From d75bd1675c463103701d1f057e885c6724bca91a Mon Sep 17 00:00:00 2001
From: Anatol Belski <anbelski@linux.microsoft.com>
Date: Mon, 15 Dec 2025 20:14:50 +0100
Subject: [PATCH] performance-metrics: Add QCOW2 backing file performance test

Add sequential and random read performance tests for QCOW2 overlays
with QCOW2 backing files.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
---
 performance-metrics/src/main.rs              | 32 +++++++++++++++++++-
 performance-metrics/src/performance_tests.rs | 16 ++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/performance-metrics/src/main.rs b/performance-metrics/src/main.rs
index 79c0699cf..e25a84d34 100644
--- a/performance-metrics/src/main.rs
+++ b/performance-metrics/src/main.rs
@@ -319,7 +319,7 @@ mod adjuster {
     }
 }
 
-const TEST_LIST: [PerformanceTest; 30] = [
+const TEST_LIST: [PerformanceTest; 32] = [
     PerformanceTest {
         name: "boot_time_ms",
         func_ptr: performance_boot_time,
@@ -710,6 +710,36 @@ const TEST_LIST: [PerformanceTest; 30] = [
         },
         unit_adjuster: adjuster::identity,
     },
+    PerformanceTest {
+        name: "block_qcow2_backing_qcow2_read_MiBps",
+        func_ptr: performance_block_io,
+        control: PerformanceTestControl {
+            num_queues: Some(1),
+            queue_size: Some(128),
+            block_control: Some(BlockControl {
+                fio_ops: FioOps::Read,
+                bandwidth: true,
+                test_file: OVERLAY_WITH_QCOW2_BACKING,
+            }),
+            ..PerformanceTestControl::default()
+        },
+        unit_adjuster: adjuster::Bps_to_MiBps,
+    },
+    PerformanceTest {
+        name: "block_qcow2_backing_qcow2_random_read_MiBps",
+        func_ptr: performance_block_io,
+        control: PerformanceTestControl {
+            num_queues: Some(1),
+            queue_size: Some(128),
+            block_control: Some(BlockControl {
+                fio_ops: FioOps::RandomRead,
+                bandwidth: true,
+                test_file: OVERLAY_WITH_QCOW2_BACKING,
+            }),
+            ..PerformanceTestControl::default()
+        },
+        unit_adjuster: adjuster::Bps_to_MiBps,
+    },
 ];
 
 fn run_test_with_timeout(
diff --git a/performance-metrics/src/performance_tests.rs b/performance-metrics/src/performance_tests.rs
index 049310a09..140703701 100644
--- a/performance-metrics/src/performance_tests.rs
+++ b/performance-metrics/src/performance_tests.rs
@@ -33,6 +33,8 @@ enum Error {
 // The test image cannot be created on tmpfs (e.g. /tmp) filesystem,
 // as tmpfs does not support O_DIRECT
 pub const BLK_IO_TEST_IMG: &str = "/var/tmp/ch-blk-io-test.img";
+const QCOW2_BACKING_FILE: &str = "/var/tmp/ch-blk-io-test-qcow2-backing.qcow2";
+pub const OVERLAY_WITH_QCOW2_BACKING: &str = "/var/tmp/ch-blk-io-test-overlay-qcow2.qcow2";
 
 pub fn init_tests(overrides: &PerformanceTestOverrides) {
     let mut cmd = format!("dd if=/dev/zero of={BLK_IO_TEST_IMG} bs=1M count=4096");
@@ -54,11 +56,25 @@ pub fn init_tests(overrides: &PerformanceTestOverrides) {
     }
 
     assert!(exec_host_command_output(&cmd).status.success());
+
+    // QCOW2 backing file for backing file tests
+    cmd = format!("qemu-img create -f qcow2 -o preallocation=full {QCOW2_BACKING_FILE} 4G");
+    assert!(exec_host_command_output(&cmd).status.success());
+
+    // QCOW2 overlay with QCOW2 backing
+    cmd = format!(
+        "qemu-img create -f qcow2 -b {QCOW2_BACKING_FILE} -F qcow2 {OVERLAY_WITH_QCOW2_BACKING} 4G"
+    );
+    assert!(exec_host_command_output(&cmd).status.success());
 }
 
 pub fn cleanup_tests() {
     fs::remove_file(BLK_IO_TEST_IMG)
         .unwrap_or_else(|_| panic!("Failed to remove file '{BLK_IO_TEST_IMG}'."));
+    fs::remove_file(QCOW2_BACKING_FILE)
+        .unwrap_or_else(|_| panic!("Failed to remove file '{QCOW2_BACKING_FILE}'."));
+    fs::remove_file(OVERLAY_WITH_QCOW2_BACKING)
+        .unwrap_or_else(|_| panic!("Failed to remove file '{OVERLAY_WITH_QCOW2_BACKING}'."));
 }
 
 // Performance tests are expected to be executed sequentially, so we can