feat(eth-sparse-mpt): add ~3x faster v3 state-root implementation and harness tools (#887)

## 📝 Summary

I will state upfront that this code is almost entirely written with
Codex. However, the results seem promising and it shares much overlap
with the existing v2 state root anyway.

I asked Codex to setup a harness that measured performance across
different depths of cache warmth and compared state root implementations
to each other and Reth's for correctness. Then I asked it to optimize v2
and implement a v3 state root. This was effective because the agent
could simply iterate if it noticed it had the wrong root or if it was
slower. Finally, I ran the harness for 1000+ blocks and the new v3
always produced the same root as v2 and reth, so I have some confidence
in the implementation. You can find the testing scripts in this PR,
specifically `correct_and_bench.rs`. Note that these require unwinding a
reth node block by block (thank you Vitaly for this trick).

The results are a significant speedup relative to v2. Over 1,000 blocks:

| Scope | v2 p50 | v3 p50 | v2 p99 | v3 p99 | v2 mean | v3 mean |
  |---|---:|---:|---:|---:|---:|---:|
| Overall (excluding warm=100, n=3213) | 3.01 | 0.88 | 4.71 | 1.87 |
3.19 | 0.97 |

| Warm % | v2 p50 | v3 p50 | p50 speedup | v2 p99 | v3 p99 | p99 speedup
| v2 mean | v3 mean | mean speedup |
  |---|---:|---:|---:|---:|---:|---:|---:|---:|---:|
| 70 | 4.16 | 1.09 | 3.82x | 5.96 | 2.22 | 2.68x | 4.32 | 1.21 | 3.58x |
| 80 | 3.05 | 0.94 | 3.26x | 4.75 | 1.93 | 2.46x | 3.23 | 1.03 | 3.14x |
| 90 | 1.83 | 0.61 | 3.00x | 3.41 | 1.45 | 2.35x | 2.00 | 0.68 | 2.95x |

Here's a moving average:
<img width="2160" height="1620" alt="image"
src="https://github.com/user-attachments/assets/2e8778d0-63c3-4d72-bb17-f0a442c7af6b"
/>


The one notable regression is that in ~2.5% of blocks there were v3 p99
cases that were greater than v2. On average these regressions added
1.89ms, and the worst observed was 23.9ms for a single block.


## 💡 Motivation and Context
Calculating the state root is in the hot path for a new block so making
it faster lowers latency for all our users.

---

## ✅ I have completed the following steps:

* [x] Run `make lint`
* [x] Run `make test`
* [x] Added tests (if applicable)

---------

Co-authored-by: Vitalii Drohan <vitaliy.drogan@gmail.com>

Author: bertmiller

Cargo.lock

@@ -90,6 +90,7 @@ reth-provider = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6
 reth-chainspec = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
 reth-evm = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
 reth-evm-ethereum = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
+reth-revm = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
 reth-execution-errors = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
 reth-trie-db = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }
 reth-transaction-pool = { git = "https://github.com/paradigmxyz/reth", rev = "27a8c0f5a6dfb27dea84c5751776ecabdd069646" }

Cargo.toml

@@ -22,11 +22,19 @@ nybbles = { version = "0.3.3", features = ["serde"] }
 tracing.workspace = true
 
 # reth
+reth-chainspec = { workspace = true, optional = true }
+reth-db = { workspace = true, optional = true }
+reth-evm = { workspace = true, optional = true }
+reth-evm-ethereum = { workspace = true, optional = true }
 reth-errors.workspace = true
 reth-execution-errors.workspace = true
+reth-node-api = { workspace = true, optional = true }
+reth-node-ethereum = { workspace = true, optional = true }
 reth-trie.workspace = true
+reth-trie-parallel = { workspace = true, optional = true }
 reth-trie-db.workspace = true
 reth-provider.workspace = true
+reth-revm = { workspace = true, optional = true }
 
