test(metrics): collect Firecracker vhost-user metrics

tests/integration_tests/performance/test_vhost_user_metrics.py

@@ -0,0 +1,87 @@
+# Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+"""Tests to collect Firecracker metrics for vhost-user devices."""
+
+import time
+
+import pytest
+
+import host_tools.drive as drive_tools
+from framework.utils_drive import resize_vhost_user_drive, spawn_vhost_user_backend
+
+
+@pytest.mark.parametrize("vcpu_count", [1, 2], ids=["1vcpu", "2vcpu"])
+def test_vhost_user_block_metrics(
+    microvm_factory, guest_kernel, rootfs_ubuntu_22, vcpu_count, metrics
+):
+    """
+    This test tries to boot a VM with vhost-user-block
+    as a scratch device, resize the vhost-user scratch drive to have
+    config change notifications, collects and then uploads the related
+    vhost-user FirecrackerMetrics to Cloudwatch.
+    Having vhost-user as root device vs a scratch should not impact metrics, however,
+    we choose to have it as a scratch device because we are interested in config change
+    metrics which we cannot extract when vhost-user is root device
+    (read only rootfs won't have a config change).
+    """
+    orig_size = 10  # MB
+    # Picked from test_config_change assuming that the intention is to change size from
+    # low->high->low->high and so the numbers are not in monotonic sequence.
+    new_sizes = [20, 10, 30]  # MB
+    vhost_user_socket = "/vub.socket"
+
+    vm = microvm_factory.build(guest_kernel, rootfs_ubuntu_22, monitor_memory=False)
+    vm.spawn(log_level="Info")
+    vm.basic_config(vcpu_count=vcpu_count)
+
+    # Add a block device to test resizing.
+    fs = drive_tools.FilesystemFile(size=orig_size)
+    _backend = spawn_vhost_user_backend(vm, fs.path, vhost_user_socket)
+    vm.add_vhost_user_drive("scratch", vhost_user_socket)
+    vm.start()
+
+    # vhost-user-block is activated during boot but it takes a while so we wait.
+    # 300msec picked by the limited number of experiments tried to see how long
+    # it takes to get the activate_time_us metrics.
+    time.sleep(0.3)
+
+    metrics.set_dimensions(
+        {
+            "performance_test": "vhost_user_block_metrics",
+            "io_engine": "vhost-user",
+            **vm.dimensions,
+        }
+    )
+    fc_metrics = vm.flush_metrics()
+    assert 0 == fc_metrics["vhost_user_block_scratch"]["activate_fails"]
+    assert fc_metrics["vhost_user_block_scratch"]["init_time_us"]
+    assert fc_metrics["vhost_user_block_scratch"]["activate_time_us"]
+
+    metrics.put_metric(
+        "init_time_us",
+        fc_metrics["vhost_user_block_scratch"]["init_time_us"],
+        unit="Microseconds",
+    )
+    metrics.put_metric(
+        "activate_time_us",
+        fc_metrics["vhost_user_block_scratch"]["activate_time_us"],
+        unit="Microseconds",
+    )
+
+    for new_size in new_sizes:
+        # Instruct the backend to resize the device.
+        # It will both resize the file and update its device config.
+        resize_vhost_user_drive(vm, new_size)
+
+        # Instruct Firecracker to reread device config and notify
+        # the guest of a config change.
+        vm.patch_drive("scratch")
+
+        fc_metrics = vm.flush_metrics()
+        assert 0 == fc_metrics["vhost_user_block_scratch"]["cfg_fails"]
+        assert fc_metrics["vhost_user_block_scratch"]["config_change_time_us"]
+        metrics.put_metric(
+            "config_change_time_us",
+            fc_metrics["vhost_user_block_scratch"]["config_change_time_us"],
+            unit="Microseconds",
+        )