1 1
2 The contents of this directory allow users to 2 The contents of this directory allow users to specify PMU events in their
3 CPUs by their symbolic names rather than raw e 3 CPUs by their symbolic names rather than raw event codes (see example below).
4 4
5 The main program in this directory, is the 'je 5 The main program in this directory, is the 'jevents', which is built and
6 executed _BEFORE_ the perf binary itself is bu 6 executed _BEFORE_ the perf binary itself is built.
7 7
8 The 'jevents' program tries to locate and proc 8 The 'jevents' program tries to locate and process JSON files in the directory
9 tree tools/perf/pmu-events/arch/foo. 9 tree tools/perf/pmu-events/arch/foo.
10 10
11 - Regular files with '.json' extension 11 - Regular files with '.json' extension in the name are assumed to be
12 JSON files, each of which describes 12 JSON files, each of which describes a set of PMU events.
13 13
14 - The CSV file that maps a specific CP 14 - The CSV file that maps a specific CPU to its set of PMU events is to
15 be named 'mapfile.csv' (see below fo 15 be named 'mapfile.csv' (see below for mapfile format).
16 16
17 - Directories are traversed, but all o 17 - Directories are traversed, but all other files are ignored.
18 18
19 - To reduce JSON event duplication per 19 - To reduce JSON event duplication per architecture, platform JSONs may
20 use "ArchStdEvent" keyword to derefe 20 use "ArchStdEvent" keyword to dereference an "Architecture standard
21 events", defined in architecture sta 21 events", defined in architecture standard JSONs.
22 Architecture standard JSONs must be 22 Architecture standard JSONs must be located in the architecture root
23 folder. Matching is based on the "Ev 23 folder. Matching is based on the "EventName" field.
24 24
25 The PMU events supported by a CPU model are ex 25 The PMU events supported by a CPU model are expected to grouped into topics
26 such as Pipelining, Cache, Memory, Floating-po 26 such as Pipelining, Cache, Memory, Floating-point etc. All events for a topic
27 should be placed in a separate JSON file - whe 27 should be placed in a separate JSON file - where the file name identifies
28 the topic. Eg: "Floating-point.json". 28 the topic. Eg: "Floating-point.json".
29 29
30 All the topic JSON files for a CPU model/famil 30 All the topic JSON files for a CPU model/family should be in a separate
31 sub directory. Thus for the Silvermont X86 CPU 31 sub directory. Thus for the Silvermont X86 CPU:
32 32
33 $ ls tools/perf/pmu-events/arch/x86/si 33 $ ls tools/perf/pmu-events/arch/x86/silvermont
34 cache.json memory.json virtual- 34 cache.json memory.json virtual-memory.json
35 frontend.json pipeline.json 35 frontend.json pipeline.json
36 36
37 The JSONs folder for a CPU model/family may be 37 The JSONs folder for a CPU model/family may be placed in the root arch
38 folder, or may be placed in a vendor sub-folde 38 folder, or may be placed in a vendor sub-folder under the arch folder
39 for instances where the arch and vendor are no 39 for instances where the arch and vendor are not the same.
40 40
41 Using the JSON files and the mapfile, 'jevents 41 Using the JSON files and the mapfile, 'jevents' generates the C source file,
42 'pmu-events.c', which encodes the two sets of 42 'pmu-events.c', which encodes the two sets of tables:
43 43
44 - Set of 'PMU events tables' for all k 44 - Set of 'PMU events tables' for all known CPUs in the architecture,
45 (one table like the following, per J 45 (one table like the following, per JSON file; table name 'pme_power8'
46 is derived from JSON file name, 'pow 46 is derived from JSON file name, 'power8.json').
47 47
48 struct pmu_event pme_power8[] 48 struct pmu_event pme_power8[] = {
49 49
50 ... 50 ...
51 51
52 { 52 {
53 .name = "pm_1p 53 .name = "pm_1plus_ppc_cmpl",
54 .event = "even 54 .event = "event=0x100f2",
55 .desc = "1 or 55 .desc = "1 or more ppc insts finished,",
56 }, 56 },
57 57
58 ... 58 ...
59 } 59 }
60 60
61 - A 'mapping table' that maps each CPU 61 - A 'mapping table' that maps each CPU of the architecture, to its
62 'PMU events table' 62 'PMU events table'
63 63
64 struct pmu_events_map pmu_even 64 struct pmu_events_map pmu_events_map[] = {
65 { 65 {
66 .cpuid = "004b0000", 66 .cpuid = "004b0000",
67 .version = "1", 67 .version = "1",
68 .type = "core", 68 .type = "core",
69 .table = pme_power8 69 .table = pme_power8
70 }, 70 },
71 ... 71 ...
