From runtime profiles, the majority time of ClusterInfo::handle_purge
https://github.com/solana-labs/solana/blob/0776fa05c/core/src/cluster_info.rs#L1605-L1626
is spent scanning crds table finding old labels:
https://github.com/solana-labs/solana/blob/0776fa05c/core/src/crds.rs#L175-L197
This can be done in parallel given that gossip thread-pool:
https://github.com/solana-labs/solana/blob/0776fa05c/core/src/cluster_info.rs#L1637-L1641
is idle when handle_purge is invoked:
https://github.com/solana-labs/solana/blob/0776fa05c/core/src/cluster_info.rs#L1681
(cherry picked from commit 37c8842bcb
)
Co-authored-by: behzad nouri <behzadnouri@gmail.com>