 # revm
 revm.workspace = true
@@ -48,6 +56,16 @@ flate2 = { workspace = true, optional = true }
 
 [features]
 benchmark-utils = ["dep:hash-db", "dep:triehash", "dep:flate2"]
+dev-tools = [
+    "dep:reth-chainspec",
+    "dep:reth-db",
+    "dep:reth-evm",
+    "dep:reth-evm-ethereum",
+    "dep:reth-node-api",
+    "dep:reth-node-ethereum",
+    "dep:reth-trie-parallel",
+    "dep:reth-revm",
+]
 
 [dev-dependencies]
 criterion = { workspace = true, features = ["html_reports"] }
@@ -71,3 +89,21 @@ harness = false
 name = "trie_do_bench"
 harness = false
 
+[[bench]]
+name = "trie_bench_v2_v_experimental"
+harness = false
+
+[[bin]]
+name = "correctness-harness"
+path = "src/bin/correctness-harness.rs"
+required-features = ["dev-tools"]
+
+[[bin]]
+name = "cache-warm-compare"
+path = "src/bin/cache-warm-compare.rs"
+required-features = ["dev-tools"]
+
+[[bin]]
+name = "correct_and_bench"
+path = "src/bin/correct_and_bench.rs"
+required-features = ["dev-tools"]

crates/eth-sparse-mpt/Cargo.toml

@@ -0,0 +1,60 @@
+use alloy_primitives::{keccak256, Bytes, B256, U256};
+use criterion::{criterion_group, criterion_main, Criterion};
+use eth_sparse_mpt::{
+    v2::trie::{proof_store::ProofStore as ProofStoreV2, Trie as TrieV2},
+    v_experimental::trie::{
+        proof_store::ProofStore as ProofStoreVExperimental, Trie as TrieVExperimental,
+    },
+};
+
+fn prepare_key_value_data(n: usize) -> (Vec<Bytes>, Vec<Bytes>) {
+    let mut keys = Vec::with_capacity(n);
+    let mut values = Vec::with_capacity(n);
+    for i in 0u64..(n as u64) {
+        let b: B256 = U256::from(i).into();
+        let data = keccak256(b).to_vec();
+        let value = keccak256(&data).to_vec();
+        keys.push(Bytes::copy_from_slice(data.as_slice()));
+        values.push(Bytes::copy_from_slice(value.as_slice()));
+    }
+    (keys, values)
+}
+
+fn insert_nodes_v2_v_experimental(c: &mut Criterion) {
+    let (keys, values) = prepare_key_value_data(10000);
+
+    let empty_proof_store_v2 = ProofStoreV2::default();
+    let mut v2_hash = B256::ZERO;
+    let mut trie_v2 = TrieV2::new_empty();
+    c.bench_function("insert_nodes_v2", |b| {
+        b.iter(|| {
+            trie_v2.clear_empty();
+            for (key, value) in keys.iter().zip(values.iter()) {
+                trie_v2.insert(key, value).unwrap();
+            }
+            v2_hash = trie_v2.root_hash(true, &empty_proof_store_v2).unwrap();
+        })
+    });
+
+    let empty_proof_store_v_experimental = ProofStoreVExperimental::default();
+    let mut v_experimental_hash = B256::ZERO;
+    let mut trie_v_experimental = TrieVExperimental::new_empty();
+    c.bench_function("insert_nodes_v_experimental", |b| {
+        b.iter(|| {
+            trie_v_experimental.clear_empty();
+            for (key, value) in keys.iter().zip(values.iter()) {
+                trie_v_experimental.insert(key, value).unwrap();
+            }
+            v_experimental_hash = trie_v_experimental
+                .root_hash(true, &empty_proof_store_v_experimental)
+                .unwrap();
+        })
+    });
+
+    if !v2_hash.is_zero() && !v_experimental_hash.is_zero() {
+        assert_eq!(v2_hash, v_experimental_hash);
+    }
+}
+
+criterion_group!(benches, insert_nodes_v2_v_experimental);
+criterion_main!(benches);