Add benches for shredding and poh (#6307)

* Add benches for shredding and poh

* ignore poh bench

* Factor out Poh bench as separate function

core/benches/shredder.rs

@@ -3,17 +3,33 @@
 extern crate test;
 
 use solana_core::entry::create_ticks;
+use solana_core::entry::Entry;
 use solana_core::shred::{
-    max_ticks_per_n_shreds, Shredder, RECOMMENDED_FEC_RATE, SIZE_OF_DATA_SHRED_HEADER,
+    max_entries_per_n_shred, max_ticks_per_n_shreds, Shredder, RECOMMENDED_FEC_RATE,
+    SIZE_OF_DATA_SHRED_HEADER,
 };
+use solana_core::test_tx;
 use solana_sdk::hash::Hash;
 use solana_sdk::packet::PACKET_DATA_SIZE;
 use solana_sdk::signature::{Keypair, KeypairUtil};
 use std::sync::Arc;
 use test::Bencher;
 
+fn make_test_entry(txs_per_entry: u64) -> Entry {
+    Entry {
+        num_hashes: 100_000,
+        hash: Hash::default(),
+        transactions: vec![test_tx::test_tx(); txs_per_entry as usize],
+    }
+}
+fn make_large_unchained_entries(txs_per_entry: u64, num_entries: u64) -> Vec<Entry> {
+    (0..num_entries)
+        .map(|_| make_test_entry(txs_per_entry))
+        .collect()
+}
+
 #[bench]
-fn bench_shredder(bencher: &mut Bencher) {
+fn bench_shredder_ticks(bencher: &mut Bencher) {
     let kp = Arc::new(Keypair::new());
     let shred_size = PACKET_DATA_SIZE - *SIZE_OF_DATA_SHRED_HEADER;
     let num_shreds = ((1000 * 1000) + (shred_size - 1)) / shred_size;
@@ -26,6 +42,21 @@ fn bench_shredder(bencher: &mut Bencher) {
     })
 }
 
+#[bench]
+fn bench_shredder_large_entries(bencher: &mut Bencher) {
+    let kp = Arc::new(Keypair::new());
+    let shred_size = PACKET_DATA_SIZE - *SIZE_OF_DATA_SHRED_HEADER;
+    let num_shreds = ((1000 * 1000) + (shred_size - 1)) / shred_size;
+    let txs_per_entry = 128;
+    let num_entries = max_entries_per_n_shred(&make_test_entry(txs_per_entry), num_shreds as u64);
+    let entries = make_large_unchained_entries(txs_per_entry, num_entries);
+    // 1Mb
+    bencher.iter(|| {
+        let shredder = Shredder::new(1, 0, RECOMMENDED_FEC_RATE, kp.clone()).unwrap();
+        shredder.entries_to_shreds(&entries, true, 0);
+    })
+}
+
 #[bench]
 fn bench_deshredder(bencher: &mut Bencher) {
     let kp = Arc::new(Keypair::new());