mark_pull_request_creation time requires an exclusive lock on gossip: https://github.com/solana-labs/solana/blob/16944e218/core/src/cluster_info.rs#L1547-L1548 Current code is redundantly marking each peer once for each request. There are at most only 2 unique peers, whereas there are hundreds of requests per each. So the lock is acquired hundreds of time longer than necessary.