mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-29 21:15:39 +00:00
7c1d6e35a5
Updates #11058 Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
412 lines
12 KiB
Go
412 lines
12 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
|
|
package art
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"math/rand"
|
|
"net/netip"
|
|
"runtime"
|
|
"sort"
|
|
"strings"
|
|
"testing"
|
|
|
|
"github.com/google/go-cmp/cmp"
|
|
)
|
|
|
|
func TestInversePrefix(t *testing.T) {
|
|
t.Parallel()
|
|
for i := range 256 {
|
|
for len := 0; len < 9; len++ {
|
|
addr := i & (0xFF << (8 - len))
|
|
idx := prefixIndex(uint8(addr), len)
|
|
addr2, len2 := inversePrefixIndex(idx)
|
|
if addr2 != uint8(addr) || len2 != len {
|
|
t.Errorf("inverse(index(%d/%d)) != %d/%d", addr, len, addr2, len2)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestHostIndex(t *testing.T) {
|
|
t.Parallel()
|
|
for i := range 256 {
|
|
got := hostIndex(uint8(i))
|
|
want := prefixIndex(uint8(i), 8)
|
|
if got != want {
|
|
t.Errorf("hostIndex(%d) = %d, want %d", i, got, want)
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestStrideTableInsert(t *testing.T) {
|
|
t.Parallel()
|
|
// Verify that strideTable's lookup results after a bunch of inserts exactly
|
|
// match those of a naive implementation that just scans all prefixes on
|
|
// every lookup. The naive implementation is very slow, but its behavior is
|
|
// easy to verify by inspection.
|
|
|
|
pfxs := shufflePrefixes(allPrefixes())[:100]
|
|
slow := slowTable[int]{pfxs}
|
|
fast := strideTable[int]{}
|
|
|
|
if debugStrideInsert {
|
|
t.Logf("slow table:\n%s", slow.String())
|
|
}
|
|
|
|
for _, pfx := range pfxs {
|
|
fast.insert(pfx.addr, pfx.len, pfx.val)
|
|
if debugStrideInsert {
|
|
t.Logf("after insert %d/%d:\n%s", pfx.addr, pfx.len, fast.tableDebugString())
|
|
}
|
|
}
|
|
|
|
for i := range 256 {
|
|
addr := uint8(i)
|
|
slowVal, slowOK := slow.get(addr)
|
|
fastVal, fastOK := fast.get(addr)
|
|
if !getsEqual(fastVal, fastOK, slowVal, slowOK) {
|
|
t.Fatalf("strideTable.get(%d) = (%v, %v), want (%v, %v)", addr, fastVal, fastOK, slowVal, slowOK)
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestStrideTableInsertShuffled(t *testing.T) {
|
|
t.Parallel()
|
|
// The order in which routes are inserted into a route table does not
|
|
// influence the final shape of the table, as long as the same set of
|
|
// prefixes is being inserted. This test verifies that strideTable behaves
|
|
// this way.
|
|
//
|
|
// In addition to the basic shuffle test, we also check that this behavior
|
|
// is maintained if all inserted routes have the same value pointer. This
|
|
// shouldn't matter (the strideTable still needs to correctly account for
|
|
// each inserted route, regardless of associated value), but during initial
|
|
// development a subtle bug made the table corrupt itself in that setup, so
|
|
// this test includes a regression test for that.
|
|
|
|
routes := shufflePrefixes(allPrefixes())[:100]
|
|
|
|
zero := 0
|
|
rt := strideTable[int]{}
|
|
// strideTable has a value interface, but internally has to keep
|
|
// track of distinct routes even if they all have the same
|
|
// value. rtZero uses the same value for all routes, and expects
|
|
// correct behavior.
|
|
rtZero := strideTable[int]{}
|
|
for _, route := range routes {
|
|
rt.insert(route.addr, route.len, route.val)
|
|
rtZero.insert(route.addr, route.len, zero)
|
|
}
|
|
|
|
// Order of insertion should not affect the final shape of the stride table.
