perf intel-pt: Cater for CBR change in PSB+

PSB+ provides status information only so the core-to-bus ratio (CBR) in
PSB+ will not have changed from its previous value. However, cater for
the possibility of a another CBR change that gets caught up in the PSB+
anyway.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190622093248.581-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

@@ -1975,6 +1975,13 @@ static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
 				goto next;
 			if (err)
 				return err;
+			/*
+			 * PSB+ CBR will not have changed but cater for the
+			 * possibility of another CBR change that gets caught up
+			 * in the PSB+.
+			 */
+			if (decoder->cbr != decoder->cbr_seen)
+				return 0;
 			break;
 
 		case INTEL_PT_PIP: