v1.16: Increase push fanout from 6 to 9 (backport of #32323) (#32335)

Increase push fanout from 6 to 9 (#32323)

* increase push fanout from 6 to 9. leave active set size at 12

* forgot to change comment to reflect push fanout increase

(cherry picked from commit b8222b2)

Co-authored-by: Greg Cusack <greg.cusack@solana.com>

gossip/src/crds_gossip_push.rs

@@ -42,15 +42,15 @@ use {
     },
 };
 
-const CRDS_GOSSIP_PUSH_FANOUT: usize = 6;
-// With a fanout of 6, a 1000 node cluster should only take ~4 hops to converge.
+const CRDS_GOSSIP_PUSH_FANOUT: usize = 9;
+// With a fanout of 9, a 2000 node cluster should only take ~3.5 hops to converge.
 // However since pushes are stake weighed, some trailing nodes
 // might need more time to receive values. 30 seconds should be plenty.
 pub const CRDS_GOSSIP_PUSH_MSG_TIMEOUT_MS: u64 = 30000;
 const CRDS_GOSSIP_PRUNE_MSG_TIMEOUT_MS: u64 = 500;
 const CRDS_GOSSIP_PRUNE_STAKE_THRESHOLD_PCT: f64 = 0.15;
 const CRDS_GOSSIP_PRUNE_MIN_INGRESS_NODES: usize = 2;
-const CRDS_GOSSIP_PUSH_ACTIVE_SET_SIZE: usize = CRDS_GOSSIP_PUSH_FANOUT * 2;
+const CRDS_GOSSIP_PUSH_ACTIVE_SET_SIZE: usize = CRDS_GOSSIP_PUSH_FANOUT + 3;
 
 pub struct CrdsGossipPush {
     /// Max bytes per message