On 10/22/19 3:12 AM, yezhenyu (A) wrote:
Since qemu2.9, QEMU added three AioContext poll parameters to struct
IOThread: poll_max_ns, poll_grow and poll_shrink. These properties are
used to control iothread polling time.
However, there isn't properly hmp commands to adjust them when the VM is
alive. It's useful to adjust them online when observing the impact of
different property value on performance.
This patch add three hmp commands to adjust iothread poll-* properties
for special iothread:
set_iothread_poll_max_ns: set the maximum polling time in ns;
set_iothread_poll_grow: set how many ns will be added to polling time;
set_iothread_poll_shrink: set how many ns will be removed from polling
time.
Signed-off-by: Zhenyu Ye <yezhen...@huawei.com>
---
hmp-commands.hx | 42 ++++++++++++++++++++
hmp.c | 30 +++++++++++++++
hmp.h | 3 ++
include/sysemu/iothread.h | 6 +++
iothread.c | 80 +++++++++++++++++++++++++++++++++++++++
qapi/misc.json | 23 +++++++++++
6 files changed, 184 insertions(+)
Looking at just the QMP...
+++ b/qapi/misc.json
@@ -675,6 +675,29 @@
{ 'command': 'query-iothreads', 'returns': ['IOThreadInfo'],
'allow-preconfig': true }
+##
+# @set-iothread-poll-param:
+#
+# Set poll-* properties for a special iothread.
+# The poll-* name can be poll_max_ns/poll_grow/poll_shrink.
This should be an enum.
+#
+# Notes: can not set the QEMU main loop thread, which is not declared
+# using the -object iothread command-line option. The poll_ns property can not
+# be set manually, which is auto-adjust.
You failed to document the parameters (iothread_id, name, value).
+#
+# Example:
+#
+# -> { "execute": "set-iothread-poll-param",
+# "arguments": { "iothread_id": "1",
+# "name": "poll_max_ns",
+# "value": 1000 } }
+# <- { "return": {} }
+#
+# Since 3.0
4.2 is the earliest this can make it in.
+##
+{ 'command': 'set-iothread-poll-param',
+ 'data': {'iothread_id': 'str', 'name': 'str', 'value': 'int'} }
Our naming convention prefers 'iothread-id'.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
