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Re: [Qemu-devel] [PATCH v6 07/19] migration: Create x-multifd-threads pa
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH v6 07/19] migration: Create x-multifd-threads parameter |
Date: |
Fri, 11 Aug 2017 15:56:01 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Tue, Aug 08, 2017 at 06:26:17PM +0200, Juan Quintela wrote:
> Indicates the number of threads that we would create. By default we
> create 2 threads.
>
> Signed-off-by: Juan Quintela <address@hidden>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
>
> --
>
> Catch inconsistent defaults (eric).
> Improve comment stating that number of threads is the same than number
> of sockets
> Use new DEFIN_PROP_*
> ---
> hmp.c | 7 +++++++
> migration/migration.c | 26 ++++++++++++++++++++++++++
> migration/migration.h | 1 +
> qapi-schema.json | 25 ++++++++++++++++++++++---
> 4 files changed, 56 insertions(+), 3 deletions(-)
>
> diff --git a/hmp.c b/hmp.c
> index fd80dce..7899813 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -337,6 +337,9 @@ void hmp_info_migrate_parameters(Monitor *mon, const
> QDict *qdict)
> monitor_printf(mon, "%s: %s\n",
> MigrationParameter_lookup[MIGRATION_PARAMETER_BLOCK_INCREMENTAL],
> params->block_incremental ? "on" : "off");
> + monitor_printf(mon, "%s: %" PRId64 "\n",
> + MigrationParameter_lookup[MIGRATION_PARAMETER_X_MULTIFD_THREADS],
> + params->x_multifd_threads);
> }
>
> qapi_free_MigrationParameters(params);
> @@ -1622,6 +1625,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const
> QDict *qdict)
> p->has_block_incremental = true;
> visit_type_bool(v, param, &p->block_incremental, &err);
> break;
> + case MIGRATION_PARAMETER_X_MULTIFD_THREADS:
> + p->has_x_multifd_threads = true;
> + visit_type_int(v, param, &p->x_multifd_threads, &err);
> + break;
> }
>
> if (err) {
> diff --git a/migration/migration.c b/migration/migration.c
> index 4e6ad87..6ed9600 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -78,6 +78,7 @@
> * Note: Please change this default value to 10000 when we support hybrid
> mode.
> */
> #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY 200
> +#define DEFAULT_MIGRATE_MULTIFD_THREADS 2
>
> static NotifierList migration_state_notifiers =
> NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
> @@ -483,6 +484,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error
> **errp)
> params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
> params->has_block_incremental = true;
> params->block_incremental = s->parameters.block_incremental;
> + params->has_x_multifd_threads = true;
> + params->x_multifd_threads = s->parameters.x_multifd_threads;
>
> return params;
> }
> @@ -764,6 +767,13 @@ static bool migrate_params_check(MigrationParameters
> *params, Error **errp)
> "is invalid, it should be positive");
> return false;
> }
> + if (params->has_x_multifd_threads &&
> + (params->x_multifd_threads < 1 || params->x_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 false;
> + }
>
> return true;
> }
> @@ -882,6 +892,9 @@ static void migrate_params_apply(MigrateSetParameters
> *params)
> if (params->has_block_incremental) {
> s->parameters.block_incremental = params->block_incremental;
> }
> + if (params->has_x_multifd_threads) {
> + s->parameters.x_multifd_threads = params->x_multifd_threads;
> + }
> }
>
> void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
> @@ -1459,6 +1472,15 @@ bool migrate_use_multifd(void)
> return s->enabled_capabilities[MIGRATION_CAPABILITY_X_MULTIFD];
> }
>
> +int migrate_multifd_threads(void)
> +{
> + MigrationState *s;
> +
> + s = migrate_get_current();
> +
> + return s->parameters.x_multifd_threads;
> +}
> +
> int migrate_use_xbzrle(void)
> {
> MigrationState *s;
> @@ -2224,6 +2246,9 @@ static Property migration_properties[] = {
> DEFINE_PROP_INT64("x-checkpoint-delay", MigrationState,
> parameters.x_checkpoint_delay,
> DEFAULT_MIGRATE_X_CHECKPOINT_DELAY),
> + DEFINE_PROP_INT64("x-multifd-threads", MigrationState,
> + parameters.x_multifd_threads,
> + DEFAULT_MIGRATE_MULTIFD_THREADS),
>
> /* Migration capabilities */
> DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
> @@ -2281,6 +2306,7 @@ static void migration_instance_init(Object *obj)
> params->has_downtime_limit = true;
> params->has_x_checkpoint_delay = true;
> params->has_block_incremental = true;
> + params->has_x_multifd_threads = true;
> }
>
> /*
> diff --git a/migration/migration.h b/migration/migration.h
> index b7437f1..8e4803d 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -175,6 +175,7 @@ bool migrate_zero_blocks(void);
>
> bool migrate_auto_converge(void);
> bool migrate_use_multifd(void);
> +int migrate_multifd_threads(void);
>
> int migrate_use_xbzrle(void);
> int64_t migrate_xbzrle_cache_size(void);
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 521e15c..3fe1a64 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -918,6 +918,7 @@
> #
> # @return-path: If enabled, migration will use the return path even
> # for precopy. (since 2.10)
> +#
> # @x-multifd: Use more than one fd for migration (since 2.11)
> #
> # Since: 1.2
> @@ -1043,13 +1044,19 @@
> # migrated and the destination must already have access to the
> # same backing chain as was used on the source. (since 2.10)
> #
> +# @x-multifd-threads: Number of threads used to migrate data in
> +# parallel. This is the same number that the
> +# number of sockets used for migration.
> +# The default value is 2 (since 2.11)
The feature is called "multifd" but we're configuring number of threads,
with the implicit suggestion that number of threads == number of sockets.
I wonder if its better to call this "x-multifd-connections" so that it
is explicit that we're determining the number of socket connections.
This leaves room for adapting code to use a different number of threads,
but same number of sockets. eg with post-copy, there's potential to have
2 threads for each socket (1 reading, 1 writing).
> +#
> # Since: 2.4
> ##
> { 'enum': 'MigrationParameter',
> 'data': ['compress-level', 'compress-threads', 'decompress-threads',
> 'cpu-throttle-initial', 'cpu-throttle-increment',
> 'tls-creds', 'tls-hostname', 'max-bandwidth',
> - 'downtime-limit', 'x-checkpoint-delay', 'block-incremental' ] }
> + 'downtime-limit', 'x-checkpoint-delay', 'block-incremental',
> + 'x-multifd-threads'] }
Regards,
Daniel
--
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- [Qemu-devel] [PATCH v6 04/19] migration: Create migration_has_all_channels, (continued)
- [Qemu-devel] [PATCH v6 04/19] migration: Create migration_has_all_channels, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 05/19] qio: Create new qio_channel_{readv, writev}_all, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 06/19] migration: Add multifd capability, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 07/19] migration: Create x-multifd-threads parameter, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 08/19] migration: Create x-multifd-group parameter, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 09/19] migration: Create multifd migration threads, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 10/19] migration: Split migration_fd_process_incoming, Juan Quintela, 2017/08/08
- [Qemu-devel] [PATCH v6 11/19] migration: Start of multiple fd work, Juan Quintela, 2017/08/08