65 lines
2.3 KiB
Diff
65 lines
2.3 KiB
Diff
# HG changeset patch
|
|
# User Cristian Staretu <unclejacksons@gmail.com>
|
|
# Date 1404344479 -36000
|
|
# Thu Jul 03 09:41:19 2014 +1000
|
|
# Node ID 17404efd6b02d4b3acd17070e3f89de97a145877
|
|
# Parent 837348e418f33fc7a242f56dbe2feff829532526
|
|
archive/tar: reuse temporary buffer in readHeader
|
|
|
|
A temporary 512 bytes buffer is allocated for every call to
|
|
readHeader. This buffer isn't returned to the caller and it could
|
|
be reused to lower the number of memory allocations.
|
|
|
|
This CL improves it by using a pool and zeroing out the buffer before
|
|
putting it back into the pool.
|
|
|
|
benchmark old ns/op new ns/op delta
|
|
BenchmarkListFiles100k 545249903 538832687 -1.18%
|
|
|
|
benchmark old allocs new allocs delta
|
|
BenchmarkListFiles100k 2105167 2005692 -4.73%
|
|
|
|
benchmark old bytes new bytes delta
|
|
BenchmarkListFiles100k 105903472 54831527 -48.22%
|
|
|
|
This improvement is very important if your code has to deal with a lot
|
|
of tarballs which contain a lot of files.
|
|
|
|
LGTM=dsymonds
|
|
R=golang-codereviews, dave, dsymonds, bradfitz
|
|
CC=golang-codereviews
|
|
https://codereview.appspot.com/108240044
|
|
|
|
Committer: David Symonds <dsymonds@golang.org>
|
|
|
|
diff -r 837348e418f3 -r 17404efd6b02 src/pkg/archive/tar/reader.go
|
|
--- a/src/pkg/archive/tar/reader.go Thu Jul 03 09:40:53 2014 +1000
|
|
+++ b/src/pkg/archive/tar/reader.go Thu Jul 03 09:41:19 2014 +1000
|
|
@@ -29,10 +29,11 @@
|
|
// The Next method advances to the next file in the archive (including the first),
|
|
// and then it can be treated as an io.Reader to access the file's data.
|
|
type Reader struct {
|
|
- r io.Reader
|
|
- err error
|
|
- pad int64 // amount of padding (ignored) after current file entry
|
|
- curr numBytesReader // reader for current file entry
|
|
+ r io.Reader
|
|
+ err error
|
|
+ pad int64 // amount of padding (ignored) after current file entry
|
|
+ curr numBytesReader // reader for current file entry
|
|
+ hdrBuff [blockSize]byte // buffer to use in readHeader
|
|
}
|
|
|
|
// A numBytesReader is an io.Reader with a numBytes method, returning the number
|
|
@@ -426,7 +427,9 @@
|
|
}
|
|
|
|
func (tr *Reader) readHeader() *Header {
|
|
- header := make([]byte, blockSize)
|
|
+ header := tr.hdrBuff[:]
|
|
+ copy(header, zeroBlock)
|
|
+
|
|
if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
|
|
return nil
|
|
}
|