这种填充方式能解决 false sharing 吗，
type PaddedStruct struct {
_ CacheLinePad
n int
}
type CacheLinePad struct {
_ [CacheLinePadSize]byte
}
const CacheLinePadSize = 64
CacheLinePad 后面的字段，是怎么避免和其他结构体不共享一个 Cache 块了，把 CacheLinePad 放在第一个字段，只能避免和它前面的数据不在一个 cache 块吧，是不是应该这样
type PaddedStruct struct {
_ CacheLinePad
n int
_ CacheLinePad
}
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1
slowman Sep 2, 2022
On ARM, 386, and 32-bit MIPS, ........ The first word in an allocated struct, array, or slice; in a global variable; or in a local variable can be relied upon to be 64-bit aligned.
https://pkg.go.dev/sync/atomic |
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2
slowman Sep 2, 2022
啊，请忽略上条
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3
qwe678 Sep 3, 2022
struct PaddedStruct {
int a; char cache_line_pad[64]; int b; }; |
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6
lysS Sep 4, 2022
我测出来了，性能差了 3 倍以上，https://go.dev/play/p/WF-CoUIe4bd
goos: windows goarch: amd64 pkg: btest cpu: 11th Gen Intel(R) Core(TM) i5-11320H @ 3.20GHz BenchmarkD1 BenchmarkD1-8 582 1844166 ns/op 66 B/op 3 allocs/op BenchmarkD2 BenchmarkD2-8 2710 387049 ns/op 59 B/op 3 allocs/op BenchmarkC1 BenchmarkC1-8 583 1974648 ns/op 53 B/op 2 allocs/op BenchmarkC2 BenchmarkC2-8 2938 396749 ns/op 42 B/op 2 allocs/op PASS ok btest 4.985s |
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7
lysS Sep 4, 2022
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1
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