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1perf-diff(1)
2============
3
4NAME
5----
6perf-diff - Read two perf.data files and display the differential profile
7
8SYNOPSIS
9--------
10[verse]
11'perf diff' [oldfile] [newfile]
12
13DESCRIPTION
14-----------
15This command displays the performance difference amongst two perf.data files
16captured via perf record.
17
18If no parameters are passed it will assume perf.data.old and perf.data.
19
20The differential profile is displayed only for events matching both
21specified perf.data files.
22
23OPTIONS
24-------
25-D::
26--dump-raw-trace::
27 Dump raw trace in ASCII.
28
29-m::
30--modules::
31 Load module symbols. WARNING: use only with -k and LIVE kernel
32
33-d::
34--dsos=::
35 Only consider symbols in these dsos. CSV that understands
36 file://filename entries.
37
38-C::
39--comms=::
40 Only consider symbols in these comms. CSV that understands
41 file://filename entries.
42
43-S::
44--symbols=::
45 Only consider these symbols. CSV that understands
46 file://filename entries.
47
48-s::
49--sort=::
50 Sort by key(s): pid, comm, dso, symbol.
51
52-t::
53--field-separator=::
54
55 Use a special separator character and don't pad with spaces, replacing
56 all occurrences of this separator in symbol names (and other output)
57 with a '.' character, that thus it's the only non valid separator.
58
59-v::
60--verbose::
61 Be verbose, for instance, show the raw counts in addition to the
62 diff.
63
64-f::
65--force::
66 Don't complain, do it.
67
68--symfs=<directory>::
69 Look for files with symbols relative to this directory.
70
71-b::
72--baseline-only::
73 Show only items with match in baseline.
74
75-c::
76--compute::
77 Differential computation selection - delta,ratio,wdiff (default is delta).
78 If '+' is specified as a first character, the output is sorted based
79 on the computation results.
80 See COMPARISON METHODS section for more info.
81
82-p::
83--period::
84 Show period values for both compared hist entries.
85
86-F::
87--formula::
88 Show formula for given computation.
89
90COMPARISON METHODS
91------------------
92delta
93~~~~~
94If specified the 'Delta' column is displayed with value 'd' computed as:
95
96 d = A->period_percent - B->period_percent
97
98with:
99 - A/B being matching hist entry from first/second file specified
100 (or perf.data/perf.data.old) respectively.
101
102 - period_percent being the % of the hist entry period value within
103 single data file
104
105ratio
106~~~~~
107If specified the 'Ratio' column is displayed with value 'r' computed as:
108
109 r = A->period / B->period
110
111with:
112 - A/B being matching hist entry from first/second file specified
113 (or perf.data/perf.data.old) respectively.
114
115 - period being the hist entry period value
116
117wdiff
118~~~~~
119If specified the 'Weighted diff' column is displayed with value 'd' computed as:
120
121 d = B->period * WEIGHT-A - A->period * WEIGHT-B
122
123 - A/B being matching hist entry from first/second file specified
124 (or perf.data/perf.data.old) respectively.
125
126 - period being the hist entry period value
127
128 - WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option
129 behind ':' separator like '-c wdiff:1,2'.
130
131SEE ALSO
132--------
133linkperf:perf-record[1]