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Optimize Patricia tree

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Remove all the extra allocations in the Patricia tree.

O(1) allocation for Patricia and  ~10% improvement for HTTP1 matching.

benchmark                      old ns/op     new ns/op     delta
BenchmarkCMuxConnHTTP1-4       908           782           -13.88%
BenchmarkCMuxConnHTTP2-4       835           818           -2.04%
BenchmarkCMuxConnHTTP1n2-4     1074          1033          -3.82%
BenchmarkCMuxConnHTTP2n1-4     1010          901           -10.79%

benchmark                      old allocs     new allocs     delta
BenchmarkCMuxConnHTTP1-4       5              3              -40.00%
BenchmarkCMuxConnHTTP2-4       4              4              +0.00%
BenchmarkCMuxConnHTTP1n2-4     6              4              -33.33%
BenchmarkCMuxConnHTTP2n1-4     6              4              -33.33%

benchmark                      old bytes     new bytes     delta
BenchmarkCMuxConnHTTP1-4       276           272           -1.45%
BenchmarkCMuxConnHTTP2-4       304           304           +0.00%
BenchmarkCMuxConnHTTP1n2-4     306           304           -0.65%
BenchmarkCMuxConnHTTP2n1-4     308           304           -1.30%
This commit is contained in:
Soheil Hassas Yeganeh 2016-05-03 21:52:24 -04:00
parent d45bcbe1db
commit 703b087a39
1 changed files with 31 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

74
patricia.go
View File

@ -9,11 +9,19 @@ import (
// and cannot be changed after instantiation.
type patriciaTree struct {
root *ptNode
buf []byte // preallocated buffer to read data while matching
}
func newPatriciaTree(b ...[]byte) *patriciaTree {
func newPatriciaTree(bs ...[]byte) *patriciaTree {
max := 0
for _, b := range bs {
if max < len(b) {
max = len(b)
}
}
return &patriciaTree{
root: newNode(b),
root: newNode(bs),
buf: make([]byte, max+1),
}
}
@ -22,17 +30,17 @@ func newPatriciaTreeString(strs ...string) *patriciaTree {
for i, s := range strs {
b[i] = []byte(s)
}
return &patriciaTree{
root: newNode(b),
}
return newPatriciaTree(b...)
}
func (t *patriciaTree) matchPrefix(r io.Reader) bool {
return t.root.match(r, true)
n, _ := io.ReadFull(r, t.buf)
return t.root.match(t.buf[:n], true)
}
func (t *patriciaTree) match(r io.Reader) bool {
return t.root.match(r, false)
n, _ := io.ReadFull(r, t.buf)
return t.root.match(t.buf[:n], false)
}
type ptNode struct {
@ -122,52 +130,30 @@ func splitPrefix(bss [][]byte) (prefix []byte, rest [][]byte) {
return prefix, rest
}
func readBytes(r io.Reader, n int) (b []byte, err error) {
b = make([]byte, n)
o := 0
for o < n {
nr, err := r.Read(b[o:])
if err != nil && err != io.EOF {
return b, err
func (n *ptNode) match(b []byte, prefix bool) bool {
l := len(n.prefix)
if l > 0 {
if l > len(b) {
l = len(b)
}
o += nr
if err == io.EOF {
break
}
}
return b[:o], nil
}
func (n *ptNode) match(r io.Reader, prefix bool) bool {
if l := len(n.prefix); l > 0 {
b, err := readBytes(r, l)
if err != nil || len(b) != l || !bytes.Equal(b, n.prefix) {
if !bytes.Equal(b[:l], n.prefix) {
return false
}
}
if prefix && n.terminal {
if n.terminal && (prefix || len(n.prefix) == len(b)) {
return true
}
b := make([]byte, 1)
for {
nr, err := r.Read(b)
if nr != 0 {
break
}
if err == io.EOF {
return n.terminal
}
if err != nil {
nextN, ok := n.next[b[l]]
if !ok {
return false
}
}
nextN, ok := n.next[b[0]]
return ok && nextN.match(r, prefix)
if l == len(b) {
b = b[l:l]
} else {
b = b[l+1:]
}
return nextN.match(b, prefix)
}