1		i	synthesize instructions events
2		y	synthesize cycles events
3		b	synthesize branches events (branch misses for Arm SPE)
4		c	synthesize branches events (calls only)
5		r	synthesize branches events (returns only)
6		x	synthesize transactions events
7		w	synthesize ptwrite events
8		p	synthesize power events (incl. PSB events for Intel PT)
9		o	synthesize other events recorded due to the use
10			of aux-output (refer to perf record)
11		I	synthesize interrupt or similar (asynchronous) events
12			(e.g. Intel PT Event Trace)
13		e	synthesize error events
14		d	create a debug log
15		f	synthesize first level cache events
16		m	synthesize last level cache events
17		M	synthesize memory events
18		t	synthesize TLB events
19		a	synthesize remote access events
20		g	synthesize a call chain (use with i or x)
21		G	synthesize a call chain on existing event records
22		l	synthesize last branch entries (use with i or x)
23		L	synthesize last branch entries on existing event records
24		s       skip initial number of events
25		q	quicker (less detailed) decoding
26		A	approximate IPC
27		Z	prefer to ignore timestamps (so-called "timeless" decoding)
28
29	The default is all events i.e. the same as --itrace=iybxwpe,
30	except for perf script where it is --itrace=ce
31
32	In addition, the period (default 100000, except for perf script where it is 1)
33	for instructions events can be specified in units of:
34
35		i	instructions
36		t	ticks
37		ms	milliseconds
38		us	microseconds
39		ns	nanoseconds (default)
40
41	Also the call chain size (default 16, max. 1024) for instructions or
42	transactions events can be specified.
43
44	Also the number of last branch entries (default 64, max. 1024) for
45	instructions or transactions events can be specified.
46
47	Similar to options g and l, size may also be specified for options G and L.
48	On x86, note that G and L work poorly when data has been recorded with
49	large PEBS. Refer linkperf:perf-intel-pt[1] man page for details.
50
51	It is also possible to skip events generated (instructions, branches, transactions,
52	ptwrite, power) at the beginning. This is useful to ignore initialization code.
53
54	--itrace=i0nss1000000
55
56	skips the first million instructions.
57
58	The 'e' option may be followed by flags which affect what errors will or
59	will not be reported. Each flag must be preceded by either '+' or '-'.
60	The flags are:
61		o	overflow
62		l	trace data lost
63
64	If supported, the 'd' option may be followed by flags which affect what
65	debug messages will or will not be logged. Each flag must be preceded
66	by either '+' or '-'. The flags are:
67		a	all perf events
68		e	output only on errors (size configurable - see linkperf:perf-config[1])
69		o	output to stdout
70
71	If supported, the 'q' option may be repeated to increase the effect.
72