Re: [Qemu-devel] [PATCH 05/13] migration: Create x-multifd-threads parameter

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Juan Quintela (quintela@redhat.com) wrote:
> Indicates the number of threads that we would create.  By default we
> create 2 threads.

Is a migration with the multifd capability set and x_multifd_threads=1
the same as a normal migration, or I'm thinking it's still different in
that it has a separate data fd?

Dave

> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  hmp.c                         |  8 ++++++++
>  include/migration/migration.h |  2 ++
>  migration/migration.c         | 30 +++++++++++++++++++++++++++++-
>  qapi-schema.json              | 19 ++++++++++++++++---
>  4 files changed, 55 insertions(+), 4 deletions(-)
> 
> diff --git a/hmp.c b/hmp.c
> index d510236..2a40f1f 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -286,6 +286,9 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
>          monitor_printf(mon, " %s: %" PRId64,
>              MigrationParameter_lookup[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT],
>              params->x_cpu_throttle_increment);
> +        monitor_printf(mon, " %s: %" PRId64,
> +            MigrationParameter_lookup[MIGRATION_PARAMETER_X_MULTIFD_THREADS],
> +            params->x_multifd_threads);
>          monitor_printf(mon, "\n");
>      }
> 
> @@ -1242,6 +1245,7 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
>      bool has_decompress_threads = false;
>      bool has_x_cpu_throttle_initial = false;
>      bool has_x_cpu_throttle_increment = false;
> +    bool has_x_multifd_threads = false;
>      int i;
> 
>      for (i = 0; i < MIGRATION_PARAMETER__MAX; i++) {
> @@ -1262,12 +1266,16 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
>              case MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT:
>                  has_x_cpu_throttle_increment = true;
>                  break;
> +            case MIGRATION_PARAMETER_X_MULTIFD_THREADS:
> +                has_x_multifd_threads = true;
> +                break;
>              }
>              qmp_migrate_set_parameters(has_compress_level, value,
>                                         has_compress_threads, value,
>                                         has_decompress_threads, value,
>                                         has_x_cpu_throttle_initial, value,
>                                         has_x_cpu_throttle_increment, value,
> +                                       has_x_multifd_threads, value,
>                                         &err);
>              break;
>          }
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index a626b7d..19d535d 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -219,6 +219,8 @@ bool migration_in_postcopy(MigrationState *);
>  bool migration_in_postcopy_after_devices(MigrationState *);
>  MigrationState *migrate_get_current(void);
> 
> +int migrate_multifd_threads(void);
> +
>  void migrate_compress_threads_create(void);
>  void migrate_compress_threads_join(void);
>  void migrate_decompress_threads_create(void);
> diff --git a/migration/migration.c b/migration/migration.c
> index 92e6dc4..29e43ff 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -56,6 +56,8 @@
>  /* Migration XBZRLE default cache size */
>  #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
> 
> +#define DEFAULT_MIGRATE_MULTIFD_THREADS 2
> +
>  static NotifierList migration_state_notifiers =
>      NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
> 
> @@ -91,6 +93,8 @@ MigrationState *migrate_get_current(void)
>                  DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL,
>          .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
>                  DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT,
> +        .parameters[MIGRATION_PARAMETER_X_MULTIFD_THREADS] =
> +                DEFAULT_MIGRATE_MULTIFD_THREADS,
>      };
> 
>      if (!once) {
> @@ -521,6 +525,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
>              s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
>      params->x_cpu_throttle_increment =
>              s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
> +    params->x_multifd_threads =
> +            s->parameters[MIGRATION_PARAMETER_X_MULTIFD_THREADS];
> 
>      return params;
>  }
> @@ -717,7 +723,10 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>                                  bool has_x_cpu_throttle_initial,
