Re: [Qemu-devel] [RFC 0/3] qemu-ga: support for sending events

[Marc-André Lureau]

Hi

On Fri, Jun 23, 2017 at 3:03 PM Tomáš Golembiovský <address@hidden>
wrote:

> This is just a draft, or a request for comments if you will.
>
> This patch sets drafts the support of sending events by QEMU Guest Agent.
> Events can plan important role in monitoring of the guest OS behaviour. The
> range of use cases ranges from events important for scheduling, e.g.
> memory and
> CPU usage statistics, to things like changes to IP addresses on network
> interfaces to for example changes in the list of active users.
>
> For now the patch set adds single periodic callback function to the GA main
> loop that can perform checks and trigger events that have occured since
> previous run of the callback.
>
> We can of course take it one step further and add a general framwork for
> periodically running any of the already implemented commands. Add a
> function
> that would maintain a list of registered checks. Client would use some
> command
> (register-monitor-command) passing it a command name and timeout in
> seconds and
> the monitoring handler would then run the specified command and report the
> result... or report only if the return value changed since previous
> invocation.
> This feature would remove part of the communication overhead between
> client and
> GA.
>
> So before I invest any more time in either of these approaches, tell me.
> Would
> somethign like this be wanted or is that too controversial? Any other
> thoughts
> and ideas?
>
>
It doesn't feel wrong, but Is there really too much overhead and/or latency
if a request is periodic from the client? ie did you do some measurements
before coming to this proposal?

Tomáš Golembiovský (3):
>   qemu-ga: add support for events
>   qemu-ga: add simple event reporting memory statistics
>   qemu-ga: add support for periodic command runner
>
>  Makefile               |  7 +++-
>  qga/Makefile.objs      |  2 +-
>  qga/channel-posix.c    |  8 +++++
>  qga/channel-win32.c    |  6 ++++
>  qga/channel.h          |  1 +
>  qga/guest-agent-core.h |  1 +
>  qga/main.c             | 98
> ++++++++++++++++++++++++++++++++++++++++++++++++++
>  qga/qapi-event.json    | 35 ++++++++++++++++++
>  qga/qapi-schema.json   |  2 ++
>  9 files changed, 158 insertions(+), 2 deletions(-)
>  create mode 100644 qga/qapi-event.json
>
> --
> 2.13.1
>
>
> --
Marc-André Lureau