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Re: [Qemu-devel] [PATCH v3 3/3] tests/migration: Add a test for auto con
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v3 3/3] tests/migration: Add a test for auto converge |
Date: |
Mon, 22 Jul 2019 18:35:25 +0100 |
User-agent: |
Mutt/1.12.0 (2019-05-25) |
* Yury Kotov (address@hidden) wrote:
> Signed-off-by: Yury Kotov <address@hidden>
This looks OK to me, but have you tried it on a really really overloaded
host?
I worry that you might skip some of the percentage steps or not hit the
bandwidth on the small overloaded VMs we get in CI.
Dave
> ---
> 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 a4feb9545d..bb69517fc8 100644
> --- a/tests/migration-test.c
> +++ b/tests/migration-test.c
> @@ -241,6 +241,17 @@ 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");
> @@ -255,20 +266,22 @@ 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);
> }
> }
> @@ -1121,6 +1134,89 @@ 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_int(from, "cpu-throttle-initial",
> expected_pcts[1]);
> + migrate_set_parameter_int(from, "cpu-throttle-increment",
> + expected_pcts[2] - expected_pcts[1]);
> + migrate_set_parameter_int(from, "max-cpu-throttle", expected_pcts[3]);
> +
> + migrate_set_parameter_int(from, "max-bandwidth", max_bandwidth);
> + migrate_set_parameter_int(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";
> @@ -1176,6 +1272,7 @@ 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
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK