trace_event_add_filter
retval = trace_event_add_filter(params->common.events, optarg);
retval = trace_event_add_filter(params->common.events, optarg);
retval = trace_event_add_filter(params->common.events, optarg);
retval = trace_event_add_filter(params->common.events, optarg);
int trace_event_add_filter(struct trace_events *event, char *filter);