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

[Hyman Huang <yong.huang@smartx.com>]

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',
             '*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
+#                           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
@@ -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',
-- 
2.39.1