Re: [PATCH v1 6/7] qapi/migration: Introduce cpu-responsive-throttle parameter

[Fabiano Rosas <farosas@suse.de>]

Hyman Huang <yong.huang@smartx.com> writes:

> To enable the responsive throttle that will be implemented
> in the next commit, introduce the cpu-responsive-throttle
> parameter.
>
> Signed-off-by: Hyman Huang <yong.huang@smartx.com>
> ---
>  migration/migration-hmp-cmds.c |  8 ++++++++
>  migration/options.c            | 20 ++++++++++++++++++++
>  migration/options.h            |  1 +
>  qapi/migration.json            | 16 +++++++++++++++-
>  4 files changed, 44 insertions(+), 1 deletion(-)
>
> diff --git a/migration/migration-hmp-cmds.c b/migration/migration-hmp-cmds.c
> index 28165cfc9e..1fe6c74d66 100644
> --- a/migration/migration-hmp-cmds.c
> +++ b/migration/migration-hmp-cmds.c
> @@ -264,6 +264,10 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
>          monitor_printf(mon, "%s: %s\n",
>              MigrationParameter_str(MIGRATION_PARAMETER_CPU_THROTTLE_TAILSLOW),
>              params->cpu_throttle_tailslow ? "on" : "off");
> +        assert(params->has_cpu_responsive_throttle);
> +        monitor_printf(mon, "%s: %s\n",
> +            MigrationParameter_str(MIGRATION_PARAMETER_CPU_RESPONSIVE_THROTTLE),
> +            params->cpu_responsive_throttle ? "on" : "off");
>          assert(params->has_max_cpu_throttle);
>          monitor_printf(mon, "%s: %u\n",
>              MigrationParameter_str(MIGRATION_PARAMETER_MAX_CPU_THROTTLE),
> @@ -512,6 +516,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
>          p->has_cpu_throttle_tailslow = true;
>          visit_type_bool(v, param, &p->cpu_throttle_tailslow, &err);
>          break;
> +    case MIGRATION_PARAMETER_CPU_RESPONSIVE_THROTTLE:
> +        p->has_cpu_responsive_throttle = true;
> +        visit_type_bool(v, param, &p->cpu_responsive_throttle, &err);
> +        break;
>      case MIGRATION_PARAMETER_MAX_CPU_THROTTLE:
>          p->has_max_cpu_throttle = true;
>          visit_type_uint8(v, param, &p->max_cpu_throttle, &err);
> diff --git a/migration/options.c b/migration/options.c
> index 147cd2b8fd..b4c269bf1d 100644
> --- a/migration/options.c
> +++ b/migration/options.c
> @@ -111,6 +111,8 @@ Property migration_properties[] = {
>                        DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT),
>      DEFINE_PROP_BOOL("x-cpu-throttle-tailslow", MigrationState,
>                        parameters.cpu_throttle_tailslow, false),
> +    DEFINE_PROP_BOOL("x-cpu-responsive-throttle", MigrationState,
> +                      parameters.cpu_responsive_throttle, false),
>      DEFINE_PROP_SIZE("x-max-bandwidth", MigrationState,
>                        parameters.max_bandwidth, MAX_THROTTLE),
>      DEFINE_PROP_SIZE("avail-switchover-bandwidth", MigrationState,
> @@ -705,6 +707,13 @@ uint8_t migrate_cpu_throttle_initial(void)
>      return s->parameters.cpu_throttle_initial;
>  }
>  
> +bool migrate_responsive_throttle(void)
> +{
> +    MigrationState *s = migrate_get_current();
> +
> +    return s->parameters.cpu_responsive_throttle;
> +}
> +
>  bool migrate_cpu_throttle_tailslow(void)
>  {
>      MigrationState *s = migrate_get_current();
> @@ -891,6 +900,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
>      params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
>      params->has_cpu_throttle_tailslow = true;
>      params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
> +    params->has_cpu_responsive_throttle = true;
> +    params->cpu_responsive_throttle = s->parameters.cpu_responsive_throttle;
>      params->tls_creds = g_strdup(s->parameters.tls_creds);
>      params->tls_hostname = g_strdup(s->parameters.tls_hostname);
>      params->tls_authz = g_strdup(s->parameters.tls_authz ?
> @@ -959,6 +970,7 @@ void migrate_params_init(MigrationParameters *params)
>      params->has_cpu_throttle_initial = true;
>      params->has_cpu_throttle_increment = true;
>      params->has_cpu_throttle_tailslow = true;
> +    params->has_cpu_responsive_throttle = true;
>      params->has_max_bandwidth = true;
>      params->has_downtime_limit = true;
>      params->has_x_checkpoint_delay = true;
> @@ -1191,6 +1203,10 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
>          dest->cpu_throttle_tailslow = params->cpu_throttle_tailslow;
>      }
