Add validator option to change niceness of snapshot packager thread

Cargo.lock

@@ -4558,6 +4558,7 @@ dependencies = [
  "chrono",
  "clap 2.33.3",
  "rpassword",
+ "solana-perf",
  "solana-remote-wallet",
  "solana-sdk",
  "tempfile",

clap-utils/Cargo.toml

@@ -12,6 +12,7 @@ edition = "2018"
 [dependencies]
 clap = "2.33.0"
 rpassword = "5.0"
+solana-perf = { path = "../perf", version = "=1.9.0" }
 solana-remote-wallet = { path = "../remote-wallet", version = "=1.9.0" }
 solana-sdk = { path = "../sdk", version = "=1.9.0" }
 thiserror = "1.0.30"

clap-utils/src/input_validators.rs

@@ -370,6 +370,27 @@ where
     }
 }
 
+pub fn is_niceness_adjustment_valid<T>(value: T) -> Result<(), String>
+where
+    T: AsRef<str> + Display,
+{
+    let adjustment = value.as_ref().parse::<i8>().map_err(|err| {
+        format!(
+            "error parsing niceness adjustment value '{}': {}",
+            value, err
+        )
+    })?;
+    if solana_perf::thread::is_renice_allowed(adjustment) {
+        Ok(())
+    } else {
+        Err(String::from(
+            "niceness adjustment supported only on Linux; negative adjustment \
+             (priority increase) requires root or CAP_SYS_NICE (see `man 7 capabilities` \
+             for details)",
+        ))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -386,4 +407,11 @@ mod tests {
         assert!(is_derivation("a/b").is_err());
         assert!(is_derivation("0/4294967296").is_err());
     }
+
+    #[test]
+    fn test_is_niceness_adjustment_valid() {
+        assert_eq!(is_niceness_adjustment_valid("0"), Ok(()));
+        assert!(is_niceness_adjustment_valid("128").is_err());
+        assert!(is_niceness_adjustment_valid("-129").is_err());
+    }
 }

core/src/snapshot_packager_service.rs

@@ -1,6 +1,7 @@
 use solana_gossip::cluster_info::{
     ClusterInfo, MAX_INCREMENTAL_SNAPSHOT_HASHES, MAX_SNAPSHOT_HASHES,
 };
+use solana_perf::thread::renice_this_thread;
 use solana_runtime::{
     snapshot_archive_info::SnapshotArchiveInfoGetter,
     snapshot_config::SnapshotConfig,
@@ -48,6 +49,7 @@ impl SnapshotPackagerService {
         let t_snapshot_packager = Builder::new()
             .name("snapshot-packager".to_string())
             .spawn(move || {
+                renice_this_thread(snapshot_config.packager_thread_niceness_adj).unwrap();
                 let mut snapshot_gossip_manager = if enable_gossip_push {
                     Some(SnapshotGossipManager {
                         cluster_info,

runtime/src/snapshot_config.rs

@@ -35,6 +35,9 @@ pub struct SnapshotConfig {
 
     /// This is the `debug_verify` parameter to use when calling `update_accounts_hash()`
     pub accounts_hash_debug_verify: bool,
+
+    // Thread niceness adjustment for snapshot packager service
+    pub packager_thread_niceness_adj: i8,
 }
 
 impl Default for SnapshotConfig {
@@ -54,6 +57,7 @@ impl Default for SnapshotConfig {
                 snapshot_utils::DEFAULT_MAX_INCREMENTAL_SNAPSHOT_ARCHIVES_TO_RETAIN,
             accounts_hash_use_index: false,
             accounts_hash_debug_verify: false,
+            packager_thread_niceness_adj: 0,
         }
     }
 }

validator/src/main.rs

@@ -10,8 +10,8 @@ use {
     solana_clap_utils::{
         input_parsers::{keypair_of, keypairs_of, pubkey_of, value_of},
         input_validators::{
-            is_keypair, is_keypair_or_ask_keyword, is_parsable, is_pow2, is_pubkey,
+            is_keypair, is_keypair_or_ask_keyword, is_niceness_adjustment_valid, is_parsable,
-            is_pubkey_or_keypair, is_slot, is_valid_percentage,
+            is_pow2, is_pubkey, is_pubkey_or_keypair, is_slot, is_valid_percentage,
         },
         keypair::SKIP_SEED_PHRASE_VALIDATION_ARG,
     },
@@ -910,6 +910,16 @@ pub fn main() {
                 .default_value(default_maximum_incremental_snapshot_archives_to_retain)
                 .help("The maximum number of incremental snapshot archives to hold on to when purging older snapshots.")
         )
+        .arg(
+            Arg::with_name("snapshot_packager_niceness_adj")
+                .long("snapshot-packager-niceness-adjustment")
+                .value_name("ADJUSTMENT")
+                .takes_value(true)
+                .validator(is_niceness_adjustment_valid)
+                .default_value("0")
+                .help("Add this value to niceness of snapshot packager thread. Negative value \
+                      increases priority, positive value decreases priority.")
+        )
         .arg(
             Arg::with_name("minimal_snapshot_download_speed")
                 .long("minimal-snapshot-download-speed")
@@ -2328,6 +2338,8 @@ pub fn main() {
         value_t_or_exit!(matches, "maximum_full_snapshots_to_retain", usize);
     let maximum_incremental_snapshot_archives_to_retain =
         value_t_or_exit!(matches, "maximum_incremental_snapshots_to_retain", usize);
+    let snapshot_packager_niceness_adj =
+        value_t_or_exit!(matches, "snapshot_packager_niceness_adj", i8);
     let minimal_snapshot_download_speed =
         value_t_or_exit!(matches, "minimal_snapshot_download_speed", f32);
     let maximum_snapshot_download_abort =
@@ -2395,6 +2407,7 @@ pub fn main() {
         maximum_incremental_snapshot_archives_to_retain,
         accounts_hash_use_index: validator_config.accounts_db_use_index_hash_calculation,
         accounts_hash_debug_verify: validator_config.accounts_db_test_hash_calculation,
+        packager_thread_niceness_adj: snapshot_packager_niceness_adj,
     });
 
     validator_config.accounts_hash_interval_slots =