[Qemu-devel] [PATCH v7 2/5] migration: Parameters for auto-converge cpu throttling

["Jason J. Herne" <jjherne@linux.vnet.ibm.com>]

Add migration parameters to allow the user to adjust the parameters
that control cpu throttling when auto-converge is in effect. The added
parameters are as follows:

x-cpu-throttle-initial : Initial percantage of time guest cpus are throttled
when migration auto-converge is activated.

x-cpu-throttle-increment: throttle percantage increase each time
auto-converge detects that migration is not making progress.

Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hmp.c                 | 16 ++++++++++++++++
 migration/migration.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 qapi-schema.json      | 33 ++++++++++++++++++++++++++++++---
 3 files changed, 91 insertions(+), 4 deletions(-)

diff --git a/hmp.c b/hmp.c
index e17852d..eb65998 100644
--- a/hmp.c
+++ b/hmp.c
@@ -269,6 +269,12 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, " %s: %" PRId64,
             MigrationParameter_lookup[MIGRATION_PARAMETER_DECOMPRESS_THREADS],
             params->decompress_threads);
+        monitor_printf(mon, " %s: %" PRId64,
+            MigrationParameter_lookup[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL],
+            params->x_cpu_throttle_initial);
+        monitor_printf(mon, " %s: %" PRId64,
+            MigrationParameter_lookup[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT],
+            params->x_cpu_throttle_increment);
         monitor_printf(mon, "\n");
     }
 
@@ -1216,6 +1222,8 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
     bool has_compress_level = false;
     bool has_compress_threads = false;
     bool has_decompress_threads = false;
+    bool has_x_cpu_throttle_initial = false;
+    bool has_x_cpu_throttle_increment = false;
     int i;
 
     for (i = 0; i < MIGRATION_PARAMETER_MAX; i++) {
@@ -1230,10 +1238,18 @@ void hmp_migrate_set_parameter(Monitor *mon, const QDict *qdict)
             case MIGRATION_PARAMETER_DECOMPRESS_THREADS:
                 has_decompress_threads = true;
                 break;
+            case MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL:
+                has_x_cpu_throttle_initial = true;
+                break;
+            case MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT:
+                has_x_cpu_throttle_increment = 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,
                                        &err);
             break;
         }
diff --git a/migration/migration.c b/migration/migration.c
index 732d229..05790e9 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -40,6 +40,9 @@
 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
+/* Define default autoconverge cpu throttle migration parameters */
+#define DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL 20
+#define DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT 10
 
 /* Migration XBZRLE default cache size */
 #define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
@@ -66,6 +69,10 @@ MigrationState *migrate_get_current(void)
                 DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
         .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
                 DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
+        .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
+                DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL,
+        .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
+                DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT,
     };
 
     return &current_migration;
@@ -199,6 +206,10 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
             s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
     params->decompress_threads =
             s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
+    params->x_cpu_throttle_initial =
+            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
+    params->x_cpu_throttle_increment =
+            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
 
     return params;
 }
@@ -321,7 +332,11 @@ void qmp_migrate_set_parameters(bool has_compress_level,
                                 bool has_compress_threads,
                                 int64_t compress_threads,
                                 bool has_decompress_threads,
-                                int64_t decompress_threads, Error **errp)
+                                int64_t decompress_threads,
+                                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)
 {
     MigrationState *s = migrate_get_current();
 
@@ -344,6 +359,18 @@ void qmp_migrate_set_parameters(bool has_compress_level,
                   "is invalid, it should be in the range of 1 to 255");
         return;
     }
+    if (has_x_cpu_throttle_initial &&
+            (x_cpu_throttle_initial < 1 || x_cpu_throttle_initial > 99)) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE,
+                  "x_cpu_throttle_initial",
+                  "an integer in the range of 1 to 99");
+    }
+    if (has_x_cpu_throttle_increment &&
+            (x_cpu_throttle_increment < 1 || x_cpu_throttle_increment > 99)) {
+        error_set(errp, QERR_INVALID_PARAMETER_VALUE,
+                  "x_cpu_throttle_increment",
+                  "an integer in the range of 1 to 99");
+    }
 
     if (has_compress_level) {
         s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
@@ -355,6 +382,15 @@ void qmp_migrate_set_parameters(bool has_compress_level,
         s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
                                                     decompress_threads;
     }
+    if (has_x_cpu_throttle_initial) {
+        s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
+                                                    x_cpu_throttle_initial;
+    }
+
+    if (has_x_cpu_throttle_increment) {
+        s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
+                                                    x_cpu_throttle_increment;
+    }
 }
 
 /* shared migration helpers */
@@ -470,6 +506,10 @@ static MigrationState *migrate_init(const MigrationParams *params)
             s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
     int decompress_thread_count =
             s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
+    int x_cpu_throttle_initial =
+            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
+    int x_cpu_throttle_increment =
+            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
 
     memcpy(enabled_capabilities, s->enabled_capabilities,
            sizeof(enabled_capabilities));
@@ -485,6 +525,10 @@ static MigrationState *migrate_init(const MigrationParams *params)
                compress_thread_count;
     s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
                decompress_thread_count;
+    s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
+                x_cpu_throttle_initial;
+    s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
+                x_cpu_throttle_increment;
     s->bandwidth_limit = bandwidth_limit;
     s->state = MIGRATION_STATUS_SETUP;
     trace_migrate_set_state(MIGRATION_STATUS_SETUP);
diff --git a/qapi-schema.json b/qapi-schema.json
index f97ffa1..6eba9ed 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -587,10 +587,18 @@
 #          compression, so set the decompress-threads to the number about 1/4
 #          of compress-threads is adequate.
 #
+# @x-cpu-throttle-initial: Initial percentage of time guest cpus are throttled
+#                          when migration auto-converge is activated. The
+#                          default value is 20. (Since 2.5)
+#
+# @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)
 # Since: 2.4
 ##
 { 'enum': 'MigrationParameter',
-  'data': ['compress-level', 'compress-threads', 'decompress-threads'] }
+  'data': ['compress-level', 'compress-threads', 'decompress-threads',
+           'x-cpu-throttle-initial', 'x-cpu-throttle-increment'] }
 
 #
 # @migrate-set-parameters
@@ -603,12 +611,21 @@
 #
 # @decompress-threads: decompression thread count
 #
+# @x-cpu-throttle-initial: Initial percentage of time guest cpus are throttled
+#                          when migration auto-converge is activated. The
+#                          default value is 20. (Since 2.5)
+#
+# @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)
 # Since: 2.4
 ##
 { 'command': 'migrate-set-parameters',
   'data': { '*compress-level': 'int',
             '*compress-threads': 'int',
-            '*decompress-threads': 'int'} }
+            '*decompress-threads': 'int',
+            '*x-cpu-throttle-initial': 'int',
+            '*x-cpu-throttle-increment': 'int'} }
 
 #
 # @MigrationParameters
@@ -619,12 +636,22 @@
 #
 # @decompress-threads: decompression thread count
 #
+# @x-cpu-throttle-initial: Initial percentage of time guest cpus are throttled
+#                          when migration auto-converge is activated. The
+#                          default value is 20. (Since 2.5)
+#
+# @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)
+#
 # Since: 2.4
 ##
 { 'struct': 'MigrationParameters',
   'data': { 'compress-level': 'int',
             'compress-threads': 'int',
-            'decompress-threads': 'int'} }
+            'decompress-threads': 'int',
+            'x-cpu-throttle-initial': 'int',
+            'x-cpu-throttle-increment': 'int'} }
 ##
 # @query-migrate-parameters
 #
-- 
1.9.1