chore: optimize maps.Values and maps.Keys #17
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This PR optimizes the performance of maps.Values and maps.Keys (around 125 usages in sidero code)
by using the internal runtime functions runtime.keys and runtime.values. There is strong desire in Go Team to disable
`go:linkname` usage in user code [^1], but this is a special case where we use `Push` `linkname` pattern which is said
to be supported in the future. It is tested with both Go 1.22 and latest Go with CL 585556 [^2] applied.
To further future-proof this code, we have added a build tag `go1.22 && !go1.24` to ensure this code is only compiled
with Go 1.22 and 1.23 and falls back to the old implementation for Go 1.24 and above. This is because we don't know yet
if `runtime.keys` and `runtime.values` are going to be present in Go 1.24. We will update this code when Go 1.24 freeze
happens.
Benchstat results below (overall 26% CPU usage reduction):
```bash
~ benchstat old.txt new.txt
goos: darwin
goarch: arm64
pkg: github.com/siderolabs/gen/maps
│ old.txt │ new.txt │
│ sec/op │ sec/op vs base │
Keys/small-10 111.05n ± 0% 80.74n ± 3% -27.29% (p=0.000 n=10)
Keys/mid-10 837.8n ± 1% 607.8n ± 2% -27.46% (p=0.000 n=10)
Keys/large-10 7.717µ ± 4% 5.711µ ± 0% -26.00% (p=0.000 n=10)
Values/small-10 110.40n ± 0% 83.69n ± 0% -24.19% (p=0.000 n=10)
Values/mid-10 835.9n ± 1% 583.5n ± 1% -30.19% (p=0.000 n=10)
Values/large-10 7.720µ ± 2% 5.696µ ± 1% -26.22% (p=0.000 n=10)
geomean 894.3n 653.6n -26.92%
│ old.txt │ new.txt │
│ B/op │ B/op vs base │
Keys/small-10 80.00 ± 0% 80.00 ± 0% ~ (p=1.000 n=10) ¹
Keys/mid-10 896.0 ± 0% 896.0 ± 0% ~ (p=1.000 n=10) ¹
Keys/large-10 8.000Ki ± 0% 8.000Ki ± 0% ~ (p=1.000 n=10) ¹
Values/small-10 80.00 ± 0% 80.00 ± 0% ~ (p=1.000 n=10) ¹
Values/mid-10 896.0 ± 0% 896.0 ± 0% ~ (p=1.000 n=10) ¹
Values/large-10 8.000Ki ± 0% 8.000Ki ± 0% ~ (p=1.000 n=10) ¹
geomean 837.4 837.4 +0.00%
¹ all samples are equal
│ old.txt │ new.txt │
│ allocs/op │ allocs/op vs base │
Keys/small-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
Keys/mid-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
Keys/large-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
Values/small-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
Values/mid-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
Values/large-10 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
geomean 1.000 1.000 +0.00%
¹ all samples are equal
```
[^1]: golang/go#67401
[^2]: https://go-review.googlesource.com/c/go/+/585556
Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>
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smira
approved these changes
May 20, 2024
frezbo
approved these changes
May 20, 2024
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This PR optimizes the performance of maps.Values and maps.Keys (around 125 usages in sidero code) by using the internal runtime functions runtime.keys and runtime.values. There is strong desire in Go Team to disable
go:linknameusage in user code 1, but this is a special case where we usePushlinknamepattern which is said to be supported in the future. It is tested with both Go 1.22 and latest Go with CL 585556 2 applied.To futher future-proof this code, we have added a build tag
go1.22 && !go1.24to ensure this code is only compiled with Go 1.22 and 1.23 and falls back to the old implementation for Go 1.24 and above. This is because we don't know yet ifruntime.keysandruntime.valuesare going to be present in Go 1.24. We will update this code when Go 1.24 freeze happens.Benchstat results (overall 26% CPU usage reduction):
Footnotes
https://github.com/golang/go/issues/67401 ↩
https://go-review.googlesource.com/c/go/+/585556 ↩