1		i	synthesize instructions events
2		b	synthesize branches events (branch misses for Arm SPE)
3		c	synthesize branches events (calls only)
4		r	synthesize branches events (returns only)
5		x	synthesize transactions events
6		w	synthesize ptwrite events
7		p	synthesize power events (incl. PSB events for Intel PT)
8		o	synthesize other events recorded due to the use
9			of aux-output (refer to perf record)
10		I	synthesize interrupt or similar (asynchronous) events
11			(e.g. Intel PT Event Trace)
12		e	synthesize error events
13		d	create a debug log
14		f	synthesize first level cache events
15		m	synthesize last level cache events
16		M	synthesize memory events
17		t	synthesize TLB events
18		a	synthesize remote access events
19		g	synthesize a call chain (use with i or x)
20		G	synthesize a call chain on existing event records
21		l	synthesize last branch entries (use with i or x)
22		L	synthesize last branch entries on existing event records
23		s       skip initial number of events
24		q	quicker (less detailed) decoding
25		A	approximate IPC
26		Z	prefer to ignore timestamps (so-called "timeless" decoding)
27
28	The default is all events i.e. the same as --itrace=ibxwpe,
29	except for perf script where it is --itrace=ce
30
31	In addition, the period (default 100000, except for perf script where it is 1)
32	for instructions events can be specified in units of:
33
34		i	instructions
35		t	ticks
36		ms	milliseconds
37		us	microseconds
38		ns	nanoseconds (default)
39
40	Also the call chain size (default 16, max. 1024) for instructions or
41	transactions events can be specified.
42
43	Also the number of last branch entries (default 64, max. 1024) for
44	instructions or transactions events can be specified.
45
46	Similar to options g and l, size may also be specified for options G and L.
47	On x86, note that G and L work poorly when data has been recorded with
48	large PEBS. Refer linkperf:perf-intel-pt[1] man page for details.
49
50	It is also possible to skip events generated (instructions, branches, transactions,
51	ptwrite, power) at the beginning. This is useful to ignore initialization code.
52
53	--itrace=i0nss1000000
54
55	skips the first million instructions.
56
57	The 'e' option may be followed by flags which affect what errors will or
58	will not be reported. Each flag must be preceded by either '+' or '-'.
59	The flags are:
60		o	overflow
61		l	trace data lost
62
63	If supported, the 'd' option may be followed by flags which affect what
64	debug messages will or will not be logged. Each flag must be preceded
65	by either '+' or '-'. The flags are:
66		a	all perf events
67		o	output to stdout
68
69	If supported, the 'q' option may be repeated to increase the effect.
70