quic: use smallvec to aggregate chunks, save 1 alloc per packet (#735)

quic: use smallvec, save one allocation per packet

Use smallvec to hold chunks. Streams are packet-sized so we don't expect
them to have many chunks. This saves us an allocation for each packet.

(cherry picked from commit 55ab7fa)

# Conflicts:
#	programs/sbf/Cargo.lock
#	streamer/Cargo.toml
#	streamer/src/nonblocking/quic.rs

Cargo.toml

@@ -303,7 +303,7 @@ sha2 = "0.10.8"
 sha3 = "0.10.4"
 signal-hook = "0.3.17"
 siphasher = "0.3.11"
-smallvec = "1.13.1"
+smallvec = "1.13.2"
 smpl_jwt = "0.7.1"
 socket2 = "0.5.5"
 soketto = "0.7"

streamer/Cargo.toml

@@ -28,6 +28,11 @@ quinn-proto = { workspace = true }
 rand = { workspace = true }
 rcgen = { workspace = true }
 rustls = { workspace = true, features = ["dangerous_configuration"] }
+<<<<<<< HEAD
+=======
+smallvec = { workspace = true }
+solana-measure = { workspace = true }
+>>>>>>> 55ab7fadbc (quic: use smallvec to aggregate chunks, save 1 alloc per packet (#735))
 solana-metrics = { workspace = true }
 solana-perf = { workspace = true }
 solana-sdk = { workspace = true }

streamer/src/nonblocking/quic.rs

@@ -17,6 +17,11 @@ use {
     quinn::{Connecting, Connection, Endpoint, EndpointConfig, TokioRuntime, VarInt},
     quinn_proto::VarIntBoundsExceeded,
     rand::{thread_rng, Rng},
+<<<<<<< HEAD
+=======
+    smallvec::SmallVec,
+    solana_measure::measure::Measure,
+>>>>>>> 55ab7fadbc (quic: use smallvec to aggregate chunks, save 1 alloc per packet (#735))
     solana_perf::packet::{PacketBatch, PACKETS_PER_BATCH},
     solana_sdk::{
         packet::{Meta, PACKET_DATA_SIZE},
@@ -93,7 +98,12 @@ struct PacketChunk {
 // the Packet and then when copying the Packet into a PacketBatch)
 struct PacketAccumulator {
     pub meta: Meta,
+<<<<<<< HEAD
     pub chunks: Vec<PacketChunk>,
+=======
+    pub chunks: SmallVec<[PacketChunk; 2]>,
+    pub start_time: Instant,
+>>>>>>> 55ab7fadbc (quic: use smallvec to aggregate chunks, save 1 alloc per packet (#735))
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -872,7 +882,12 @@ async fn handle_chunk(
                     meta.set_socket_addr(remote_addr);
                     *packet_accum = Some(PacketAccumulator {
                         meta,
+<<<<<<< HEAD
                         chunks: Vec::new(),
+=======
+                        chunks: SmallVec::new(),
+                        start_time: Instant::now(),
+>>>>>>> 55ab7fadbc (quic: use smallvec to aggregate chunks, save 1 alloc per packet (#735))
                     });
                 }
 
@@ -1471,7 +1486,7 @@ pub mod test {
             meta.size = size;
             let packet_accum = PacketAccumulator {
                 meta,
-                chunks: vec![PacketChunk {
+                chunks: smallvec::smallvec![PacketChunk {
                     bytes,
                     offset,
                     end_of_chunk: size,