[Qemu-devel] [RFC PATCH v2 10/12] mc: expose tunable parameter for checkpointing frequency

[mrhines@linux.vnet.ibm.com]

From: "Michael R. Hines" <mrhines@us.ibm.com>

This exposes a QMP command that allows the management software
or policy to control the frequency of micro-checkpointing.

Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
---
 hmp-commands.hx  | 16 +++++++++++++++-
 hmp.c            |  6 ++++++
 hmp.h            |  1 +
 qapi-schema.json | 13 +++++++++++++
 qmp-commands.hx  | 23 +++++++++++++++++++++++
 5 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index f3fc514..2066c76 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -888,7 +888,7 @@ ETEXI
 		      "\n\t\t\t -b for migration without shared storage with"
 		      " full copy of disk\n\t\t\t -i for migration without "
 		      "shared storage with incremental copy of disk "
-		      "(base image shared between src and destination)",
+ 		      "(base image shared between src and destination)",
         .mhandler.cmd = hmp_migrate,
     },
 
@@ -965,6 +965,20 @@ Set maximum tolerated downtime (in seconds) for migration.
 ETEXI
 
     {
+        .name       = "migrate-set-mc-delay",
+        .args_type  = "value:i",
+        .params     = "value",
+        .help       = "Set maximum delay (in milliseconds) between micro-checkpoints",
+        .mhandler.cmd = hmp_migrate_set_mc_delay,
+    },
+
+STEXI
+@item migrate-set-mc-delay @var{millisecond}
+@findex migrate-set-mc-delay
+Set maximum delay (in milliseconds) between micro-checkpoints.
+ETEXI
+
+    {
         .name       = "migrate_set_capability",
         .args_type  = "capability:s,state:b",
         .params     = "capability state",
diff --git a/hmp.c b/hmp.c
index edf062e..9880bc8 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1029,6 +1029,12 @@ void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
     qmp_migrate_set_downtime(value, NULL);
 }
 
+void hmp_migrate_set_mc_delay(Monitor *mon, const QDict *qdict)
+{
+    int64_t value = qdict_get_int(qdict, "value");
+    qmp_migrate_set_mc_delay(value, NULL);
+}
+
 void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict)
 {
     int64_t value = qdict_get_int(qdict, "value");
diff --git a/hmp.h b/hmp.h
index ed58f0e..068b2c1 100644
--- a/hmp.h
+++ b/hmp.h
@@ -60,6 +60,7 @@ void hmp_drive_mirror(Monitor *mon, const QDict *qdict);
 void hmp_drive_backup(Monitor *mon, const QDict *qdict);
 void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
+void hmp_migrate_set_mc_delay(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index 7306adc..98abdac 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2160,6 +2160,19 @@
 { 'command': 'migrate_set_downtime', 'data': {'value': 'number'} }
 
 ##
+# @migrate-set-mc-delay
+#
+# Set delay (in milliseconds) between micro checkpoints.
+#
+# @value: maximum delay in milliseconds 
+#
+# Returns: nothing on success
+#
+# Since: 2.x
+##
+{ 'command': 'migrate-set-mc-delay', 'data': {'value': 'int'} }
+
+##
 # @migrate_set_speed
 #
 # Set maximum speed for migration.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index cce6b81..d8b9c34 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -754,6 +754,29 @@ Example:
 EQMP
 
     {
+        .name       = "migrate-set-mc-delay",
+        .args_type  = "value:i",
+        .mhandler.cmd_new = qmp_marshal_input_migrate_set_mc_delay,
+    },
+
+SQMP
+migrate-set-mc-delay
+--------------------
+
+Set maximum delay (in milliseconds) between micro-checkpoints.
+
+Arguments:
+
+- "value": maximum delay (json-int)
+
+Example:
+
+-> { "execute": "migrate-set-mc-delay", "arguments": { "value": 100 } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "client_migrate_info",
         .args_type  = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
         .params     = "protocol hostname port tls-port cert-subject",
-- 
1.8.1.2