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derp/derpserver: collapse clients and clientsAtomic into one hashtriemap

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Server.clientsAtomic was introduced in 6b729795c3 as a lock-free
mirror of Server.clients to skip Server.mu on the packet send hot
path. This drops the non-concurrent map and makes all the existing
callers of the old plain map just use the concurrent map, but still
holding Server.mu.

BenchmarkLookupDestHashTrie is unchanged at ~2ns/op.

Fixes #19726

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I0894e4d86914d152b9b5fef969a3184bcb96f678
This commit is contained in:
Brad Fitzpatrick
2026-05-13 16:43:37 +00:00
committed by Brad Fitzpatrick
parent 4d68493144
commit dc323b1351
2 changed files with 77 additions and 106 deletions
Download Patch File Download Diff File Expand all files Collapse all files
derp/derpserver/derpserver_test.go
+29 -49
View File
@@ -29,7 +29,6 @@ import (
"golang.org/x/time/rate"
"tailscale.com/derp"
"tailscale.com/derp/derpconst"
"tailscale.com/envknob"
"tailscale.com/tstime"
"tailscale.com/types/key"
"tailscale.com/types/logger"
@@ -150,7 +149,6 @@ func pubAll(b byte) (ret key.NodePublic) {
func TestForwarderRegistration(t *testing.T) {
s := &Server{
clients: make(map[key.NodePublic]*clientSet),
clientsMesh: map[key.NodePublic]PacketForwarder{},
}
want := func(want map[key.NodePublic]PacketForwarder) {
@@ -232,7 +230,7 @@ func TestForwarderRegistration(t *testing.T) {
key: u1,
logf: logger.Discard,
}
s.clients[u1] = singleClient(u1c)
s.clients.Store(u1, singleClient(u1c))
s.RemovePacketForwarder(u1, testFwd(100))
want(map[key.NodePublic]PacketForwarder{
u1: nil,
@@ -252,7 +250,7 @@ func TestForwarderRegistration(t *testing.T) {
// Now pretend u1 was already connected locally (so clientsMesh[u1] is nil), and then we heard
// that they're also connected to a peer of ours. That shouldn't transition the forwarder
// from nil to the new one, not a multiForwarder.
s.clients[u1] = singleClient(u1c)
s.clients.Store(u1, singleClient(u1c))
s.clientsMesh[u1] = nil
want(map[key.NodePublic]PacketForwarder{
u1: nil,
@@ -284,7 +282,6 @@ func TestMultiForwarder(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
s := &Server{
clients: make(map[key.NodePublic]*clientSet),
clientsMesh: map[key.NodePublic]PacketForwarder{},
}
u := pubAll(1)
@@ -393,7 +390,7 @@ func TestServerDupClients(t *testing.T) {
}
wantSingleClient := func(t *testing.T, want *sclient) {
t.Helper()
got, ok := s.clients[want.key]
got, ok := s.clients.Load(want.key)
if !ok {
t.Error("no clients for key")
return
@@ -416,7 +413,7 @@ func TestServerDupClients(t *testing.T) {
}
wantNoClient := func(t *testing.T) {
t.Helper()
_, ok := s.clients[clientPub]
_, ok := s.clients.Load(clientPub)
if !ok {
// Good
return
@@ -425,7 +422,7 @@ func TestServerDupClients(t *testing.T) {
}
wantDupSet := func(t *testing.T) *dupClientSet {
t.Helper()
cs, ok := s.clients[clientPub]
cs, ok := s.clients.Load(clientPub)
if !ok {
t.Fatal("no set for key; want dup set")
return nil
@@ -438,7 +435,7 @@ func TestServerDupClients(t *testing.T) {
}
wantActive := func(t *testing.T, want *sclient) {
t.Helper()
set, ok := s.clients[clientPub]
set, ok := s.clients.Load(clientPub)
if !ok {
t.Error("no set for key")
return
@@ -779,7 +776,7 @@ func TestServeDebugTrafficUniqueSenders(t *testing.T) {
s.mu.Lock()
cs := &clientSet{}
cs.activeClient.Store(c)
s.clients[clientKey] = cs
s.clients.Store(clientKey, cs)
s.mu.Unlock()
estimate := c.EstimatedUniqueSenders()
@@ -1192,7 +1189,7 @@ func TestUpdateRateLimits(t *testing.T) {
cs.activeClient.Store(c)
s.mu.Lock()
s.clients[clientKey] = cs
s.clients.Store(clientKey, cs)
s.mu.Unlock()
rc := RateConfig{
@@ -1245,7 +1242,7 @@ func TestUpdateRateLimits(t *testing.T) {
meshCS.activeClient.Store(meshClient)
s.mu.Lock()
s.clients[meshKey] = meshCS
s.clients.Store(meshKey, meshCS)
s.mu.Unlock()
rc = RateConfig{
@@ -1272,7 +1269,7 @@ func TestUpdateRateLimits(t *testing.T) {
dupCS.activeClient.Store(d1)
dupCS.dup = &dupClientSet{set: set.Of(d1, d2)}
s.mu.Lock()