|
|
routes2 := append([]slowEntry[int](nil), routes...) // dup so we can print both slices on fail
|
|
for range 100 {
|
|
rand.Shuffle(len(routes2), func(i, j int) { routes2[i], routes2[j] = routes2[j], routes2[i] })
|
|
rt2 := strideTable[int]{}
|
|
for _, route := range routes2 {
|
|
rt2.insert(route.addr, route.len, route.val)
|
|
}
|
|
if diff := cmp.Diff(rt.tableDebugString(), rt2.tableDebugString()); diff != "" {
|
|
t.Errorf("tables ended up different with different insertion order (-got+want):\n%s\n\nOrder 1: %v\nOrder 2: %v", diff, formatSlowEntriesShort(routes), formatSlowEntriesShort(routes2))
|
|
}
|
|
|
|
rtZero2 := strideTable[int]{}
|
|
for _, route := range routes2 {
|
|
rtZero2.insert(route.addr, route.len, zero)
|
|
}
|
|
if diff := cmp.Diff(rtZero.tableDebugString(), rtZero2.tableDebugString(), cmpDiffOpts...); diff != "" {
|
|
t.Errorf("tables with identical vals ended up different with different insertion order (-got+want):\n%s\n\nOrder 1: %v\nOrder 2: %v", diff, formatSlowEntriesShort(routes), formatSlowEntriesShort(routes2))
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestStrideTableDelete(t *testing.T) {
|
|
t.Parallel()
|
|
// Compare route deletion to our reference slowTable.
|
|
pfxs := shufflePrefixes(allPrefixes())[:100]
|
|
slow := slowTable[int]{pfxs}
|
|
fast := strideTable[int]{}
|
|
|
|
if debugStrideDelete {
|
|
t.Logf("slow table:\n%s", slow.String())
|
|
}
|
|
|
|
for _, pfx := range pfxs {
|
|
fast.insert(pfx.addr, pfx.len, pfx.val)
|
|
if debugStrideDelete {
|
|
t.Logf("after insert %d/%d:\n%s", pfx.addr, pfx.len, fast.tableDebugString())
|
|
}
|
|
}
|
|
|
|
toDelete := pfxs[:50]
|
|
for _, pfx := range toDelete {
|
|
slow.delete(pfx.addr, pfx.len)
|
|
fast.delete(pfx.addr, pfx.len)
|
|
}
|
|
|
|
// Sanity check that slowTable seems to have done the right thing.
|
|
if cnt := len(slow.prefixes); cnt != 50 {
|
|
t.Fatalf("slowTable has %d entries after deletes, want 50", cnt)
|
|
}
|
|
|
|
for i := range 256 {
|
|
addr := uint8(i)
|
|
slowVal, slowOK := slow.get(addr)
|
|
fastVal, fastOK := fast.get(addr)
|
|
if !getsEqual(fastVal, fastOK, slowVal, slowOK) {
|
|
t.Fatalf("strideTable.get(%d) = (%v, %v), want (%v, %v)", addr, fastVal, fastOK, slowVal, slowOK)
|
|
}
|
|
}
|
|
}
|
|
|
|
func TestStrideTableDeleteShuffle(t *testing.T) {
|
|
t.Parallel()
|
|
// Same as TestStrideTableInsertShuffle, the order in which prefixes are
|
|
// deleted should not impact the final shape of the route table.
|
|
|
|
routes := shufflePrefixes(allPrefixes())[:100]
|
|
toDelete := routes[:50]
|
|
|
|
zero := 0
|
|
rt := strideTable[int]{}
|
|
// strideTable has a value interface, but internally has to keep
|
|
// track of distinct routes even if they all have the same
|
|
// value. rtZero uses the same value for all routes, and expects
|
|
// correct behavior.
|
|
rtZero := strideTable[int]{}
|
|
for _, route := range routes {
|
|
rt.insert(route.addr, route.len, route.val)
|
|
rtZero.insert(route.addr, route.len, zero)
|
|
}
|
|
for _, route := range toDelete {
|
|
rt.delete(route.addr, route.len)
|
|
rtZero.delete(route.addr, route.len)
|
|
}
|
|
|
|
// Order of deletion should not affect the final shape of the stride table.
|
|
toDelete2 := append([]slowEntry[int](nil), toDelete...) // dup so we can print both slices on fail
|
|
for range 100 {
|
|
rand.Shuffle(len(toDelete2), func(i, j int) { toDelete2[i], toDelete2[j] = toDelete2[j], toDelete2[i] })
|
|
rt2 := strideTable[int]{}
|
|
for _, route := range routes {
|
|
rt2.insert(route.addr, route.len, route.val)
|
|
}
|
|
for _, route := range toDelete2 {
|
|
rt2.delete(route.addr, route.len)
|
|
}
|
|
if diff := cmp.Diff(rt.tableDebugString(), rt2.tableDebugString(), cmpDiffOpts...); diff != "" {
|
|
t.Errorf("tables ended up different with different deletion order (-got+want):\n%s\n\nOrder 1: %v\nOrder 2: %v", diff, formatSlowEntriesShort(toDelete), formatSlowEntriesShort(toDelete2))
|
|
}
|
|
|
|
rtZero2 := strideTable[int]{}
|
|
for _, route := range routes {
|
|
rtZero2.insert(route.addr, route.len, zero)
|
|
}
|
|
for _, route := range toDelete2 {
|
|
rtZero2.delete(route.addr, route.len)
|
|
}
|
|
if diff := cmp.Diff(rtZero.tableDebugString(), rtZero2.tableDebugString(), cmpDiffOpts...); diff != "" {
|
|
t.Errorf("tables with identical vals ended up different with different deletion order (-got+want):\n%s\n\nOrder 1: %v\nOrder 2: %v", diff, formatSlowEntriesShort(toDelete), formatSlowEntriesShort(toDelete2))
|
|
}
|
|
}
|
|
}
|
|
|
|
var strideRouteCount = []int{10, 50, 100, 200}
|
|
|
|
// forCountAndOrdering runs the benchmark fn with different sets of routes.
