Merge pull request #20678 from karalabe/broadcast-sqrt-proper

eth: don't enforce minimum broadcast, fix broadcast test

eth/handler.go

@@ -50,9 +50,6 @@ const (
 	// txChanSize is the size of channel listening to NewTxsEvent.
 	// The number is referenced from the size of tx pool.
 	txChanSize = 4096
-
-	// minimim number of peers to broadcast entire blocks and transactions too.
-	minBroadcastPeers = 4
 )
 
 var (
@@ -830,14 +827,7 @@ func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) {
 			return
 		}
 		// Send the block to a subset of our peers
-		transferLen := int(math.Sqrt(float64(len(peers))))
-		if transferLen < minBroadcastPeers {
-			transferLen = minBroadcastPeers
-		}
-		if transferLen > len(peers) {
-			transferLen = len(peers)
-		}
-		transfer := peers[:transferLen]
+		transfer := peers[:int(math.Sqrt(float64(len(peers))))]
 		for _, peer := range transfer {
 			peer.AsyncSendNewBlock(block, td)
 		}
@@ -866,14 +856,7 @@ func (pm *ProtocolManager) BroadcastTransactions(txs types.Transactions, propaga
 			peers := pm.peers.PeersWithoutTx(tx.Hash())
 
 			// Send the block to a subset of our peers
-			transferLen := int(math.Sqrt(float64(len(peers))))
-			if transferLen < minBroadcastPeers {
-				transferLen = minBroadcastPeers
-			}
-			if transferLen > len(peers) {
-				transferLen = len(peers)
-			}
-			transfer := peers[:transferLen]
+			transfer := peers[:int(math.Sqrt(float64(len(peers))))]
 			for _, peer := range transfer {
 				txset[peer] = append(txset[peer], tx.Hash())
 			}

eth/handler_test.go

@@ -554,12 +554,12 @@ func TestBroadcastBlock(t *testing.T) {
 		broadcastExpected int
 	}{
 		{1, 1},
-		{2, 2},
-		{3, 3},
-		{4, 4},
-		{5, 4},
-		{9, 4},
-		{12, 4},
+		{2, 1},
+		{3, 1},
+		{4, 2},
+		{5, 2},
+		{9, 3},
+		{12, 3},
 		{16, 4},
 		{26, 5},
 		{100, 10},
@@ -592,6 +592,7 @@ func testBroadcastBlock(t *testing.T, totalPeers, broadcastExpected int) {
 	for i := 0; i < totalPeers; i++ {
 		peer, _ := newTestPeer(fmt.Sprintf("peer %d", i), eth63, pm, true)
 		defer peer.close()
+
 		peers = append(peers, peer)
 	}
 	chain, _ := core.GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 1, func(i int, gen *core.BlockGen) {})
@@ -608,31 +609,23 @@ func testBroadcastBlock(t *testing.T, totalPeers, broadcastExpected int) {
 			}
 		}(peer)
 	}
-	timeout := time.After(2 * time.Second)
-	var receivedCount int
-outer:
+	var received int
 	for {
 		select {
-		case err = <-errCh:
-			break outer
 		case <-doneCh:
-			receivedCount++
-			if receivedCount == totalPeers {
-				break outer
+			received++
+
+		case <-time.After(100 * time.Millisecond):
+			if received != broadcastExpected {
+				t.Errorf("broadcast count mismatch: have %d, want %d", received, broadcastExpected)
 			}
-		case <-timeout:
-			break outer
+			return
+
+		case err = <-errCh:
+			t.Fatalf("broadcast failed: %v", err)
 		}
 	}
-	for _, peer := range peers {
-		peer.app.Close()
-	}
-	if err != nil {
-		t.Errorf("error matching block by peer: %v", err)
-	}
-	if receivedCount != broadcastExpected {
-		t.Errorf("block broadcast to %d peers, expected %d", receivedCount, broadcastExpected)
-	}
+
 }
 
 // Tests that a propagated malformed block (uncles or transactions don't match