[Qemu-devel] [RFC][PATCH 12/14 v4] support to set dumping speed

[Wen Congyang <wency@cn.fujitsu.com>]

Add API to allow the user to control dumping speed

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 dump.c           |   12 ++++++++++++
 hmp-commands.hx  |   15 +++++++++++++++
 hmp.c            |    6 ++++++
 hmp.h            |    1 +
 qapi-schema.json |   15 +++++++++++++++
 qmp-commands.hx  |   22 ++++++++++++++++++++++
 6 files changed, 71 insertions(+), 0 deletions(-)

diff --git a/dump.c b/dump.c
index 3848d25..2131e22 100644
--- a/dump.c
+++ b/dump.c
@@ -85,6 +85,7 @@ typedef struct DumpState {
 } DumpState;
 
 #define DEFAULT_THROTTLE  (32 << 20)      /* Default dump speed throttling */
+#define MIN_THROTTLE  (1 << 10)       /* Miniumum dump speed */
 
 static DumpState *dump_get_current(void)
 {
@@ -734,3 +735,14 @@ void qmp_dump_cancel(Error **errp)
     dump_cleanup(s);
     return;
 }
+
+void qmp_dump_set_speed(int64_t value, Error **errp)
+{
+    DumpState *s = dump_get_current();
+
+    if (value < MIN_THROTTLE) {
+        value = MIN_THROTTLE;
+    }
+    s->bandwidth = value;
+    return;
+}
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 83d40b6..20543dd 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -858,6 +858,21 @@ Cancel the current VM dumping.
 ETEXI
 
     {
+        .name       = "dump_set_speed",
+        .args_type  = "value:o",
+        .params     = "value",
+        .help       = "set maximum speed (in bytes) for dumping. "
+        "Defaults to MB if no size suffix is specified, ie. B/K/M/G/T",
+        .mhandler.cmd = hmp_dump_set_speed,
+    },
+
+STEXI
+@item dump_set_speed @var{value}
+@findex dump_set_speed
+Set maximum speed to @var{value} (in bytes) for dumping.
+ETEXI
+
+    {
         .name       = "snapshot_blkdev",
         .args_type  = "device:B,snapshot-file:s?,format:s?",
         .params     = "device [new-image-file] [format]",
diff --git a/hmp.c b/hmp.c
index 7fc89db..be64075 100644
--- a/hmp.c
+++ b/hmp.c
@@ -684,3 +684,9 @@ void hmp_dump_cancel(Monitor *mon, const QDict *qdict)
 {
     qmp_dump_cancel(NULL);
 }
+
+void hmp_dump_set_speed(Monitor *mon, const QDict *qdict)
+{
+    int64_t value = qdict_get_int(qdict, "value");
+    qmp_dump_set_speed(value, NULL);
+}
diff --git a/hmp.h b/hmp.h
index 409e809..3aa947c 100644
--- a/hmp.h
+++ b/hmp.h
@@ -50,5 +50,6 @@ void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
 void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
 void hmp_dump_cancel(Monitor *mon, const QDict *qdict);
+void hmp_dump_set_speed(Monitor *mon, const QDict *qdict);
 
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index f5f79b0..ca324d6 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1288,3 +1288,18 @@
 # Since: 1.1
 ##
 { 'command': 'dump_cancel' }
+
+##
+# @dump_set_speed
+#
+# Set maximum speed for dumping.
+#
+# @value: maximum speed in bytes.
+#
+# Returns: nothing on success
+#
+# Notes: A value lesser than 1024 will be automatically round up to 1024.
+#
+# Since: 1.1
+##
+{ 'command': 'dump_set_speed', 'data': {'value': 'int'} }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 5207a41..6f84cdc 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -620,6 +620,28 @@ Example:
 EQMP
 
     {
+        .name       = "dump_set_speed",
+        .args_type  = "value:o",
+        .mhandler.cmd_new = qmp_marshal_input_dump_set_speed,
+    },
+
+SQMP
+dump_set_speed
+
+Set maximum speed for dumping.
+
+Arguments:
+
+- "value": maximum speed, in bytes per second (json-int)
+
+Example:
+
+-> { "execute": "dump_set_speed", "arguments": { "value": 1024 } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "netdev_add",
         .args_type  = "netdev:O",
         .params     = "[user|tap|socket],id=str[,prop=value][,...]",
-- 
1.7.1