Re: [Qemu-devel] [PATCH v9 4/7] trace: [monitor] Use new event control interface

[Stefan Hajnoczi]

On Wed, Jan 23, 2013 at 06:01:29PM +0100, Lluís Vilanova wrote:
> Stefan Hajnoczi writes:
> 
> > On Thu, Jan 10, 2013 at 08:23:19PM +0100, Lluís Vilanova wrote:
> >> Signed-off-by: Lluís Vilanova <address@hidden>
> >> ---
> >> monitor.c |   20 +++++++++++++++++---
> >> 1 file changed, 17 insertions(+), 3 deletions(-)
> >> 
> >> diff --git a/monitor.c b/monitor.c
> >> index 9cf419b..4c40541 100644
> >> --- a/monitor.c
> >> +++ b/monitor.c
> >> @@ -735,10 +735,24 @@ static void do_trace_event_set_state(Monitor *mon, 
> >> const QDict *qdict)
> >> {
> >> const char *tp_name = qdict_get_str(qdict, "name");
> >> bool new_state = qdict_get_bool(qdict, "option");
> >> -    int ret = trace_event_set_state(tp_name, new_state);
> >> 
> >> -    if (!ret) {
> >> -        monitor_printf(mon, "unknown event name \"%s\"\n", tp_name);
> >> +    if (trace_event_is_pattern(tp_name)) {
> >> +        TraceEvent *ev = NULL;
> >> +        while ((ev = trace_event_pattern(tp_name, ev)) != NULL) {
> >> +            if (!trace_event_get_state_static(ev)) {
> >> +                monitor_printf(mon, "event \"%s\" is not traceable\n", 
> >> tp_name);
> >> +            }
> >> +            trace_event_set_state_dynamic(ev, new_state);
> >> +        }
> >> +    } else {
> >> +        TraceEvent *ev = trace_event_name(tp_name);
> >> +        if (ev == NULL) {
> >> +            monitor_printf(mon, "unknown event name \"%s\"\n", tp_name);
> >> +        } else if (!trace_event_get_state_static(ev)) {
> >> +            monitor_printf(mon, "event \"%s\" is not traceable\n", 
> >> tp_name);
> >> +        } else {
> >> +            trace_event_set_state_dynamic(ev, new_state);
> >> +        }
> 
> > Do we need to duplicate the pattern vs not-a-pattern case?
> 
> > We can loop with trace_event_pattern() and print the "unknown event
> > name" only if !trace_event_is_pattern().
> 
> You mean something like this?
> 
> 
> #v+
>     bool found = false;
>     TraceEvent *ev = NULL;
>     while ((ev = trace_event_pattern(tp_name, ev)) != NULL) {
>         found = true;
>         if (!trace_event_get_state_static(ev)) {
>             monitor_printf(mon, "event \"%s\" is not traceable\n", tp_name);
>         } else {
>             trace_event_set_state_dynamic(ev, new_state);
>         }
>     }
>     if (!trace_event_is_pattern(tp_name) && !found) {
>         monitor_printf(mon, "unknown event name \"%s\"\n", tp_name);
>     }
> #v-

Yes, exactly.  It's nice to have a single code path.

Stefan