add a parallel construction benchmark to src/main.rs

src/main.rs

@@ -3,7 +3,7 @@ use std::time::Instant;
 use clap::Parser;
 use miden_crypto::{
     hash::rpo::{Rpo256, RpoDigest},
-    merkle::{MerkleError, Smt},
+    merkle::{MerkleError, NodeIndex, Smt},
     Felt, Word, ONE,
 };
 use rand_utils::rand_value;
@@ -33,7 +33,9 @@ pub fn benchmark_smt() {
         entries.push((key, value));
     }
 
-    let mut tree = construction(entries, tree_size).unwrap();
+    let mut tree = construction(entries.clone(), tree_size).unwrap();
+    let parallel = parallel_construction(entries, tree_size).unwrap();
+    assert_eq!(tree, parallel);
     insertion(&mut tree, tree_size).unwrap();
     batched_insertion(&mut tree, tree_size).unwrap();
     proof_generation(&mut tree, tree_size).unwrap();
@@ -56,6 +58,31 @@ pub fn construction(entries: Vec<(RpoDigest, Word)>, size: u64) -> Result<Smt, M
     Ok(tree)
 }
 
+pub fn parallel_construction(
+    entries: Vec<(RpoDigest, Word)>,
+    size: u64,
+) -> Result<Smt, MerkleError> {
+    println!("Running a parallel construction benchmark:");
+    let now = Instant::now();
+
+    let (inner_nodes, leaves) = Smt::build_subtrees(entries);
+    let root = inner_nodes.get(&NodeIndex::root()).unwrap().hash();
+
+    let leaves = leaves.into_iter().map(|(key, value)| (key.value(), value)).collect();
+
+    let tree = Smt::from_raw_parts(inner_nodes, leaves, root)?;
+
+    let elapsed = now.elapsed();
+    println!(
+        "Parallel-constructed an SMT with {} key-value pairs in {:.3} seconds",
+        size,
+        elapsed.as_secs_f32(),
+    );
+    println!("Number of leaf nodes: {}\n", tree.leaves().count());
+
+    Ok(tree)
+}
+
 /// Runs the insertion benchmark for the [`Smt`].
 pub fn insertion(tree: &mut Smt, size: u64) -> Result<(), MerkleError> {
     println!("Running an insertion benchmark:");