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7149155b80
Make Linux parsePorts also an append-style API and attach it to
caller's provided append base memory.
And add a little string intern pool in front of the []byte to string
for inode names.
name old time/op new time/op delta
GetList-8 11.1ms ± 4% 9.8ms ± 6% -11.68% (p=0.000 n=9+10)
name old alloc/op new alloc/op delta
GetList-8 92.8kB ± 2% 79.7kB ± 0% -14.11% (p=0.000 n=10+9)
name old allocs/op new allocs/op delta
GetList-8 2.94k ± 1% 2.76k ± 0% -6.16% (p=0.000 n=10+10)
More coming. (the bulk of the allocations are in addProcesses and
filesystem operations, most of which we should usually be able to
skip)
Updates #5958
Change-Id: I3f0c03646d314a16fef7f8346aefa7d5c96701e7
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
118 lines
2.3 KiB
Go
118 lines
2.3 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package portlist
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import (
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"fmt"
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"sort"
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"strings"
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"tailscale.com/envknob"
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)
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// Port is a listening port on the machine.
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type Port struct {
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Proto string // "tcp" or "udp"
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Port uint16 // port number
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Process string // optional process name, if found
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inode string // OS-specific; "socket:[165614651]" on Linux
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}
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// List is a list of Ports.
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type List []Port
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func (a *Port) lessThan(b *Port) bool {
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if a.Port < b.Port {
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return true
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} else if a.Port > b.Port {
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return false
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}
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if a.Proto < b.Proto {
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return true
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} else if a.Proto > b.Proto {
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return false
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}
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if a.inode < b.inode {
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return true
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} else if a.inode > b.inode {
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return false
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}
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if a.Process < b.Process {
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return true
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} else if a.Process > b.Process {
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return false
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}
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return false
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}
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func (a List) sameInodes(b List) bool {
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if len(a) != len(b) {
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return false
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}
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for i := range a {
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if a[i].Proto != b[i].Proto ||
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a[i].Port != b[i].Port ||
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a[i].inode != b[i].inode {
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return false
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}
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}
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return true
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}
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func (pl List) String() string {
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var sb strings.Builder
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for _, v := range pl {
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fmt.Fprintf(&sb, "%-3s %5d %-17s %#v\n",
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v.Proto, v.Port, v.inode, v.Process)
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}
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return strings.TrimRight(sb.String(), "\n")
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}
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var debugDisablePortlist = envknob.RegisterBool("TS_DEBUG_DISABLE_PORTLIST")
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func (p *Poller) getList() (List, error) {
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if debugDisablePortlist() {
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return nil, nil
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}
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var err error
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p.scratch, err = appendListeningPorts(p.scratch[:0])
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if err != nil {
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return nil, fmt.Errorf("listPorts: %s", err)
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}
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pl := sortAndDedup(p.scratch)
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if pl.sameInodes(p.prev) {
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// Nothing changed, skip inode lookup
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return p.prev, nil
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}
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pl, err = addProcesses(pl)
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if err != nil {
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return nil, fmt.Errorf("addProcesses: %s", err)
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}
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return pl, nil
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}
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// sortAndDedup sorts ps in place (by Port.lessThan) and then returns
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// a subset of it with duplicate (Proto, Port) removed.
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func sortAndDedup(ps List) List {
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sort.Slice(ps, func(i, j int) bool {
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return (&ps[i]).lessThan(&ps[j])
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})
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out := ps[:0]
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var last Port
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for _, p := range ps {
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protoPort := Port{Proto: p.Proto, Port: p.Port}
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if last == protoPort {
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continue
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}
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out = append(out, p)
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last = protoPort
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}
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return out
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}
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