Re: [Qemu-devel] [PATCH v5 3/3] tests/migration: Add a test for auto converge

[Yury Kotov]

David,

I kept your Reviewed-by, but could you take another look at the test?
I've made many changes in it.

Thanks!

26.08.2019, 13:39, "Yury Kotov" <address@hidden>:
> Signed-off-by: Yury Kotov <address@hidden>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  tests/migration-test.c | 120 +++++++++++++++++++++++++++++++++++++----
>  1 file changed, 109 insertions(+), 11 deletions(-)
>
> diff --git a/tests/migration-test.c b/tests/migration-test.c
> index b87ba99a9e..e5caf93dfa 100644
> --- a/tests/migration-test.c
> +++ b/tests/migration-test.c
> @@ -240,6 +240,17 @@ 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");
> @@ -254,20 +265,22 @@ 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);
>      }
>  }
> @@ -1125,6 +1138,90 @@ 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;
> + int64_t remaining, percentage;
> +
> + /*
> + * We want the test to be stable and as fast as possible.
> + * E.g., with 1Gb/s bandwith migration may pass without throttling,
> + * so we need to decrease a bandwidth.
> + */
> + const int64_t init_pct = 5, inc_pct = 50, max_pct = 95;
> + const int64_t max_bandwidth = 400000000; /* ~400Mb/s */
> + const int64_t downtime_limit = 250; /* 250ms */
> + /*
> + * 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_int(from, "cpu-throttle-initial", init_pct);
> + migrate_set_parameter_int(from, "cpu-throttle-increment", inc_pct);
> + migrate_set_parameter_int(from, "max-cpu-throttle", max_pct);
> +
> + /*
> + * Set the initial parameters so that the migration could not converge
> + * without throttling.
> + */
> + migrate_set_parameter_int(from, "downtime-limit", 1);
> + migrate_set_parameter_int(from, "max-bandwidth", 100000000); /* ~100Mb/s */
> +
> + /* 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, "{}");
> +
> + /* Wait for throttling begins */
> + percentage = 0;
> + while (percentage == 0) {
> + percentage = read_migrate_property_int(from, "cpu-throttle-percentage");
> + usleep(100);
> + g_assert_false(got_stop);
> + }
> + /* The first percentage of throttling should be equal to init_pct */
> + g_assert_cmpint(percentage, ==, init_pct);
> + /* Now, when we tested that throttling works, let it converge */
> + migrate_set_parameter_int(from, "downtime-limit", downtime_limit);
> + migrate_set_parameter_int(from, "max-bandwidth", max_bandwidth);
> +
> + /*
> + * Wait for pre-switchover status to check last throttle percentage
> + * and remaining. These values will be zeroed later
> + */
> + wait_for_migration_status(from, "pre-switchover");
> +
> + /* The final percentage of throttling shouldn't be greater than max_pct */
> + percentage = read_migrate_property_int(from, "cpu-throttle-percentage");
> + g_assert_cmpint(percentage, <=, max_pct);
> +
> + 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);
> +
> + g_free(uri);
> +
> + test_migrate_end(from, to, true);
> +}
> +
>  int main(int argc, char **argv)
>  {
>      char template[] = "/tmp/migration-test-XXXXXX";
> @@ -1180,6 +1277,7 @@ 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

Regards,
Yury