|
|
//
|
|
// fn is called once for each combination of {num_routes, order}, where
|
|
// num_routes is the values in strideRouteCount, and order is the order of the
|
|
// routes in the list: random, largest prefix first (/0 to /8), and smallest
|
|
// prefix first (/8 to /0).
|
|
func forStrideCountAndOrdering(b *testing.B, fn func(b *testing.B, routes []slowEntry[int])) {
|
|
routes := shufflePrefixes(allPrefixes())
|
|
for _, nroutes := range strideRouteCount {
|
|
b.Run(fmt.Sprint(nroutes), func(b *testing.B) {
|
|
runAndRecord := func(b *testing.B) {
|
|
b.ReportAllocs()
|
|
var startMem, endMem runtime.MemStats
|
|
runtime.ReadMemStats(&startMem)
|
|
fn(b, routes)
|
|
runtime.ReadMemStats(&endMem)
|
|
ops := float64(b.N) * float64(len(routes))
|
|
allocs := float64(endMem.Mallocs - startMem.Mallocs)
|
|
bytes := float64(endMem.TotalAlloc - startMem.TotalAlloc)
|
|
b.ReportMetric(roundFloat64(allocs/ops), "allocs/op")
|
|
b.ReportMetric(roundFloat64(bytes/ops), "B/op")
|
|
}
|
|
|
|
routes := append([]slowEntry[int](nil), routes[:nroutes]...)
|
|
b.Run("random_order", runAndRecord)
|
|
sort.Slice(routes, func(i, j int) bool {
|
|
if routes[i].len < routes[j].len {
|
|
return true
|
|
}
|
|
return routes[i].addr < routes[j].addr
|
|
})
|
|
b.Run("largest_first", runAndRecord)
|
|
sort.Slice(routes, func(i, j int) bool {
|
|
if routes[j].len < routes[i].len {
|
|
return true
|
|
}
|
|
return routes[j].addr < routes[i].addr
|
|
})
|
|
b.Run("smallest_first", runAndRecord)
|
|
})
|
|
}
|
|
}
|
|
|
|
func BenchmarkStrideTableInsertion(b *testing.B) {
|
|
forStrideCountAndOrdering(b, func(b *testing.B, routes []slowEntry[int]) {
|
|
val := 0
|
|
for range b.N {
|
|
var rt strideTable[int]
|
|
for _, route := range routes {
|
|
rt.insert(route.addr, route.len, val)
|
|
}
|
|
}
|
|
inserts := float64(b.N) * float64(len(routes))
|
|
elapsed := float64(b.Elapsed().Nanoseconds())
|
|
elapsedSec := b.Elapsed().Seconds()
|
|
b.ReportMetric(elapsed/inserts, "ns/op")
|
|
b.ReportMetric(inserts/elapsedSec, "routes/s")
|
|
})
|
|
}
|
|
|
|
func BenchmarkStrideTableDeletion(b *testing.B) {
|
|
forStrideCountAndOrdering(b, func(b *testing.B, routes []slowEntry[int]) {
|
|
val := 0
|
|
var rt strideTable[int]
|
|
for _, route := range routes {
|
|
rt.insert(route.addr, route.len, val)
|
|
}
|
|
|
|
b.ResetTimer()
|
|
for range b.N {
|
|
rt2 := rt
|
|
for _, route := range routes {
|
|
rt2.delete(route.addr, route.len)
|
|
}
|
|
}
|
|
deletes := float64(b.N) * float64(len(routes))
|
|
elapsed := float64(b.Elapsed().Nanoseconds())
|
|
elapsedSec := b.Elapsed().Seconds()
|
|
b.ReportMetric(elapsed/deletes, "ns/op")
|
|
b.ReportMetric(deletes/elapsedSec, "routes/s")
|
|
})
|
|
}
|
|
|
|
var writeSink int
|
|
|
|
func BenchmarkStrideTableGet(b *testing.B) {
|
|
// No need to forCountAndOrdering here, route lookup time is independent of
|
|
// the route count.
