final tweaks to the peer selection and pruning algo

lambdaclass · Oct 2, 2024 · 850f50f · 850f50f
1 parent 8dd5522
commit 850f50f
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Showing 3 changed files with 15 additions and 19 deletions.
diff --git a/lib/lambda_ethereum_consensus/p2p/blob_downloader.ex b/lib/lambda_ethereum_consensus/p2p/blob_downloader.ex
@@ -61,8 +61,7 @@ defmodule LambdaEthereumConsensus.P2P.BlobDownloader do
         P2P.Peerbook.penalize_peer(peer_id)
 
         if retries > 0 do
-          Logger.info("Retrying request for #{count} blobs: #{inspect(reason)}", slot: slot)
-
+          Logger.debug("Retrying request for #{count} blobs: #{inspect(reason)}", slot: slot)
           request_blobs_by_range(slot, count, on_blobs, retries - 1)
           {:ok, store}
         else

diff --git a/lib/lambda_ethereum_consensus/p2p/block_downloader.ex b/lib/lambda_ethereum_consensus/p2p/block_downloader.ex
@@ -173,10 +173,7 @@ defmodule LambdaEthereumConsensus.P2P.BlockDownloader do
           :telemetry.execute([:network, :request], %{blocks: 0}, Map.put(tags, :result, "retry"))
           pretty_roots = Enum.map_join(roots, ", ", &Base.encode16/1)
 
-          Logger.info(
-            "Retrying request for blocks with roots #{pretty_roots}: #{inspect(reason)}"
-          )
-
+          Logger.debug("Retrying request for block roots #{pretty_roots}: #{inspect(reason)}")
           request_blocks_by_root(roots, on_blocks, retries - 1)
           {:ok, store}
         else

diff --git a/lib/lambda_ethereum_consensus/p2p/peerbook.ex b/lib/lambda_ethereum_consensus/p2p/peerbook.ex
@@ -8,7 +8,7 @@ defmodule LambdaEthereumConsensus.P2P.Peerbook do
   alias LambdaEthereumConsensus.Utils
 
   @initial_score 100
-  @penalize 35
+  @penalizing_score 25
   @target_peers 128
   @max_prune_size 8
   @prune_percentage 0.05
@@ -44,15 +44,16 @@ defmodule LambdaEthereumConsensus.P2P.Peerbook do
   Get some peer from the peerbook.
   """
   def get_some_peer() do
-    # TODO: This is a very naive implementation of a peer selection algorithm.
+    # TODO: This is a very naive implementation of a peer selection algorithm,
+    # this sorts the peers every time.
     peerbook = fetch_peerbook!()
 
     if peerbook == %{} do
       nil
     else
       peerbook
-      |> Enum.sort_by(fn {_peer_id, score} -> score end)
-      |> Enum.take(4)
+      |> Enum.sort_by(fn {_peer_id, score} -> -score end)
+      |> Enum.take(5)
       |> Enum.random()
       |> elem(0)
     end
@@ -67,7 +68,7 @@ defmodule LambdaEthereumConsensus.P2P.Peerbook do
       nil ->
         :ok
 
-      score when score - @penalize <= 0 ->
+      score when score - @penalizing_score <= 0 ->
         Logger.debug("[Peerbook] Removing peer: #{inspect(Utils.format_shorten_binary(peer_id))}")
 
         fetch_peerbook!()
@@ -76,7 +77,7 @@ defmodule LambdaEthereumConsensus.P2P.Peerbook do
 
       score ->
         fetch_peerbook!()
-        |> Map.put(peer_id, score - @penalize)
+        |> Map.put(peer_id, score - @penalizing_score)
         |> store_peerbook()
     end
   end
@@ -119,13 +120,12 @@ defmodule LambdaEthereumConsensus.P2P.Peerbook do
         |> min(len - @target_peers)
         |> max(0)
 
-      n = :rand.uniform(len)
-
-      peerbook
-      |> Map.keys()
-      |> Stream.drop(n)
-      |> Stream.take(prune_size)
-      |> Enum.each(fn peer_id -> Task.start(__MODULE__, :challenge_peer, [peer_id]) end)
+      if prune_size > 0 do
+        peerbook
+        |> Enum.sort_by(fn {_peer_id, score} -> -score end)
+        |> Enum.take(prune_size)
+        |> Enum.each(fn peer_id -> Task.start(__MODULE__, :challenge_peer, [peer_id]) end)
+      end
     end
   end