speed up merkle calculation (#14710)

merkle-root-bench/src/main.rs

@@ -0,0 +1,65 @@
+extern crate log;
+use clap::{crate_description, crate_name, value_t, App, Arg};
+use solana_measure::measure::Measure;
+use solana_runtime::accounts_db::AccountsDB;
+use solana_sdk::{hash::Hash, pubkey::Pubkey};
+
+fn main() {
+    solana_logger::setup();
+
+    let matches = App::new(crate_name!())
+        .about(crate_description!())
+        .version(solana_version::version!())
+        .arg(
+            Arg::with_name("num_accounts")
+                .long("num_accounts")
+                .takes_value(true)
+                .value_name("NUM_ACCOUNTS")
+                .help("Total number of accounts"),
+        )
+        .arg(
+            Arg::with_name("iterations")
+                .long("iterations")
+                .takes_value(true)
+                .value_name("ITERATIONS")
+                .help("Number of bench iterations"),
+        )
+        .get_matches();
+
+    let num_accounts = value_t!(matches, "num_accounts", usize).unwrap_or(10_000);
+    let iterations = value_t!(matches, "iterations", usize).unwrap_or(20);
+    let mut elapsed: Vec<u64> = vec![0; iterations];
+    let mut elapsed_legacy: Vec<u64> = vec![0; iterations];
+    let hashes: Vec<_> = (0..num_accounts)
+        .map(|_| (Pubkey::new_unique(), Hash::new_unique(), 1))
+        .collect();
+    for x in 0..iterations {
+        let hashes = (hashes.clone(), hashes.clone()); // done outside timing
+        let mut time = Measure::start("compute_merkle_root_and_capitalization");
+        let fanout = 16;
+        let results = AccountsDB::compute_merkle_root_and_capitalization(hashes.0, fanout);
+        time.stop();
+        let mut time_legacy = Measure::start("hash");
+        let results_hash = AccountsDB::compute_merkle_root_legacy(hashes.1, fanout);
+        time_legacy.stop();
+        assert_eq!(results_hash, results.0);
+        elapsed[x] = time.as_us();
+        elapsed_legacy[x] = time_legacy.as_us();
+    }
+
+    let len = elapsed.len();
+    for x in 0..iterations {
+        println!(
+            "compute_merkle_root_and_capitalization(us),{},legacy(us),{}",
+            elapsed[x], elapsed_legacy[x]
+        );
+    }
+    println!(
+        "compute_merkle_root_and_capitalization(us) avg: {}",
+        elapsed.into_iter().sum::<u64>() as f64 / len as f64
+    );
+    println!(
+        "compute_merkle_root_legacy(us) avg: {}",
+        elapsed_legacy.into_iter().sum::<u64>() as f64 / len as f64
+    );
+}