Use VecDeque instead of Vec in sigverify stage (backport #22538)

core/benches/sigverify_stage.rs

@@ -1,4 +1,5 @@
 #![feature(test)]
+#![allow(clippy::integer_arithmetic)]
 
 extern crate solana_core;
 extern crate test;
@@ -22,8 +23,7 @@ use {
     test::Bencher,
 };
 
-#[bench]
-fn bench_packet_discard(bencher: &mut Bencher) {
+fn run_bench_packet_discard(num_ips: usize, bencher: &mut Bencher) {
     solana_logger::setup();
     let len = 30 * 1000;
     let chunk_size = 1024;
@@ -32,7 +32,7 @@ fn bench_packet_discard(bencher: &mut Bencher) {
 
     let mut total = 0;
 
-    let ips: Vec<_> = (0..10_000)
+    let ips: Vec<_> = (0..num_ips)
         .into_iter()
         .map(|_| {
             let mut addr = [0u16; 8];
@@ -60,6 +60,16 @@ fn bench_packet_discard(bencher: &mut Bencher) {
     });
 }
 
+#[bench]
+fn bench_packet_discard_many_senders(bencher: &mut Bencher) {
+    run_bench_packet_discard(1000, bencher);
+}
+
+#[bench]
+fn bench_packet_discard_single_sender(bencher: &mut Bencher) {
+    run_bench_packet_discard(1, bencher);
+}
+
 #[bench]
 fn bench_sigverify_stage(bencher: &mut Bencher) {
     solana_logger::setup();

core/src/sigverify_stage.rs

@@ -13,7 +13,7 @@ use {
     solana_sdk::timing,
     solana_streamer::streamer::{self, PacketBatchReceiver, StreamerError},
     std::{
-        collections::HashMap,
+        collections::{HashMap, VecDeque},
         sync::mpsc::{Receiver, RecvTimeoutError},
         thread::{self, Builder, JoinHandle},
         time::Instant,
@@ -145,17 +145,17 @@ impl SigVerifyStage {
             for (packet_index, packets) in batch.packets.iter().enumerate() {
                 let e = received_ips
                     .entry(packets.meta.addr().ip())
-                    .or_insert_with(Vec::new);
-                e.push((batch_index, packet_index));
+                    .or_insert_with(VecDeque::new);
+                e.push_back((batch_index, packet_index));
             }
         }
         let mut batch_len = 0;
         while batch_len < max_packets {
             for (_ip, indexes) in received_ips.iter_mut() {
                 if !indexes.is_empty() {
-                    indexes.remove(0);
+                    indexes.pop_front();
                     batch_len += 1;
-                    if batch_len >= MAX_SIGVERIFY_BATCH {
+                    if batch_len >= max_packets {
                         break;
                     }
                 }