internal/zstd: optimize window reset using make for buffer allocation
Optimize the zstd window's reset function to use `make` for buffer
allocation when needed. This ensures efficient memory usage by
conditionally reallocating the buffer based on its capacity, improving
performance in scenarios where the existing buffer is insufficient.
```
goos: darwin
goarch: amd64
pkg: internal/zstd
cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
│ old.out │ new.out │
│ sec/op │ sec/op vs base │
Large-12 7.299m ± 5% 7.235m ± 1% ~ (p=0.353 n=10)
│ old.out │ new.out │
│ B/s │ B/s vs base │
Large-12 35.56Mi ± 4% 35.87Mi ± 1% ~ (p=0.353 n=10)
│ old.out │ new.out │
│ B/op │ B/op vs base │
Large-12 68.86Ki ± 4% 15.87Ki ± 1% -76.95% (p=0.000 n=10)
│ old.out │ new.out │
│ allocs/op │ allocs/op vs base │
Large-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹
¹ all samples are equal
```
Change-Id: Icd9c278b42ea149107a9861d006f40129c59831b
GitHub-Last-Rev: c00344cca415342eb563c62e325f1c2f7f28327d
GitHub-Pull-Request: golang/go#64221
Reviewed-on: https://go-review.googlesource.com/c/go/+/543375
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
diff --git a/src/internal/zstd/window.go b/src/internal/zstd/window.go
index f9c5f04..11596df 100644
--- a/src/internal/zstd/window.go
+++ b/src/internal/zstd/window.go
@@ -19,7 +19,11 @@
// reset clears stored data and configures window size.
func (w *window) reset(size int) {
- w.data = w.data[:0]
+ b := w.data[:0]
+ if cap(b) < size {
+ b = make([]byte, 0, size)
+ }
+ w.data = b
w.off = 0
w.size = size
}
