performance: remove significant overhead of decaymap (#1420)

I have ~5% base CPU load on an idle server due to mutex 100x per second.

Signed-off-by: Matthias Dötsch <matze@mdoetsch.de>

Author: brainexe

decaymap/decaymap.go

@@ -146,7 +146,7 @@ func (m *Impl[K, V]) Close() {
 func (m *Impl[K, V]) cleanupWorker() {
 	defer m.wg.Done()
 	batch := make([]deleteReq[K], 0, 64)
-	ticker := time.NewTicker(10 * time.Millisecond)
+	ticker := time.NewTicker(500 * time.Millisecond)
 	defer ticker.Stop()
 
 	flush := func() {

decaymap/decaymap_test.go

@@ -32,7 +32,7 @@ func TestImpl(t *testing.T) {
 
 	// Deletion of expired entries after Get is deferred to a background worker.
 	// Assert it eventually disappears from the map.
-	deadline := time.Now().Add(200 * time.Millisecond)
+	deadline := time.Now().Add(700 * time.Millisecond)
 	for time.Now().Before(deadline) {
 		if dm.Len() == 0 {
 			break

docs/docs/CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add iplist2rule tool that lets admins turn an IP address blocklist into an Anubis ruleset.
 - Add Polish locale ([#1292](https://github.com/TecharoHQ/anubis/pull/1309))
 - Fix honeypot and imprint links missing `BASE_PREFIX` when deployed behind a path prefix ([#1402](https://github.com/TecharoHQ/anubis/issues/1402))
+- Improve idle performance in memory storage
 
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