[Qemu-devel] [PATCH v2 3/3] tests/migration: Add a test for auto converge

[Yury Kotov]

Signed-off-by: Yury Kotov <address@hidden>
---
 tests/migration-test.c | 119 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 108 insertions(+), 11 deletions(-)

diff --git a/tests/migration-test.c b/tests/migration-test.c
index e0407576cb..8a755dfaf2 100644
--- a/tests/migration-test.c
+++ b/tests/migration-test.c
@@ -250,6 +250,17 @@ static int64_t read_ram_property_int(QTestState *who, 
const char *property)
     return result;
 }
 
+static int64_t read_migrate_property_int(QTestState *who, const char *property)
+{
+    QDict *rsp_return;
+    int64_t result;
+
+    rsp_return = migrate_query(who);
+    result = qdict_get_try_int(rsp_return, property, 0);
+    qobject_unref(rsp_return);
+    return result;
+}
+
 static uint64_t get_migration_pass(QTestState *who)
 {
     return read_ram_property_int(who, "dirty-sync-count");
@@ -264,20 +275,22 @@ static void read_blocktime(QTestState *who)
     qobject_unref(rsp_return);
 }
 
+static bool check_migration_status(QTestState *who, const char *status)
+{
+    bool completed;
+    char *current_status;
+
+    current_status = migrate_query_status(who);
+    completed = strcmp(current_status, status) == 0;
+    g_assert_cmpstr(current_status, !=, "failed");
+    g_free(current_status);
+    return completed;
+}
+
 static void wait_for_migration_status(QTestState *who,
                                       const char *goal)
 {
-    while (true) {
-        bool completed;
-        char *status;
-
-        status = migrate_query_status(who);
-        completed = strcmp(status, goal) == 0;
-        g_assert_cmpstr(status, !=,  "failed");
-        g_free(status);
-        if (completed) {
-            return;
-        }
+    while (!check_migration_status(who, goal)) {
         usleep(1000);
     }
 }
@@ -1127,6 +1140,89 @@ static void test_migrate_fd_proto(void)
     test_migrate_end(from, to, true);
 }
 
+static void test_migrate_auto_converge(void)
+{
+    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
+    QTestState *from, *to;
+    int i;
+    int64_t remaining, downtime;
+
+    /*
+     * We want the test to be fast enough, but stable.
+     * Throttle percentages are chosen to cover all cases (init, increment, 
max)
+     */
+    static const int64_t expected_pcts[] = { 0, 1, 51, 98 };
+    const int64_t max_bandwidth = 200000000; /* ~200Mb/s */
+    const int64_t downtime_limit = 50; /* 50ms */
+    /*
+     * We migrate through unix-socket (> 500Mb/s).
+     * Thus, expected migration speed ~= bandwidth limit (< 500Mb/s).
+     * So, we can predict expected_threshold
+     */
+    const int64_t expected_threshold = max_bandwidth * downtime_limit / 1000;
+
+    if (test_migrate_start(&from, &to, uri, false, false)) {
+        return;
+    }
+
+    migrate_set_capability(from, "auto-converge", true);
+    migrate_set_parameter(from, "cpu-throttle-initial", expected_pcts[1]);
+    migrate_set_parameter(from, "cpu-throttle-increment",
+                          expected_pcts[2] - expected_pcts[1]);
+    migrate_set_parameter(from, "max-cpu-throttle", expected_pcts[3]);
+
+    migrate_set_parameter(from, "max-bandwidth", max_bandwidth);
+    migrate_set_parameter(from, "downtime-limit", downtime_limit);
+
+    /* To check remaining size after precopy */
+    migrate_set_capability(from, "pause-before-switchover", true);
+
+    /* Wait for the first serial output from the source */
+    wait_for_serial("src_serial");
+
+    migrate(from, uri, "{}");
+
+    for (i = 0; i < ARRAY_SIZE(expected_pcts); i++) {
+        int64_t pct;
+        pct = read_migrate_property_int(from, "cpu-throttle-percentage");
+        g_assert_cmpint(pct, ==, expected_pcts[i]);
+        while (pct == expected_pcts[i] && !got_stop) {
+            usleep(1000);
+            pct = read_migrate_property_int(from, "cpu-throttle-percentage");
+        }
+        /* We break out of this loop only in paused state */
+        if (got_stop || i + 1 == ARRAY_SIZE(expected_pcts)) {
+            /* Check unexpected throttle percentage change */
+            g_assert_true(got_stop);
+            /* Check unexpected converge */
+            g_assert_cmpint(i + 1, ==, ARRAY_SIZE(expected_pcts));
+            g_assert_true(check_migration_status(from, "pre-switchover"));
+        }
+    }
+
+    remaining = read_ram_property_int(from, "remaining");
+    g_assert_cmpint(remaining, <, expected_threshold);
+
+    wait_command(from, "{ 'execute': 'migrate-continue' , 'arguments':"
+                       "  { 'state': 'pre-switchover' } }");
+
+    qtest_qmp_eventwait(to, "RESUME");
+
+    wait_for_serial("dest_serial");
+    wait_for_migration_complete(from);
+
+    downtime = read_migrate_property_int(from, "downtime");
+    /*
+     * Actual downtime may be greater than downtime limit,
+     * but the difference should be small enough (~20ms)
+     */
+    g_assert_cmpint(downtime, <, downtime_limit + 20);
+
+    g_free(uri);
+
+    test_migrate_end(from, to, true);
+}
+
 int main(int argc, char **argv)
 {
     char template[] = "/tmp/migration-test-XXXXXX";
@@ -1182,6 +1278,7 @@ int main(int argc, char **argv)
     /* qtest_add_func("/migration/ignore_shared", test_ignore_shared); */
     qtest_add_func("/migration/xbzrle/unix", test_xbzrle_unix);
     qtest_add_func("/migration/fd_proto", test_migrate_fd_proto);
+    qtest_add_func("/migration/auto_converge", test_migrate_auto_converge);
 
     ret = g_test_run();
 
-- 
2.22.0