Add --rpc-threads argument

core/Cargo.toml

@@ -38,7 +38,6 @@ log = "0.4.11"
 lru = "0.6.1"
 miow = "0.2.2"
 net2 = "0.2.37"
-num_cpus = "1.13.0"
 num-traits = "0.2"
 rand = "0.7.0"
 rand_chacha = "0.2.2"
@@ -88,6 +87,7 @@ trees = "0.2.1"
 
 [dev-dependencies]
 matches = "0.1.6"
+num_cpus = "1.13.0"
 reqwest = { version = "0.10.8", default-features = false, features = ["blocking", "rustls-tls", "json"] }
 serial_test = "0.4.0"
 serial_test_derive = "0.4.0"

core/src/rpc.rs

@@ -112,6 +112,7 @@ pub struct JsonRpcConfig {
     pub enable_bigtable_ledger_upload: bool,
     pub max_multiple_accounts: Option<usize>,
     pub account_indexes: HashSet<AccountIndex>,
+    pub rpc_threads: usize,
 }
 
 #[derive(Clone)]

core/src/rpc_service.rs

@@ -273,6 +273,7 @@ impl JsonRpcService {
     ) -> Self {
         info!("rpc bound to {:?}", rpc_addr);
         info!("rpc configuration: {:?}", config);
+        let rpc_threads = 1.max(config.rpc_threads);
 
         let health = Arc::new(RpcHealth::new(
             cluster_info.clone(),
@@ -374,7 +375,7 @@ impl JsonRpcService {
                     io,
                     move |_req: &hyper::Request<hyper::Body>| request_processor.clone(),
                 )
-                .threads(num_cpus::get())
+                .threads(rpc_threads)
                 .cors(DomainsValidation::AllowOnly(vec![
                     AccessControlAllowOrigin::Any,
                 ]))