>  
> +    if (params->has_cpu_responsive_throttle) {
> +        dest->cpu_responsive_throttle = params->cpu_responsive_throttle;
> +    }
> +
>      if (params->tls_creds) {
>          assert(params->tls_creds->type == QTYPE_QSTRING);
>          dest->tls_creds = params->tls_creds->u.s;
> @@ -1302,6 +1318,10 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
>          s->parameters.cpu_throttle_tailslow = params->cpu_throttle_tailslow;
>      }
>  
> +    if (params->has_cpu_responsive_throttle) {
> +        s->parameters.cpu_responsive_throttle = params->cpu_responsive_throttle;
> +    }
> +
>      if (params->tls_creds) {
>          g_free(s->parameters.tls_creds);
>          assert(params->tls_creds->type == QTYPE_QSTRING);
> diff --git a/migration/options.h b/migration/options.h
> index a0bd6edc06..80d0fcdaf9 100644
> --- a/migration/options.h
> +++ b/migration/options.h
> @@ -68,6 +68,7 @@ bool migrate_has_block_bitmap_mapping(void);
>  uint32_t migrate_checkpoint_delay(void);
>  uint8_t migrate_cpu_throttle_increment(void);
>  uint8_t migrate_cpu_throttle_initial(void);
> +bool migrate_responsive_throttle(void);
>  bool migrate_cpu_throttle_tailslow(void);
>  bool migrate_direct_io(void);
>  uint64_t migrate_downtime_limit(void);
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 95b490706c..c61d3b3a6b 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -732,6 +732,10 @@
>  #     be excessive at tail stage.  The default value is false.  (Since
>  #     5.1)
>  #
> +# @cpu-responsive-throttle: Make CPU throttling more responsively by
> +#                           introduce an extra detection metric of
> +#                           migration convergence. (Since 9.1)
> +#
>  # @tls-creds: ID of the 'tls-creds' object that provides credentials
>  #     for establishing a TLS connection over the migration data
>  #     channel.  On the outgoing side of the migration, the credentials
> @@ -857,7 +861,7 @@
>             'announce-rounds', 'announce-step',
>             'throttle-trigger-threshold',
>             'cpu-throttle-initial', 'cpu-throttle-increment',
> -           'cpu-throttle-tailslow',
> +           'cpu-throttle-tailslow', 'cpu-responsive-throttle',
>             'tls-creds', 'tls-hostname', 'tls-authz', 'max-bandwidth',
>             'avail-switchover-bandwidth', 'downtime-limit',
>             { 'name': 'x-checkpoint-delay', 'features': [ 'unstable' ] },
> @@ -913,6 +917,10 @@
>  #     be excessive at tail stage.  The default value is false.  (Since
>  #     5.1)
>  #
> +# @cpu-responsive-throttle: Make CPU throttling more responsively by
> +#                           introduce an extra detection metric of
> +#                           migration convergence. (Since 9.1)
> +#
>  # @tls-creds: ID of the 'tls-creds' object that provides credentials
>  #     for establishing a TLS connection over the migration data
>  #     channel.  On the outgoing side of the migration, the credentials
> @@ -1045,6 +1053,7 @@
>              '*cpu-throttle-initial': 'uint8',
>              '*cpu-throttle-increment': 'uint8',
>              '*cpu-throttle-tailslow': 'bool',
> +            '*cpu-responsive-throttle': 'bool',

Should this instead follow the pattern of cpu-throttle-* ?

>              '*tls-creds': 'StrOrNull',
>              '*tls-hostname': 'StrOrNull',
>              '*tls-authz': 'StrOrNull',
> @@ -1127,6 +1136,10 @@
>  #     be excessive at tail stage.  The default value is false.  (Since
>  #     5.1)
>  #
> +# @cpu-responsive-throttle: Make CPU throttling more responsively by

s/responsively/responsive/ ?

> +#                           introduce an extra detection metric of
> +#                           migration convergence. (Since 9.1)

Since 9.2. And double space after period.

> +#
>  # @tls-creds: ID of the 'tls-creds' object that provides credentials
>  #     for establishing a TLS connection over the migration data
>  #     channel.  On the outgoing side of the migration, the credentials
> @@ -1252,6 +1265,7 @@
>              '*cpu-throttle-initial': 'uint8',
>              '*cpu-throttle-increment': 'uint8',
>              '*cpu-throttle-tailslow': 'bool',
> +            '*cpu-responsive-throttle': 'bool',
>              '*tls-creds': 'str',
>              '*tls-hostname': 'str',
>              '*tls-authz': 'str',