Re: [patch v0] qapi/qmp: Add timestamps to qmp command responses.

[Vladimir Sementsov-Ogievskiy]

On 9/26/22 12:59, Denis Plotnikov wrote:
> Add "start" & "end" timestamps to qmp command responses.
> It's disabled by default, but can be enabled with 'timestamp=on'
> monitor's parameter, e.g.:
>      -chardev  socket,id=mon1,path=/tmp/qmp.socket,server=on,wait=off
>      -mon chardev=mon1,mode=control,timestamp=on
>
> Example of result:
>
>      ./qemu/scripts/qmp/qmp-shell /tmp/qmp.socket
>
>      (QEMU) query-status
>      {"end": {"seconds": 1650367305, "microseconds": 831032},
>       "start": {"seconds": 1650367305, "microseconds": 831012},
>       "return": {"status": "running", "singlestep": false, "running": true}}
>
> The responce of the qmp command contains the start & end time of
> the qmp command processing.
>
> These times may be helpful for the management layer in understanding of
> the actual timeline of a qmp command processing.
>
> Suggested-by: Andrey Ryabinin <arbn@yandex-team.ru>
> Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

> ---
>   include/monitor/monitor.h   |  2 +-
>   include/qapi/qmp/dispatch.h |  2 +-
>   monitor/monitor-internal.h  |  1 +
>   monitor/monitor.c           |  9 ++++++++-
>   monitor/qmp.c               |  5 +++--
>   qapi/control.json           |  3 +++
>   qapi/qmp-dispatch.c         | 28 +++++++++++++++++++++++++++-

[..]

>   QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request,
> -                    bool allow_oob, Monitor *cur_mon)
> +                    bool allow_oob, bool timestamp, Monitor *cur_mon)
>   {
>       Error *err = NULL;
>       bool oob;
> @@ -146,6 +162,11 @@ QDict *qmp_dispatch(const QmpCommandList *cmds, QObject 
> *request,
>       QObject *id;
>       QObject *ret = NULL;
>       QDict *rsp = NULL;
> +    uint64_t ts_start = -1;
> +
> +    if (timestamp) {
> +        ts_start = g_get_real_time();
> +    }

Maybe, better start timing in handle_qmp_command(), to inlude waiting in the 
mon->qmp_requests queue.

>   
>       dict = qobject_to(QDict, request);
>       if (!dict) {
> @@ -270,5 +291,10 @@ out:
>           qdict_put_obj(rsp, "id", qobject_ref(id));
>       }
>   
> +    if (timestamp) {
> +        uint64_t ts_end = g_get_real_time();
> +        add_timestamps(rsp, ts_start, ts_end);
> +    }
> +
>       return rsp;
>   }


--
Best regards,
Vladimir