Add --rpc-threads argument (#14568)

(cherry picked from commit 11daaadc93)

Co-authored-by: Michael Vines <mvines@gmail.com>

validator/Cargo.toml

@@ -19,6 +19,7 @@ core_affinity = "0.5.10"
 fd-lock = "1.1.1"
 indicatif = "0.15.0"
 log = "0.4.11"
+num_cpus = "1.13.0"
 rand = "0.7.0"
 serde_json = "1.0.56"
 solana-clap-utils = { path = "../clap-utils", version = "1.5.3" }

validator/src/main.rs

@@ -826,6 +826,7 @@ pub fn main() {
     let default_rpc_send_transaction_leader_forward_count = ValidatorConfig::default()
         .send_transaction_leader_forward_count
         .to_string();
+    let default_rpc_threads = num_cpus::get().to_string();
 
     let matches = App::new(crate_name!()).about(crate_description!())
         .version(solana_version::version!())
@@ -1277,6 +1278,15 @@ pub fn main() {
                 .validator(solana_net_utils::is_host)
                 .help("IP address to bind the RPC port [default: use --bind-address]"),
         )
+        .arg(
+            Arg::with_name("rpc_threads")
+                .long("rpc-threads")
+                .value_name("NUMBER")
+                .validator(is_parsable::<usize>)
+                .takes_value(true)
+                .default_value(&default_rpc_threads)
+                .help("Number of threads to use for servicing RPC requests"),
+        )
         .arg(
             Arg::with_name("rpc_pubsub_enable_vote_subscription")
                 .long("rpc-pubsub-enable-vote-subscription")
@@ -1550,6 +1560,7 @@ pub fn main() {
                 "health_check_slot_distance",
                 u64
             ),
+            rpc_threads: value_t_or_exit!(matches, "rpc_threads", usize),
             account_indexes: account_indexes.clone(),
         },
         rpc_addrs: value_t!(matches, "rpc_port", u16).ok().map(|rpc_port| {