diff --git a/Cargo.toml b/Cargo.toml
index 5b8584e..3069720 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,7 +15,11 @@ test = false
 bench = false
 
 [[bench]]
-name = "bench"
+name = "engine_bench"
+harness = false
+
+[[bench]]
+name = "threadpool_bench"
 harness = false
 
 
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4506e7e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,4 @@
+# KV-store
+
+Based on [Talent Plan, an open source training program initiated by PingCAPcourse](https://github.com/pingcap/talent-plan),
+"TP 201: Practical Networked Applications in Rust"
diff --git a/benches/bench.rs b/benches/engine_bench.rs
similarity index 93%
rename from benches/bench.rs
rename to benches/engine_bench.rs
index 1919192..273c30c 100644
--- a/benches/bench.rs
+++ b/benches/engine_bench.rs
@@ -13,7 +13,7 @@ fn set_bench(c: &mut Criterion) {
                 let store = KvStore::open(temp_dir.path()).expect("unable to open kvstore");
                 store
             },
-            |mut store| {
+            |store| {
                 for i in 1..(1 << 12) {
                     store.set(format!("key{i}"), format!("value{i}")).unwrap();
                 }
@@ -29,7 +29,7 @@ fn set_bench(c: &mut Criterion) {
                 let store = SledKvsEngine::open(temp_dir.path()).expect("unable to open kvstore");
                 store
             },
-            |mut store| {
+            |store| {
                 for i in 1..(1 << 12) {
                     store.set(format!("key{i}"), format!("value{i}")).unwrap();
                 }
@@ -45,7 +45,7 @@ fn get_bench(c: &mut Criterion) {
     for i in &vec![8, 12, 16, 20] {
         group.bench_with_input(format!("kvs_{i}"), i, |b, i| {
             let temp_dir = TempDir::new().unwrap();
-            let mut store = KvStore::open(temp_dir.path()).unwrap();
+            let store = KvStore::open(temp_dir.path()).unwrap();
             for key_i in 1..(1 << i) {
                 store
                     .set(format!("key{key_i}"), format!("value{key_i}"))
@@ -63,7 +63,7 @@ fn get_bench(c: &mut Criterion) {
     for i in &vec![8, 12, 16, 20] {
         group.bench_with_input(format!("sled_{i}"), i, |b, i| {
             let temp_dir = TempDir::new().unwrap();
-            let mut store = SledKvsEngine::open(temp_dir.path()).unwrap();
+            let store = SledKvsEngine::open(temp_dir.path()).unwrap();
             for key_i in 1..(1 << i) {
                 store
                     .set(format!("key{key_i}"), format!("value{key_i}"))
diff --git a/benches/threadpool_bench.rs b/benches/threadpool_bench.rs
new file mode 100644
index 0000000..273c30c
--- /dev/null
+++ b/benches/threadpool_bench.rs
@@ -0,0 +1,84 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use rand::{rngs::SmallRng, Rng, SeedableRng};
+use tempfile::TempDir;
+use trash_db::engines::{kvstore::KvStore, sled::SledKvsEngine, KvsEngine};
+
+fn set_bench(c: &mut Criterion) {
+    let mut group = c.benchmark_group("set_bench");
+    group.bench_function("kvs", |b| {
+        b.iter_batched(
+            || {
+                let temp_dir =
+                    TempDir::new().expect("unable to create temporary working directory");
+                let store = KvStore::open(temp_dir.path()).expect("unable to open kvstore");
+                store
+            },
+            |store| {
+                for i in 1..(1 << 12) {
+                    store.set(format!("key{i}"), format!("value{i}")).unwrap();
+                }
+            },
+            criterion::BatchSize::SmallInput,
+        )
+    });
+    group.bench_function("sled", |b| {
+        b.iter_batched(
+            || {
+                let temp_dir =
+                    TempDir::new().expect("unable to create temporary working directory");
+                let store = SledKvsEngine::open(temp_dir.path()).expect("unable to open kvstore");
+                store
+            },
+            |store| {
+                for i in 1..(1 << 12) {
+                    store.set(format!("key{i}"), format!("value{i}")).unwrap();
+                }
+            },
+            criterion::BatchSize::SmallInput,
+        )
+    });
+    group.finish();
+}
+
+fn get_bench(c: &mut Criterion) {
+    let mut group = c.benchmark_group("set_bench");
+    for i in &vec![8, 12, 16, 20] {
+        group.bench_with_input(format!("kvs_{i}"), i, |b, i| {
+            let temp_dir = TempDir::new().unwrap();
+            let store = KvStore::open(temp_dir.path()).unwrap();
+            for key_i in 1..(1 << i) {
+                store
+                    .set(format!("key{key_i}"), format!("value{key_i}"))
+                    .unwrap();
+            }
+            let mut rng = SmallRng::from_seed([0; 16]);
+            b.iter(|| {
+                store
+                    .get(format!("key{}", rng.gen_range(1, 1 << i)))
+                    .unwrap();
+            })
+        });
+    }
+
+    for i in &vec![8, 12, 16, 20] {
+        group.bench_with_input(format!("sled_{i}"), i, |b, i| {
+            let temp_dir = TempDir::new().unwrap();
+            let store = SledKvsEngine::open(temp_dir.path()).unwrap();
+            for key_i in 1..(1 << i) {
+                store
+                    .set(format!("key{key_i}"), format!("value{key_i}"))
+                    .unwrap();
+            }
+            let mut rng = SmallRng::from_seed([0; 16]);
+            b.iter(|| {
+                store
+                    .get(format!("key{}", rng.gen_range(1, 1 << i)))
+                    .unwrap();
+            })
+        });
+    }
+    group.finish();
+}
+
+criterion_group!(benches, set_bench, get_bench);
+criterion_main!(benches);