Re: [PATCH 4/5] tests: use consistent bandwidth/downtime limits in migration tests

[Dr. David Alan Gilbert]

* Daniel P. Berrangé (berrange@redhat.com) wrote:
> The different migration test cases are using a variety of settings
> to ensure convergance/non-convergance. Introduce two helpers to
> extra the common functionality and ensure consistency.
> 
>   * Non-convergance: 1ms downtime, 30mbs bandwidth
>   * Convergance: 30s downtime, 1gbs bandwidth
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  tests/qtest/migration-test.c | 54 +++++++++++++-----------------------
>  1 file changed, 20 insertions(+), 34 deletions(-)
> 
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index a54eff6d56..9e64125f02 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -46,9 +46,6 @@ unsigned start_address;
>  unsigned end_address;
>  static bool uffd_feature_thread_id;
>  
> -/* A downtime where the test really should converge */
> -#define CONVERGE_DOWNTIME (1000 * 30)
> -
>  #if defined(__linux__)
>  #include <sys/syscall.h>
>  #include <sys/vfs.h>
> @@ -402,6 +399,20 @@ static void migrate_set_parameter_str(QTestState *who, 
> const char *parameter,
>      migrate_check_parameter_str(who, parameter, value);
>  }
>  
> +static void migrate_ensure_non_converge(QTestState *who)
> +{
> +    /* Can't converge with 1ms downtime + 30 mbs bandwidth limit */
> +    migrate_set_parameter_int(who, "max-bandwidth", 30 * 1000 * 1000);
> +    migrate_set_parameter_int(who, "downtime-limit", 1);
> +}
> +
> +static void migrate_ensure_converge(QTestState *who)
> +{
> +    /* Should converge with 30s downtime + 1 gbs bandwidth limit */
> +    migrate_set_parameter_int(who, "max-bandwidth", 1 * 1000 * 1000 * 1000);
> +    migrate_set_parameter_int(who, "downtime-limit", 30 * 1000);
> +}
> +
>  static void migrate_pause(QTestState *who)
>  {
>      QDict *rsp;
> @@ -984,12 +995,7 @@ static int migrate_postcopy_prepare(QTestState 
> **from_ptr,
>      migrate_set_capability(to, "postcopy-ram", true);
>      migrate_set_capability(to, "postcopy-blocktime", true);
>  
> -    /* We want to pick a speed slow enough that the test completes
> -     * quickly, but that it doesn't complete precopy even on a slow
> -     * machine, so also set the downtime.
> -     */
> -    migrate_set_parameter_int(from, "max-bandwidth", 30000000);
> -    migrate_set_parameter_int(from, "downtime-limit", 1);
> +    migrate_ensure_non_converge(from);
>  
>      /* Wait for the first serial output from the source */
>      wait_for_serial("src_serial");
> @@ -1188,15 +1194,7 @@ static void test_precopy_common(MigrateCommon *args)
>          return;
>      }
>  
> -    /*
> -     * We want to pick a speed slow enough that the test completes
> -     * quickly, but that it doesn't complete precopy even on a slow
> -     * machine, so also set the downtime.
> -     */
> -    /* 1 ms should make it not converge*/
> -    migrate_set_parameter_int(from, "downtime-limit", 1);
> -    /* 1GB/s */
> -    migrate_set_parameter_int(from, "max-bandwidth", 1000000000);
> +    migrate_ensure_non_converge(from);
>  
>      if (args->start_hook) {
>          data_hook = args->start_hook(from, to);
> @@ -1230,7 +1228,7 @@ static void test_precopy_common(MigrateCommon *args)
>              wait_for_migration_pass(from);
>          }
>  
> -        migrate_set_parameter_int(from, "downtime-limit", CONVERGE_DOWNTIME);
> +        migrate_ensure_converge(from);
>  
>          /* We do this first, as it has a timeout to stop us
>           * hanging forever if migration didn't converge */
> @@ -1694,8 +1692,7 @@ static void test_migrate_auto_converge(void)
>       * 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 
> */
> +    migrate_ensure_non_converge(from);
>  
>      /* To check remaining size after precopy */
>      migrate_set_capability(from, "pause-before-switchover", true);
> @@ -2000,15 +1997,7 @@ static void test_multifd_tcp_cancel(void)
>          return;
>      }
>  
> -    /*
> -     * We want to pick a speed slow enough that the test completes
> -     * quickly, but that it doesn't complete precopy even on a slow
> -     * machine, so also set the downtime.
> -     */
> -    /* 1 ms should make it not converge*/
> -    migrate_set_parameter_int(from, "downtime-limit", 1);
> -    /* 300MB/s */
> -    migrate_set_parameter_int(from, "max-bandwidth", 30000000);
> +    migrate_ensure_non_converge(from);
>  
>      migrate_set_parameter_int(from, "multifd-channels", 16);
>      migrate_set_parameter_int(to, "multifd-channels", 16);
> @@ -2054,10 +2043,7 @@ static void test_multifd_tcp_cancel(void)
>  
>      wait_for_migration_status(from, "cancelled", NULL);
>  
> -    /* 300ms it should converge */
> -    migrate_set_parameter_int(from, "downtime-limit", 300);
> -    /* 1GB/s */
> -    migrate_set_parameter_int(from, "max-bandwidth", 1000000000);
> +    migrate_ensure_converge(from);
>  
>      migrate_qmp(from, uri, "{}");
>  
> -- 
> 2.36.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK