Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions

[Lluís Vilanova]

Daniel P Berrange writes:

> On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
>> An explicit if/else is clearer than arithmetic assuming #true is 1,
>> while the compiler should be able to generate just as optimal code.
>> 
>> Signed-off-by: Lluís Vilanova <address@hidden>
>> ---
>> stubs/trace-control.c  |    9 +++++++--
>> trace/control-target.c |   18 ++++++++++++++----
>> 2 files changed, 21 insertions(+), 6 deletions(-)
>> 
>> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
>> index 3740c38..099c2b5 100644
>> --- a/stubs/trace-control.c
>> +++ b/stubs/trace-control.c
>> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool 
>> state)
>> TraceEventID id;
>> assert(trace_event_get_state_static(ev));
>> id = trace_event_get_id(ev);
>> -    trace_events_enabled_count += state - trace_events_dstate[id];
>> -    trace_events_dstate[id] = state;
>> +    if (state) {
>> +        trace_events_enabled_count++;
>> +        trace_events_dstate[id] = 1;
>> +    } else {
>> +        trace_events_enabled_count--;

> SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
> as it is possible to call this method for a trace event that is a per-vcpu
> event

The "stub" code will never have vCPUs around, it's used by qemu-img and the like
(any program without "target" code).

I can send a v4 explicitly commenting that if you think that's necessary.


Thanks,
  Lluis