From 692c24bc3dc6289de483ac167b2fc9f8aa8022c3 Mon Sep 17 00:00:00 2001
From: Ludvig Liljenberg <4257730+ludfjig@users.noreply.github.com>
Date: Wed, 10 Sep 2025 10:56:24 -0700
Subject: [PATCH] Add benchmark for measuring performance impact on moving
 sandbox across thread

Signed-off-by: Ludvig Liljenberg <4257730+ludfjig@users.noreply.github.com>
---
 src/hyperlight_host/benches/benchmarks.rs | 43 +++++++++++++++++++++++
 src/tests/rust_guests/witguest/Cargo.lock |  4 +--
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/hyperlight_host/benches/benchmarks.rs b/src/hyperlight_host/benches/benchmarks.rs
index 3ed91820f..61d405370 100644
--- a/src/hyperlight_host/benches/benchmarks.rs
+++ b/src/hyperlight_host/benches/benchmarks.rs
@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+use std::sync::Mutex;
+
 use criterion::{Criterion, criterion_group, criterion_main};
 use flatbuffers::FlatBufferBuilder;
 use hyperlight_common::flatbuffer_wrappers::function_call::{FunctionCall, FunctionCallType};
@@ -74,6 +76,47 @@ fn guest_call_benchmark(c: &mut Criterion) {
         });
     });
 
+    // same as guest_call, but the call will be made on different thread
+    group.bench_function("guest_call_on_different_thread", |b| {
+        use std::sync::{Arc, Barrier};
+        use std::thread;
+        use std::time::Instant;
+
+        b.iter_custom(|iters| {
+            let mut total_duration = std::time::Duration::ZERO;
+            let sbox = Arc::new(Mutex::new(create_multiuse_sandbox()));
+
+            for _ in 0..iters {
+                // Ensure vcpu is "bound" on this main thread
+                {
+                    let mut sbox = sbox.lock().unwrap();
+                    sbox.call::<String>("Echo", "warmup\n".to_string()).unwrap();
+                }
+
+                let barrier = Arc::new(Barrier::new(2));
+                let barrier_clone = Arc::clone(&barrier);
+                let sbox_clone = Arc::clone(&sbox);
+
+                let handle = thread::spawn(move || {
+                    barrier_clone.wait();
+
+                    let mut sbox = sbox_clone.lock().unwrap();
+                    let start = Instant::now();
+                    // Measure the first call after thread switch
+                    // According to KVM docs, this should show performance impact
+                    sbox.call::<String>("Echo", "hello\n".to_string()).unwrap();
+                    start.elapsed()
+                });
+
+                barrier.wait();
+
+                total_duration += handle.join().unwrap();
+            }
+
+            total_duration
+        });
+    });
+
     group.finish();
 }
 
diff --git a/src/tests/rust_guests/witguest/Cargo.lock b/src/tests/rust_guests/witguest/Cargo.lock
index 762a25e97..6a33cb503 100644
--- a/src/tests/rust_guests/witguest/Cargo.lock
+++ b/src/tests/rust_guests/witguest/Cargo.lock
@@ -521,9 +521,9 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
 [[package]]
 name = "wasmparser"
-version = "0.238.1"
+version = "0.239.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fa99c8328024423875ae4a55345cfde8f0371327fb2d0f33b0f52a06fc44408"
+checksum = "8c9d90bb93e764f6beabf1d02028c70a2156a6583e63ac4218dd07ef733368b0"
 dependencies = [
  "bitflags",
  "hashbrown",