* Zhenyu Ye (yezhen...@huawei.com) wrote: > > > On 2019/10/23 23:19, Stefan Hajnoczi wrote: > > On Tue, Oct 22, 2019 at 04:12:03PM +0800, 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(+) > > > > poll-max-ns, poll-grow, poll-shrink are properties of IOThread objects. > > They can already be modified at runtime using: > > > > $ qemu -object iothread,id=iothread1 > > (qemu) qom-set /objects/iothread1 poll-max-ns 100000 > > > > I think there is no need for a patch. > > > > Stefan > > > > Thanks for your review. I have considered using the `qom-set` command to > modify > IOThread object's properties, however, this command is not friendly to primary > users. The help info for this command is only: > > qom-set path property value -- set QOM property > > It's almost impossible to get the correct `path` parameter for primary user.
Is this just a matter of documenting how to do it? It sounds like there's no need for a new QMP command though; if you want an easier HMP command I'd probably still take it (because HMP is ok at having things for convenience) - but not if it turns out that just adding a paragraph of documentation is enough. Dave > This patch provides a more convenient and easy-use hmp&qmp interface to modify > these IOThread properties. I think this patch still has a little value. > > And I can implement this patch compactly by reusing your code. > > Waiting for your reply. > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK