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| author | Josh Bleecher Snyder <josharian@gmail.com> | 2019-03-02 11:14:33 -0800 |
|---|---|---|
| committer | Josh Bleecher Snyder <josharian@gmail.com> | 2019-03-02 20:11:47 +0000 |
| commit | beadf433c37498dafc6748cc510eeab2636b5be3 (patch) | |
| tree | 253d503e500e66fae542f65e1dd91797f71fd110 /src/os/exec | |
| parent | 37b84e2782e5c19c3053316853a6fba923b0f06b (diff) | |
| download | go-beadf433c37498dafc6748cc510eeab2636b5be3.tar.xz | |
os/exec: provide map size hint in dedupEnvCase
The common case is that most env vars are distinct;
optimize for that.
name old time/op new time/op delta
ExecEcho-8 2.16ms ± 3% 2.14ms ± 1% ~ (p=0.315 n=10+10)
name old alloc/op new alloc/op delta
ExecEcho-8 7.87kB ± 0% 6.35kB ± 0% -19.31% (p=0.000 n=9+10)
name old allocs/op new allocs/op delta
ExecEcho-8 72.0 ± 0% 69.0 ± 0% -4.17% (p=0.000 n=10+10)
Change-Id: I42bb696c6862f2ea12c5cbd2f24c64336a7a759a
Reviewed-on: https://go-review.googlesource.com/c/164960
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Diffstat (limited to 'src/os/exec')
| -rw-r--r-- | src/os/exec/exec.go | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go index 1aa3ab93dc..7b2b2ebd92 100644 --- a/src/os/exec/exec.go +++ b/src/os/exec/exec.go @@ -713,7 +713,7 @@ func dedupEnv(env []string) []string { // If caseInsensitive is true, the case of keys is ignored. func dedupEnvCase(caseInsensitive bool, env []string) []string { out := make([]string, 0, len(env)) - saw := map[string]int{} // key => index into out + saw := make(map[string]int, len(env)) // key => index into out for _, kv := range env { eq := strings.Index(kv, "=") if eq < 0 { |