|
|
routes := shufflePrefixes(allPrefixes())[:100]
|
|
var rt strideTable[int]
|
|
for _, route := range routes {
|
|
rt.insert(route.addr, route.len, route.val)
|
|
}
|
|
|
|
b.ResetTimer()
|
|
for i := range b.N {
|
|
writeSink, _ = rt.get(uint8(i))
|
|
}
|
|
gets := float64(b.N)
|
|
elapsedSec := b.Elapsed().Seconds()
|
|
b.ReportMetric(gets/elapsedSec, "routes/s")
|
|
}
|
|
|
|
// slowTable is an 8-bit routing table implemented as a set of prefixes that are
|
|
// explicitly scanned in full for every route lookup. It is very slow, but also
|
|
// reasonably easy to verify by inspection, and so a good comparison target for
|
|
// strideTable.
|
|
type slowTable[T any] struct {
|
|
prefixes []slowEntry[T]
|
|
}
|
|
|
|
type slowEntry[T any] struct {
|
|
addr uint8
|
|
len int
|
|
val T
|
|
}
|
|
|
|
func (t *slowTable[T]) String() string {
|
|
pfxs := append([]slowEntry[T](nil), t.prefixes...)
|
|
sort.Slice(pfxs, func(i, j int) bool {
|
|
if pfxs[i].len != pfxs[j].len {
|
|
return pfxs[i].len < pfxs[j].len
|
|
}
|
|
return pfxs[i].addr < pfxs[j].addr
|
|
})
|
|
var ret bytes.Buffer
|
|
for _, pfx := range pfxs {
|
|
fmt.Fprintf(&ret, "%3d/%d (%08b/%08b) = %v\n", pfx.addr, pfx.len, pfx.addr, pfxMask(pfx.len), pfx.val)
|
|
}
|
|
return ret.String()
|
|
}
|
|
|
|
func (t *slowTable[T]) delete(addr uint8, prefixLen int) {
|
|
pfx := make([]slowEntry[T], 0, len(t.prefixes))
|
|
for _, e := range t.prefixes {
|
|
if e.addr == addr && e.len == prefixLen {
|
|
continue
|
|
}
|
|
pfx = append(pfx, e)
|
|
}
|
|
t.prefixes = pfx
|
|
}
|
|
|
|
func (t *slowTable[T]) get(addr uint8) (ret T, ok bool) {
|
|
var curLen = -1
|
|
for _, e := range t.prefixes {
|
|
if addr&pfxMask(e.len) == e.addr && e.len >= curLen {
|
|
ret = e.val
|
|
curLen = e.len
|
|
}
|
|
}
|
|
return ret, curLen != -1
|
|
}
|
|
|
|
func pfxMask(pfxLen int) uint8 {
|
|
return 0xFF << (8 - pfxLen)
|
|
}
|
|
|
|
func allPrefixes() []slowEntry[int] {
|
|
ret := make([]slowEntry[int], 0, lastHostIndex)
|
|
for i := 1; i < lastHostIndex+1; i++ {
|
|
a, l := inversePrefixIndex(i)
|
|
ret = append(ret, slowEntry[int]{a, l, i})
|
|
}
|
|
return ret
|
|
}
|
|
|
|
func shufflePrefixes(pfxs []slowEntry[int]) []slowEntry[int] {
|
|
rand.Shuffle(len(pfxs), func(i, j int) { pfxs[i], pfxs[j] = pfxs[j], pfxs[i] })
|
|
return pfxs
|
|
}
|
|
|
|
func formatSlowEntriesShort[T any](ents []slowEntry[T]) string {
|
|
var ret []string
|
|
for _, ent := range ents {
|
|
ret = append(ret, fmt.Sprintf("%d/%d", ent.addr, ent.len))
|
|
}
|
|
return "[" + strings.Join(ret, " ") + "]"
|
|
}
|
|
|
|
var cmpDiffOpts = []cmp.Option{
|
|
cmp.Comparer(func(a, b netip.Prefix) bool { return a == b }),
|
|
}
|
|
|
|
func getsEqual[T comparable](a T, aOK bool, b T, bOK bool) bool {
|
|
if !aOK && !bOK {
|
|
return true
|
|
}
|
|
if aOK != bOK {
|
|
return false
|
|
}
|
|
return a == b
|
|
}
|