[RESEND,RFC,10/10] tests/migration-tests: Add test case for responsive CPU throttle

Commit Message

Hyman Huang Sept. 9, 2024, 2:25 p.m. UTC

Despite the fact that the responsive CPU throttle is enabled,
the dirty sync count may not always increase because this is
an optimization that might not happen in any situation.

This test case just making sure it doesn't interfere with any
current functionality.

Signed-off-by: Hyman Huang <[e-mail]>
---
 tests/qtest/migration-test.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

Patch

diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index 4626301435..cf0b1dcb50 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -718,6 +718,7 @@  typedef struct {
 typedef struct {
     /* CPU throttle parameters */
     bool periodic;
+    bool responsive;
 } AutoConvergeArgs;
 
 static int test_migrate_start(QTestState **from, QTestState **to,
@@ -2795,6 +2796,7 @@  static void test_migrate_auto_converge_args(AutoConvergeArgs *input_args)
     QTestState *from, *to;
     int64_t percentage;
     bool periodic = (input_args && input_args->periodic);
+    bool responsive = (input_args && input_args->responsive);
 
     /*
      * We want the test to be stable and as fast as possible.
@@ -2820,6 +2822,16 @@  static void test_migrate_auto_converge_args(AutoConvergeArgs *input_args)
                 periodic_throttle_interval);
     }
 
+    if (responsive) {
+        /*
+         * The dirty-sync-count may not always go down while using responsive
+         * throttle because it is an optimization and may not take effect in
+         * any scenario. Just making sure this feature doesn't break any
+         * existing functionality by turning it on.
+         */
+        migrate_set_parameter_bool(from, "cpu-responsive-throttle", true);
+    }
+
     /*
      * Set the initial parameters so that the migration could not converge
      * without throttling.
@@ -2902,6 +2914,12 @@  static void test_migrate_auto_converge_periodic_throttle(void)
     test_migrate_auto_converge_args(&args);
 }
 
+static void test_migrate_auto_converge_responsive_throttle(void)
+{
+    AutoConvergeArgs args = {.responsive = true};
+    test_migrate_auto_converge_args(&args);
+}
+
 static void *
 test_migrate_precopy_tcp_multifd_start_common(QTestState *from,
                                               QTestState *to,
@@ -3955,6 +3973,8 @@  int main(int argc, char **argv)
                            test_migrate_auto_converge);
         migration_test_add("/migration/auto_converge_periodic_throttle",
                            test_migrate_auto_converge_periodic_throttle);
+        migration_test_add("/migration/auto_converge_responsive_throttle",
+                           test_migrate_auto_converge_responsive_throttle);
         if (g_str_equal(arch, "x86_64") &&
             has_kvm && kvm_dirty_ring_supported()) {
             migration_test_add("/migration/dirty_limit",