test(virtio-mem): add performance test

Add a performance test that measures the latency to hot(un)plug
different amounts of memory.

Signed-off-by: Riccardo Mancini <mancio@amazon.com>

Author: Manciukic

tests/framework/microvm.py

@@ -1207,16 +1207,22 @@ def wait_for_ssh_up(self):
     def hotplug_memory(
         self, requested_size_mib: int, timeout: int = 60, poll: float = 0.1
     ):
-        """Send a hot(un)plug request and wait up to timeout seconds for completion polling every poll seconds"""
+        """Send a hot(un)plug request and wait up to timeout seconds for completion polling every poll seconds
+
+        Returns: api latency (secs), total latency (secs)
+        """
+        api_start = time.time()
         self.api.memory_hotplug.patch(requested_size_mib=requested_size_mib)
+        api_end = time.time()
         # Wait for the hotplug to complete
         deadline = time.time() + timeout
         while time.time() < deadline:
             if (
                 self.api.memory_hotplug.get().json()["plugged_size_mib"]
                 == requested_size_mib
             ):
-                return
+                plug_end = time.time()
+                return api_end - api_start, plug_end - api_start
             time.sleep(poll)
         raise TimeoutError(f"Hotplug did not complete within {timeout} seconds")
 

tests/integration_tests/performance/test_hotplug_memory.py

@@ -14,6 +14,7 @@
 
 from framework.guest_stats import MeminfoGuest
 from framework.microvm import HugePagesConfig
+from framework.properties import global_props
 from framework.utils import get_kernel_version, get_resident_memory
 
 MEMHP_BOOTARGS = "console=ttyS0 reboot=k panic=1 memhp_default_state=online_movable"
@@ -290,3 +291,76 @@ def test_snapshot_restore_persistence(uvm_plain_6_1, microvm_factory):
     assert checksum_before == checksum_after, "Checksums didn't match"
 
     validate_metrics(restored_vm)
+
+
+def timed_memory_hotplug(uvm, size, metrics, metric_prefix, fc_metric_name):
+    """Wait for all memory hotplug events to be processed"""
+
+    uvm.flush_metrics()
+
+    api_time, total_time = uvm.hotplug_memory(size)
+
+    fc_metrics = uvm.flush_metrics()
+
+    metrics.put_metric(
+        f"{metric_prefix}_api_time",
+        api_time,
+        unit="Seconds",
+    )
+    metrics.put_metric(
+        f"{metric_prefix}_total_time",
+        total_time,
+        unit="Seconds",
+    )
+    metrics.put_metric(
+        f"{metric_prefix}_fc_time",
+        fc_metrics["memory_hotplug"][fc_metric_name]["sum_us"],
+        unit="Microseconds",
+    )
+
+
+@pytest.mark.nonci
+@pytest.mark.parametrize(
+    "hotplug_size",
+    [
+        1024,
+        2048,
+        4096,
+        8192,
+        16384,
+    ],
+)
+@pytest.mark.parametrize(
+    "huge_pages",
+    [HugePagesConfig.NONE, HugePagesConfig.HUGETLBFS_2MB],
+)
+def test_memory_hotplug_latency(
+    microvm_factory, guest_kernel_linux_6_1, rootfs, hotplug_size, huge_pages, metrics
+):
+    """Test the latency of hotplugging memory"""
+
+    for i in range(20):
+        config = {
+            "total_size_mib": hotplug_size,
+            "slot_size_mib": 128,
+            "block_size_mib": 2,
+        }
+        uvm_plain_6_1 = microvm_factory.build(guest_kernel_linux_6_1, rootfs, pci=True)
+        uvm = uvm_booted_memhp(uvm_plain_6_1, None, None, False, config, None, None)
+
+        if i == 0:
+            metrics.set_dimensions(
+                {
+                    "instance": global_props.instance,
+                    "cpu_model": global_props.cpu_model,
+                    "host_kernel": f"linux-{global_props.host_linux_version}",
+                    "performance_test": "test_memory_hotplug_latency",
+                    "hotplug_size": str(hotplug_size),
+                    "huge_pages": huge_pages,
+                    **uvm.dimensions,
+                }
+            )
+
+        timed_memory_hotplug(uvm, hotplug_size, metrics, "hotplug", "plug_agg")
+        timed_memory_hotplug(uvm, 0, metrics, "hotunplug", "unplug_agg")
+        timed_memory_hotplug(uvm, hotplug_size, metrics, "hotplug_2nd", "plug_agg")