eth/peerstats: bump MinLatencySamples from 10 to 100

Require substantially more samples before a peer's request-latency EMA
becomes eligible for protection. A 10-sample floor was too low: a peer
hitting 10 fast replies in a short burst could earn protection before
the slow alpha=0.01 EMA had moved meaningfully away from the bootstrap
value. At ~70-sample EMA half-life, a 100-sample floor means the EMA
has been refined through several half-lives before it can affect
dropping decisions.

Updates the dropper tests that previously used RequestSamples=50 to
use peerstats.MinLatencySamples so they stay robust to future value
changes. Design notes and a test comment reference the new value.

eth/dropper_test.go

@@ -243,15 +243,15 @@ func TestProtectedByPoolRequestLatencyBasic(t *testing.T) {
 	// Three peers have enough samples; the two fastest should win.
 	stats[dialed[0].ID().String()] = peerstats.PeerStats{
 		RequestLatencyEMA: 50 * time.Millisecond,
-		RequestSamples:    50,
+		RequestSamples:    peerstats.MinLatencySamples,
 	}
 	stats[dialed[1].ID().String()] = peerstats.PeerStats{
 		RequestLatencyEMA: 100 * time.Millisecond,
-		RequestSamples:    50,
+		RequestSamples:    peerstats.MinLatencySamples,
 	}
 	stats[dialed[2].ID().String()] = peerstats.PeerStats{
 		RequestLatencyEMA: 2 * time.Second,
-		RequestSamples:    50,
+		RequestSamples:    peerstats.MinLatencySamples,
 	}
 
 	protected := protectedPeersByPool(nil, dialed, stats)
@@ -313,7 +313,7 @@ func TestProtectedByPoolRequestLatencyPerPool(t *testing.T) {
 	for _, p := range inbound {
 		stats[p.ID().String()] = peerstats.PeerStats{
 			RequestLatencyEMA: 50 * time.Millisecond,
-			RequestSamples:    50,
+			RequestSamples:    peerstats.MinLatencySamples,
 		}
 	}
 	// Dialed peers are slower (1s) — globally they would all lose, but
@@ -321,7 +321,7 @@ func TestProtectedByPoolRequestLatencyPerPool(t *testing.T) {
 	for _, p := range dialed {
 		stats[p.ID().String()] = peerstats.PeerStats{
 			RequestLatencyEMA: 1 * time.Second,
-			RequestSamples:    50,
+			RequestSamples:    peerstats.MinLatencySamples,
 		}
 	}
 

eth/peerstats/peerstats.go

@@ -52,7 +52,7 @@ const (
 	// MinLatencySamples is the number of latency samples a peer must accumulate
 	// before its RequestLatencyEMA is considered meaningful for protection.
 	// Prevents a single lucky-fast reply from displacing established peers.
-	MinLatencySamples = 10
+	MinLatencySamples = 100
 )
 
 // PeerStats is the exported per-peer snapshot returned by GetAllPeerStats.

eth/peerstats/peerstats_test.go

@@ -181,7 +181,7 @@ func TestNotifyPeerDropClearsStats(t *testing.T) {
 
 // TestStaleRequestLatencyAfterDrop documents the accepted behavior: a
 // late sample after NotifyPeerDrop recreates a 1-sample entry. The
-// dropper's MinLatencySamples=10 guard ensures this is harmless.
+// dropper's MinLatencySamples=100 guard ensures this is harmless.
 func TestStaleRequestLatencyAfterDrop(t *testing.T) {
 	s := New()
 	s.NotifyRequestLatency("peerA", 200*time.Millisecond)