initial implementation
* 2 : from 41112b4215a2d02aca055a751f8e4047168397c5
[alternative Eq/Neq/IsZero implementation](https://github.com/Quasilyte/go-complex-nums-emulation/issues/2)