[Qemu-devel] [PATCH 2/3] migration: Add qmp command for migrate_set_max_cpu_throttle

[Li Qiang]

The default max cpu throttle is 99, this is too big that may
influence the guest loads. Add a qmp to config it can make it
more flexible.

Signed-off-by: Li Qiang <address@hidden>
---
 cpus.c                |  5 +++++
 include/qom/cpu.h     |  8 ++++++++
 migration/migration.c | 10 ++++++++++
 qapi/migration.json   | 13 +++++++++++++
 4 files changed, 36 insertions(+)

diff --git a/cpus.c b/cpus.c
index 6569c73d24..0505477086 100644
--- a/cpus.c
+++ b/cpus.c
@@ -765,6 +765,11 @@ void cpu_throttle_set(int new_throttle_pct)
                                        CPU_THROTTLE_TIMESLICE_NS);
 }
 
+void set_cpu_max_throttle(int64_t max_pct)
+{
+    throttle_percentage_max = max_pct;
+}
+
 void cpu_throttle_stop(void)
 {
     atomic_set(&throttle_percentage, 0);
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index bd796579ee..4328d2e8ad 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -816,6 +816,14 @@ CPUState *cpu_by_arch_id(int64_t id);
 void cpu_throttle_set(int new_throttle_pct);
 
 /**
+ * set_cpu_max_throttle:
+ * @max_pct: the max percent of sleep time. Valid range is 1 to 99.
+ *
+ * Set the max throttle percentage.
+ */
+void set_cpu_max_throttle(int64_t max_pct);
+
+/**
  * cpu_throttle_stop:
  *
  * Stops the vcpu throttling started by cpu_throttle_set.
diff --git a/migration/migration.c b/migration/migration.c
index b7d9854bda..9c7a6f7477 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1774,6 +1774,16 @@ void qmp_migrate_set_speed(int64_t value, Error **errp)
     qmp_migrate_set_parameters(&p, errp);
 }
 
+void qmp_migrate_set_max_cpu_throttle(int64_t value, Error **errp)
+{
+    if (value > 99 || value < 1) {
+        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, " max cpu throttle",
+                        "not in 1 between 99");
+        return;
+    }
+    set_cpu_max_throttle(value);
+}
+
 void qmp_migrate_set_downtime(double value, Error **errp)
 {
     if (value < 0 || value > MAX_MIGRATE_DOWNTIME_SECONDS) {
diff --git a/qapi/migration.json b/qapi/migration.json
index 186e8a7303..2ef3ddfe43 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -997,6 +997,19 @@
 { 'command': 'migrate_set_speed', 'data': {'value': 'int'} }
 
 ##
+# @migrate_set_max_cpu_throttle:
+#
+# Set maximum cpu throttle for migration.
+#
+# @value: maximum cpu throttle.
+#
+# Returns: nothing on success
+#
+# Since: 2.12
+##
+{ 'command': 'migrate_set_max_cpu_throttle', 'data': {'value': 'int'} }
+
+##
 # @migrate-set-cache-size:
 #
 # Set cache size to be used by XBZRLE migration
-- 
2.11.0