>                                  int64_t x_cpu_throttle_initial,
>                                  bool has_x_cpu_throttle_increment,
> -                                int64_t x_cpu_throttle_increment, Error **errp)
> +                                int64_t x_cpu_throttle_increment,
> +                                bool has_multifd_threads,
> +                                int64_t multifd_threads,
> +                                Error **errp)
>  {
>      MigrationState *s = migrate_get_current();
> 
> @@ -753,6 +762,13 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>                     "an integer in the range of 1 to 99");
>      }
> 
> +    if (has_multifd_threads &&
> +            (multifd_threads < 1 || multifd_threads > 255)) {
> +        error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
> +                   "multifd_threads",
> +                   "is invalid, it should be in the range of 1 to 255");
> +        return;
> +    }
>      if (has_compress_level) {
>          s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
>      }
> @@ -772,6 +788,9 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>          s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
>                                                      x_cpu_throttle_increment;
>      }
> +    if (has_multifd_threads) {
> +        s->parameters[MIGRATION_PARAMETER_X_MULTIFD_THREADS] = multifd_threads;
> +    }
>  }
> 
>  void qmp_migrate_start_postcopy(Error **errp)
> @@ -1196,6 +1215,15 @@ bool migrate_multifd(void)
>      return s->enabled_capabilities[MIGRATION_CAPABILITY_X_MULTIFD];
>  }
> 
> +int migrate_multifd_threads(void)
> +{
> +    MigrationState *s;
> +
> +    s = migrate_get_current();
> +
> +    return s->parameters[MIGRATION_PARAMETER_X_MULTIFD_THREADS];
> +}
> +
>  int migrate_use_xbzrle(void)
>  {
>      MigrationState *s;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 9fdf902..6ff9ac6 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -613,11 +613,16 @@
>  # @x-cpu-throttle-increment: throttle percentage increase each time
>  #                            auto-converge detects that migration is not making
>  #                            progress. The default value is 10. (Since 2.5)
> +#
> +# @x-multifd-threads: Number of threads used to migrate data in parallel
> +#                     The default value is 1 (since 2.6)
> +#
>  # Since: 2.4
>  ##
>  { 'enum': 'MigrationParameter',
>    'data': ['compress-level', 'compress-threads', 'decompress-threads',
> -           'x-cpu-throttle-initial', 'x-cpu-throttle-increment'] }
> +           'x-cpu-throttle-initial', 'x-cpu-throttle-increment',
> +           'x-multifd-threads'] }
> 
>  #
>  # @migrate-set-parameters
> @@ -637,6 +642,10 @@
>  # @x-cpu-throttle-increment: throttle percentage increase each time
>  #                            auto-converge detects that migration is not making
>  #                            progress. The default value is 10. (Since 2.5)
> +#
> +# @x-multifd-threads: Number of threads used to migrate data in parallel
> +#                     The default value is 1 (since 2.6)
> +#
>  # Since: 2.4
>  ##
>  { 'command': 'migrate-set-parameters',
> @@ -644,7 +653,8 @@
>              '*compress-threads': 'int',
>              '*decompress-threads': 'int',
>              '*x-cpu-throttle-initial': 'int',
> -            '*x-cpu-throttle-increment': 'int'} }
> +            '*x-cpu-throttle-increment': 'int',
> +            '*x-multifd-threads': 'int'} }
> 
>  #
>  # @MigrationParameters
> @@ -663,6 +673,8 @@
>  #                            auto-converge detects that migration is not making
>  #                            progress. The default value is 10. (Since 2.5)
>  #
> +# @x-multifd-threads: Number of threads used to migrate data in parallel
> +#                     The default value is 1 (since 2.6)
>  # Since: 2.4
>  ##
>  { 'struct': 'MigrationParameters',
> @@ -670,7 +682,8 @@
>              'compress-threads': 'int',
>              'decompress-threads': 'int',
>              'x-cpu-throttle-initial': 'int',
> -            'x-cpu-throttle-increment': 'int'} }
> +            'x-cpu-throttle-increment': 'int',
> +            'x-multifd-threads': 'int'} }
>  ##
>  # @query-migrate-parameters
>  #
> -- 
> 2.5.5
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK