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| author | Keith Randall <keithr@alum.mit.edu> | 2019-04-11 09:50:59 -0700 |
|---|---|---|
| committer | Keith Randall <khr@golang.org> | 2019-06-04 17:35:20 +0000 |
| commit | fff4f599fe1c21e411a99de5c9b3777d06ce0ce6 (patch) | |
| tree | 8e048033606759d2e1ad5bb11085a5188ba3cdd0 /src/runtime/syscall_windows.go | |
| parent | 8343a0934df8f437938c55a6f0ff120c7c24a8bb (diff) | |
| download | go-fff4f599fe1c21e411a99de5c9b3777d06ce0ce6.tar.gz go-fff4f599fe1c21e411a99de5c9b3777d06ce0ce6.zip | |
cmd/compile,runtime: allocate defer records on the stack
When a defer is executed at most once in a function body,
we can allocate the defer record for it on the stack instead
of on the heap.
This should make defers like this (which are very common) faster.
This optimization applies to 363 out of the 370 static defer sites
in the cmd/go binary.
name old time/op new time/op delta
Defer-4 52.2ns ± 5% 36.2ns ± 3% -30.70% (p=0.000 n=10+10)
Fixes #6980
Update #14939
Change-Id: I697109dd7aeef9e97a9eeba2ef65ff53d3ee1004
Reviewed-on: https://go-review.googlesource.com/c/go/+/171758
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/syscall_windows.go')
| -rw-r--r-- | src/runtime/syscall_windows.go | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go index 36ad7511af..722a73d108 100644 --- a/src/runtime/syscall_windows.go +++ b/src/runtime/syscall_windows.go @@ -112,7 +112,6 @@ const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800 //go:nosplit func syscall_loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (handle, err uintptr) { lockOSThread() - defer unlockOSThread() c := &getg().m.syscall if useLoadLibraryEx { @@ -135,6 +134,7 @@ func syscall_loadsystemlibrary(filename *uint16, absoluteFilepath *uint16) (hand if handle == 0 { err = c.err } + unlockOSThread() // not defer'd after the lockOSThread above to save stack frame size. return } |