1 Commits

Author	SHA1	Message	Date
Wei Fu	3cd8f9734d	core/mount: use ptrace instead of go:linkname ... The Go runtime has started to [lock down future uses of linkname][1] since go1.23. In the go source code, containerd project has been marked in the comment, [hall of shame][2]. Well, the go:linkname is used to fork no-op subprocess efficiently. However, since that comment, I would like to use ptrace and remove go:linkname in the whole repository. With go1.22 `go:linkname`: ```bash $ go test -bench=. -benchmem ./ -exec sudo goos: linux goarch: amd64 pkg: github.com/containerd/containerd/v2/core/mount cpu: AMD Ryzen 7 5800H with Radeon Graphics BenchmarkBatchRunGetUsernsFD_Concurrent1-16 2440 533320 ns/op 1145 B/op 43 allocs/op BenchmarkBatchRunGetUsernsFD_Concurrent10-16 342 3661616 ns/op 11562 B/op 421 allocs/op PASS ok github.com/containerd/containerd/v2/core/mount 2.983s ``` With go1.22 `ptrace`: ```bash $ go test -bench=. -benchmem ./ -exec sudo goos: linux goarch: amd64 pkg: github.com/containerd/containerd/v2/core/mount cpu: AMD Ryzen 7 5800H with Radeon Graphics BenchmarkBatchRunGetUsernsFD_Concurrent1-16 1785 739557 ns/op 3948 B/op 68 allocs/op BenchmarkBatchRunGetUsernsFD_Concurrent10-16 328 4024300 ns/op 39601 B/op 671 allocs/op PASS ok github.com/containerd/containerd/v2/core/mount 3.104s ``` With go1.23 `ptrace`: ```bash $ go test -bench=. -benchmem ./ -exec sudo goos: linux goarch: amd64 pkg: github.com/containerd/containerd/v2/core/mount cpu: AMD Ryzen 7 5800H with Radeon Graphics BenchmarkBatchRunGetUsernsFD_Concurrent1-16 1815 723252 ns/op 4220 B/op 69 allocs/op BenchmarkBatchRunGetUsernsFD_Concurrent10-16 319 3957157 ns/op 42351 B/op 682 allocs/op PASS ok github.com/containerd/containerd/v2/core/mount 3.051s ``` Diff: The `ptrace` is slower than `go:linkname` mode. However, it's accepctable. ``` goos: linux goarch: amd64 pkg: github.com/containerd/containerd/v2/core/mount cpu: AMD Ryzen 7 5800H with Radeon Graphics │ go122-golinkname │ go122-ptrace │ go123-ptrace │ │ sec/op │ sec/op vs base │ sec/op vs base │ BatchRunGetUsernsFD_Concurrent1-16 533.3µ ± ∞ ¹ 739.6µ ± ∞ ¹ ~ (p=1.000 n=1) ² 723.3µ ± ∞ ¹ ~ (p=1.000 n=1) ² BatchRunGetUsernsFD_Concurrent10-16 3.662m ± ∞ ¹ 4.024m ± ∞ ¹ ~ (p=1.000 n=1) ² 3.957m ± ∞ ¹ ~ (p=1.000 n=1) ² geomean 1.397m 1.725m +23.45% 1.692m +21.06% ¹ need >= 6 samples for confidence interval at level 0.95 ² need >= 4 samples to detect a difference at alpha level 0.05 │ go122-golinkname │ go122-ptrace │ go123-ptrace │ │ B/op │ B/op vs base │ B/op vs base │ BatchRunGetUsernsFD_Concurrent1-16 1.118Ki ± ∞ ¹ 3.855Ki ± ∞ ¹ ~ (p=1.000 n=1) ² 4.121Ki ± ∞ ¹ ~ (p=1.000 n=1) ² BatchRunGetUsernsFD_Concurrent10-16 11.29Ki ± ∞ ¹ 38.67Ki ± ∞ ¹ ~ (p=1.000 n=1) ² 41.36Ki ± ∞ ¹ ~ (p=1.000 n=1) ² geomean 3.553Ki 12.21Ki +243.65% 13.06Ki +267.43% ¹ need >= 6 samples for confidence interval at level 0.95 ² need >= 4 samples to detect a difference at alpha level 0.05 │ go122-golinkname │ go122-ptrace │ go123-ptrace │ │ allocs/op │ allocs/op vs base │ allocs/op vs base │ BatchRunGetUsernsFD_Concurrent1-16 43.00 ± ∞ ¹ 68.00 ± ∞ ¹ ~ (p=1.000 n=1) ² 69.00 ± ∞ ¹ ~ (p=1.000 n=1) ² BatchRunGetUsernsFD_Concurrent10-16 421.0 ± ∞ ¹ 671.0 ± ∞ ¹ ~ (p=1.000 n=1) ² 682.0 ± ∞ ¹ ~ (p=1.000 n=1) ² geomean 134.5 213.6 +58.76% 216.9 +61.23% ¹ need >= 6 samples for confidence interval at level 0.95 ² need >= 4 samples to detect a difference at alpha level 0.05 ``` [1]: <https://github.com/golang/go/issues/67401> [2]: <https://github.com/golang/go/blob/release-branch.go1.23/src/runtime/proc.go#L4820> Signed-off-by: Wei Fu <fuweid89@gmail.com>	2024-08-26 21:19:50 +08:00