s.clients[dupKey] = dupCS
s.clients.Store(dupKey, dupCS)
s.mu.Unlock()
rc = RateConfig{
@@ -1364,7 +1361,7 @@ func TestLoadAndApplyRateConfig(t *testing.T) {
cs := &clientSet{}
cs.activeClient.Store(c)
s.mu.Lock()
s.clients[clientKey] = cs
s.clients.Store(clientKey, cs)
s.mu.Unlock()
f := writeConfig(t, fmt.Sprintf(`{"PerClientRateLimitBytesPerSec": %d, "PerClientRateBurstBytes": %d}`,
@@ -1447,19 +1444,8 @@ func TestLoadAndApplyRateConfig(t *testing.T) {
})
}
const peerHashTrieDisableEnv = "TS_DEBUG_DERP_DISABLE_PEER_HASHTRIE"
func setPeerHashTrieDisabled(tb testing.TB, disabled bool) {
tb.Helper()
envknob.Setenv(peerHashTrieDisableEnv, fmt.Sprint(disabled))
tb.Cleanup(func() { envknob.Setenv(peerHashTrieDisableEnv, "") })
}
func TestLookupDestHashTrieFastPath(t *testing.T) {
setPeerHashTrieDisabled(t, false)
s := &Server{
clients: map[key.NodePublic]*clientSet{},
clientsMesh: map[key.NodePublic]PacketForwarder{},
clock: tstime.StdClock{},
}
@@ -1468,8 +1454,7 @@ func TestLookupDestHashTrieFastPath(t *testing.T) {
dstClient := &sclient{key: dst}
cs := &clientSet{}
cs.activeClient.Store(dstClient)
s.clients[dst] = cs
s.clientsAtomic.Store(dst, cs)
s.clients.Store(dst, cs)
c := &sclient{s: s, key: src}
got, fwd, dstLen := c.lookupDest(dst)
@@ -1488,10 +1473,7 @@ func TestLookupDestHashTrieFastPath(t *testing.T) {
}
func TestLookupDestHashTrieFallsBackForForwarder(t *testing.T) {
setPeerHashTrieDisabled(t, false)
s := &Server{
clients: map[key.NodePublic]*clientSet{},
clientsMesh: map[key.NodePublic]PacketForwarder{},
clock: tstime.StdClock{},
}
@@ -1506,11 +1488,8 @@ func TestLookupDestHashTrieFallsBackForForwarder(t *testing.T) {
}
}
func TestLookupDestHashTrieIgnoresInactiveStaleSet(t *testing.T) {
setPeerHashTrieDisabled(t, false)
func TestLookupDestHashTrieIgnoresInactiveSet(t *testing.T) {
s := &Server{
clients: map[key.NodePublic]*clientSet{},
clientsMesh: map[key.NodePublic]PacketForwarder{},
clock: tstime.StdClock{},
}
@@ -1518,24 +1497,28 @@ func TestLookupDestHashTrieIgnoresInactiveStaleSet(t *testing.T) {
dst := pubAll(2)
c := &sclient{s: s, key: src}
s.clientsAtomic.Store(dst, &clientSet{})
newClient := &sclient{key: dst}
newSet := &clientSet{}
newSet.activeClient.Store(newClient)
s.clients[dst] = newSet
// A clientSet with no activeClient (a transient state during
// register/unregister) must not be returned by the fast path.
cs := &clientSet{}
s.clients.Store(dst, cs)
got, fwd, dstLen := c.lookupDest(dst)
if got != nil || fwd != nil || dstLen != 0 {
t.Fatalf("lookupDest with inactive set = (%v, %v, %d), want (nil, nil, 0)", got, fwd, dstLen)
}
// Setting activeClient on the same in-map entry must make the next
// fast-path lookup observe it.
newClient := &sclient{key: dst}
cs.activeClient.Store(newClient)
got, fwd, dstLen = c.lookupDest(dst)
if got != newClient || fwd != nil || dstLen != 1 {
t.Fatalf("lookupDest = (%v, %v, %d), want (%v, nil, 1)", got, fwd, dstLen, newClient)
t.Fatalf("lookupDest after activation = (%v, %v, %d), want (%v, nil, 1)", got, fwd, dstLen, newClient)
}
}
func TestLookupDestHashTrieNoAlloc(t *testing.T) {
setPeerHashTrieDisabled(t, false)
s := &Server{
clients: map[key.NodePublic]*clientSet{},
clientsMesh: map[key.NodePublic]PacketForwarder{},
clock: tstime.StdClock{},
}
@@ -1546,8 +1529,7 @@ func TestLookupDestHashTrieNoAlloc(t *testing.T) {
dstClients[i] = &sclient{key: dstKeys[i]}
cs := &clientSet{}
cs.activeClient.Store(dstClients[i])
s.clients[dstKeys[i]] = cs
s.clientsAtomic.Store(dstKeys[i], cs)
s.clients.Store(dstKeys[i], cs)
}
c := &sclient{s: s, key: pubAll(1)}
@@ -1568,7 +1550,6 @@ func TestLookupDestHashTrieNoAlloc(t *testing.T) {
func BenchmarkLookupDestHashTrie(b *testing.B) {
s := &Server{
clients: map[key.NodePublic]*clientSet{},
clientsMesh: map[key.NodePublic]PacketForwarder{},
clock: tstime.StdClock{},
}
@@ -1579,8 +1560,7 @@ func BenchmarkLookupDestHashTrie(b *testing.B) {
dstClients[i] = &sclient{key: dstKeys[i]}
cs := &clientSet{}
cs.activeClient.Store(dstClients[i])
s.clients[dstKeys[i]] = cs
s.clientsAtomic.Store(dstKeys[i], cs)
s.clients.Store(dstKeys[i], cs)
}
b.ReportAllocs()