+
+ The 'e' option may be followed by flags which affect what errors will or
+ will not be reported. Each flag must be preceded by either '+' or '-'.
+ The flags are:
+ o overflow
+ l trace data lost
+
+ If supported, the 'd' option may be followed by flags which affect what
+ debug messages will or will not be logged. Each flag must be preceded
+ by either '+' or '-'. The flags are:
+ a all perf events
+
+ If supported, the 'q' option may be repeated to increase the effect.