feat: add jailer performance tests

The test measures p50 and p90 of jailer startup
time. It is parametrized by the number of jailers
starting up and the number of bind mount points present
in the system.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

tests/integration_tests/performance/test_jailer.py

@@ -0,0 +1,81 @@
+# Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+"""Performance benchmark for the jailer."""
+
+import os
+import shutil
+import subprocess
+
+import pytest
+
+from framework.jailer import DEFAULT_CHROOT_PATH, JailerContext
+
+
+@pytest.mark.nonci
+@pytest.mark.parametrize("jailers", [1, 100, 300, 500])
+@pytest.mark.parametrize("mounts", [0, 100, 300, 500])
+def test_jailer_startup(jailer_time_bin, microvm_factory, jailers, mounts, metrics):
+    """
+    Test the overhead of jailer startup without and with bind mounts
+    """
+
+    jailer_binary = microvm_factory.jailer_binary_path
+
+    # Create bind mount points. The exact location of them
+    # does not matter, they just need to exist.
+    mounts_paths = "/tmp/mounts"
+    os.makedirs(mounts_paths)
+    for m in range(mounts):
+        mount_path = f"{mounts_paths}/mount{m}"
+        os.makedirs(mount_path)
+        subprocess.run(
+            ["mount", "--bind", f"{mount_path}", f"{mount_path}"], check=True
+        )
+
+    metrics.set_dimensions(
+        {
+            "performance_test": "test_boottime",
+            "jailers": jailers,
+            "mounts": mounts,
+        }
+    )
+
+    # Testing 1 jailer will give 1 data point which is not enough,
+    # so do 100 runs in this case.
+    if jailers == 1:
+        iterations = 100
+    else:
+        iterations = 1
+
+    for i in range(iterations):
+        processes = []
+        for j in range(jailers):
+            jailer = JailerContext(
+                jailer_id=f"fakefc{i}{j}",
+                exec_file=jailer_time_bin,
+                # Don't deamonize to get the stdout
+                daemonize=False,
+            )
+            jailer.setup()
+
+            cmd = [str(jailer_binary), *jailer.construct_param_list()]
+            processes.append(
+                subprocess.Popen(
+                    cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False
+                )
+            )
+
+        for p in processes:
+            r = p.communicate()[0]
+            e, s = r.split()
+            metrics.put_metric(
+                "startup",
+                int(e) - int(s),
+                unit="Microseconds",
+            )
+
+    # Cleanup mounts and jailer dirs
+    for d in os.listdir(mounts_paths):
+        subprocess.run(["umount", f"{mounts_paths}/{d}"], check=True)
+    shutil.rmtree(mounts_paths)
+    shutil.rmtree(DEFAULT_CHROOT_PATH)