72 72
73 }; 73 };
74 74
75 After the 'pmu-events.c' is generated, it is c 75 After the 'pmu-events.c' is generated, it is compiled and the resulting
76 'pmu-events.o' is added to 'libperf.a' which i 76 'pmu-events.o' is added to 'libperf.a' which is then used to build perf.
77 77
78 NOTES: 78 NOTES:
79 1. Several CPUs can support same set o 79 1. Several CPUs can support same set of events and hence use a common
80 JSON file. Hence several entries in 80 JSON file. Hence several entries in the pmu_events_map[] could map
81 to a single 'PMU events table'. 81 to a single 'PMU events table'.
82 82
83 2. The 'pmu-events.h' has an extern de 83 2. The 'pmu-events.h' has an extern declaration for the mapping table
84 and the generated 'pmu-events.c' de 84 and the generated 'pmu-events.c' defines this table.
85 85
86 3. _All_ known CPU tables for architec 86 3. _All_ known CPU tables for architecture are included in the perf
87 binary. 87 binary.
88 88
89 At run time, perf determines the actual CPU it 89 At run time, perf determines the actual CPU it is running on, finds the
90 matching events table and builds aliases for t 90 matching events table and builds aliases for those events. This allows
91 users to specify events by their name: 91 users to specify events by their name:
92 92
93 $ perf stat -e pm_1plus_ppc_cmpl sleep 93 $ perf stat -e pm_1plus_ppc_cmpl sleep 1
94 94
95 where 'pm_1plus_ppc_cmpl' is a Power8 PMU even 95 where 'pm_1plus_ppc_cmpl' is a Power8 PMU event.
96 96
97 However some errors in processing may cause th 97 However some errors in processing may cause the alias build to fail.
98 98
99 Mapfile format 99 Mapfile format
100 =============== 100 ===============
101 101
102 The mapfile enables multiple CPU models to sha 102 The mapfile enables multiple CPU models to share a single set of PMU events.
103 It is required even if such mapping is 1:1. 103 It is required even if such mapping is 1:1.
104 104
105 The mapfile.csv format is expected to be: 105 The mapfile.csv format is expected to be:
106 106
107 Header line 107 Header line
108 CPUID,Version,Dir/path/name,Type 108 CPUID,Version,Dir/path/name,Type
109 109
110 where: 110 where:
111 111
112 Comma: 112 Comma:
113 is the required field delimite 113 is the required field delimiter (i.e other fields cannot
114 have commas within them). 114 have commas within them).
115 115
116 Comments: 116 Comments:
117 Lines in which the first chara 117 Lines in which the first character is either '\n' or '#'
118 are ignored. 118 are ignored.
119 119
120 Header line 120 Header line
121 The header line is the first l 121 The header line is the first line in the file, which is
122 always _IGNORED_. It can be em 122 always _IGNORED_. It can be empty.
123 123
124 CPUID: 124 CPUID:
125 CPUID is an arch-specific char 125 CPUID is an arch-specific char string, that can be used
126 to identify CPU (and associate 126 to identify CPU (and associate it with a set of PMU events
127 it supports). Multiple CPUIDS 127 it supports). Multiple CPUIDS can point to the same
128 File/path/name.json. 128 File/path/name.json.
129 129
130 Example: 130 Example:
131 CPUID == 'GenuineIntel 131 CPUID == 'GenuineIntel-6-2E' (on x86).
132 CPUID == '004b0100' (P 132 CPUID == '004b0100' (PVR value in Powerpc)
133 Version: 133 Version:
134 is the Version of the mapfile. 134 is the Version of the mapfile.
135 135
136 Dir/path/name: 136 Dir/path/name:
137 is the pathname to the directo 137 is the pathname to the directory containing the CPU's JSON
138 files, relative to the directo 138 files, relative to the directory containing the mapfile.csv
139 139
140 Type: 140 Type:
141 indicates whether the events a 141 indicates whether the events are "core" or "uncore" events.
142 142
143 143
144 Eg: 144 Eg:
145 145
146 $ grep silvermont tools/perf/pmu-event 146 $ grep silvermont tools/perf/pmu-events/arch/x86/mapfile.csv
147 GenuineIntel-6-37,v13,silvermont,core 147 GenuineIntel-6-37,v13,silvermont,core
148 GenuineIntel-6-4D,v13,silvermont,core 148 GenuineIntel-6-4D,v13,silvermont,core
149 GenuineIntel-6-4C,v13,silvermont,core 149 GenuineIntel-6-4C,v13,silvermont,core
150 150
151 i.e the three CPU models use the JSON 151 i.e the three CPU models use the JSON files (i.e PMU events) listed
152 in the directory 'tools/perf/pmu-event 152 in the directory 'tools/perf/pmu-events/arch/x86/silvermont'.
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