encoding/hex: don't overallocate memory in DecodeString
Now as []byte(string) doesn't always cause heap allocation (CL 520599, #2205)
we can make DecodeString simpler and more performant, by not allocating
x2 the required memory.
goos: linux
goarch: amd64
pkg: encoding/hex
cpu: AMD Ryzen 5 4600G with Radeon Graphics
│ beforehex │ afterhex │
│ sec/op │ sec/op vs base │
DecodeString/256-12 197.9n ± 1% 172.2n ± 1% -13.01% (p=0.000 n=10)
DecodeString/1024-12 684.9n ± 1% 598.5n ± 1% -12.61% (p=0.000 n=10)
DecodeString/4096-12 2.764µ ± 0% 2.343µ ± 1% -15.23% (p=0.000 n=10)
DecodeString/16384-12 10.774µ ± 1% 9.348µ ± 1% -13.23% (p=0.000 n=10)
geomean 1.417µ 1.226µ -13.53%
│ beforehex │ afterhex │
│ B/s │ B/s vs base │
DecodeString/256-12 1.205Gi ± 1% 1.385Gi ± 1% +14.94% (p=0.000 n=10)
DecodeString/1024-12 1.393Gi ± 1% 1.593Gi ± 1% +14.42% (p=0.000 n=10)
DecodeString/4096-12 1.380Gi ± 0% 1.628Gi ± 1% +17.97% (p=0.000 n=10)
DecodeString/16384-12 1.416Gi ± 1% 1.632Gi ± 1% +15.25% (p=0.000 n=10)
geomean 1.346Gi 1.556Gi +15.64%
│ beforehex │ afterhex │
│ B/op │ B/op vs base │
DecodeString/256-12 256.0 ± 0% 128.0 ± 0% -50.00% (p=0.000 n=10)
DecodeString/1024-12 1024.0 ± 0% 512.0 ± 0% -50.00% (p=0.000 n=10)
DecodeString/4096-12 4.000Ki ± 0% 2.000Ki ± 0% -50.00% (p=0.000 n=10)
DecodeString/16384-12 16.000Ki ± 0% 8.000Ki ± 0% -50.00% (p=0.000 n=10)
geomean 2.000Ki 1.000Ki -50.00%
│ beforehex │ afterhex │
│ allocs/op │ allocs/op vs base │
DecodeString/256-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
DecodeString/1024-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
DecodeString/4096-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
DecodeString/16384-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹
geomean 1.000 1.000 +0.00%
Change-Id: I5676e48f222d90786ea18e808cb4ecde9de82597
GitHub-Last-Rev:
aeedf3f6c4a2505ae9cc0ae58a94c6b2f30806fd
GitHub-Pull-Request: golang/go#67259
Reviewed-on: https://go-review.googlesource.com/c/go/+/584118
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>