1 .. _drm-client-usage-stats: 1 .. _drm-client-usage-stats:
2 2
3 ====================== 3 ======================
4 DRM client usage stats 4 DRM client usage stats
5 ====================== 5 ======================
6 6
7 DRM drivers can choose to export partly standa 7 DRM drivers can choose to export partly standardised text output via the
8 `fops->show_fdinfo()` as part of the driver sp 8 `fops->show_fdinfo()` as part of the driver specific file operations registered
9 in the `struct drm_driver` object registered w 9 in the `struct drm_driver` object registered with the DRM core.
10 10
11 One purpose of this output is to enable writin !! 11 One purpose of this output is to enable writing as generic as practicaly
12 feasible `top(1)` like userspace monitoring to 12 feasible `top(1)` like userspace monitoring tools.
13 13
14 Given the differences between various DRM driv 14 Given the differences between various DRM drivers the specification of the
15 output is split between common and driver spec 15 output is split between common and driver specific parts. Having said that,
16 wherever possible effort should still be made 16 wherever possible effort should still be made to standardise as much as
17 possible. 17 possible.
18 18
19 File format specification 19 File format specification
20 ========================= 20 =========================
21 21
22 - File shall contain one key value pair per on 22 - File shall contain one key value pair per one line of text.
23 - Colon character (`:`) must be used to delimi 23 - Colon character (`:`) must be used to delimit keys and values.
24 - All keys shall be prefixed with `drm-`. 24 - All keys shall be prefixed with `drm-`.
25 - Whitespace between the delimiter and first n 25 - Whitespace between the delimiter and first non-whitespace character shall be
26 ignored when parsing. 26 ignored when parsing.
27 - Keys are not allowed to contain whitespace c !! 27 - Neither keys or values are allowed to contain whitespace characters.
28 - Numerical key value pairs can end with optio 28 - Numerical key value pairs can end with optional unit string.
29 - Data type of the value is fixed as defined i 29 - Data type of the value is fixed as defined in the specification.
30 30
31 Key types 31 Key types
32 --------- 32 ---------
33 33
34 1. Mandatory, fully standardised. 34 1. Mandatory, fully standardised.
35 2. Optional, fully standardised. 35 2. Optional, fully standardised.
36 3. Driver specific. 36 3. Driver specific.
37 37
38 Data types 38 Data types
39 ---------- 39 ----------
40 40
41 - <uint> - Unsigned integer without defining t 41 - <uint> - Unsigned integer without defining the maximum value.
42 - <keystr> - String excluding any above define !! 42 - <str> - String excluding any above defined reserved characters or whitespace.
43 - <valstr> - String. <<
44 43
45 Mandatory fully standardised keys 44 Mandatory fully standardised keys
46 --------------------------------- 45 ---------------------------------
47 46
48 - drm-driver: <valstr> !! 47 - drm-driver: <str>
49 48
50 String shall contain the name this driver regi 49 String shall contain the name this driver registered as via the respective
51 `struct drm_driver` data structure. 50 `struct drm_driver` data structure.
52 51
53 Optional fully standardised keys 52 Optional fully standardised keys
54 -------------------------------- 53 --------------------------------
55 54
56 Identification <<
57 ^^^^^^^^^^^^^^ <<
58 <<
59 - drm-pdev: <aaaa:bb.cc.d> 55 - drm-pdev: <aaaa:bb.cc.d>
60 56
61 For PCI devices this should contain the PCI sl 57 For PCI devices this should contain the PCI slot address of the device in
62 question. 58 question.
63 59
64 - drm-client-id: <uint> 60 - drm-client-id: <uint>
65 61
66 Unique value relating to the open DRM file des 62 Unique value relating to the open DRM file descriptor used to distinguish
67 duplicated and shared file descriptors. Concep 63 duplicated and shared file descriptors. Conceptually the value should map 1:1
68 to the in kernel representation of `struct drm 64 to the in kernel representation of `struct drm_file` instances.
69 65
70 Uniqueness of the value shall be either global 66 Uniqueness of the value shall be either globally unique, or unique within the
71 scope of each device, in which case `drm-pdev` 67 scope of each device, in which case `drm-pdev` shall be present as well.
72 68
73 Userspace should make sure to not double accou 69 Userspace should make sure to not double account any usage statistics by using
74 the above described criteria in order to assoc 70 the above described criteria in order to associate data to individual clients.
75 71
76 Utilization !! 72 - drm-engine-<str>: <uint> ns
77 ^^^^^^^^^^^ <<
78 <<
79 - drm-engine-<keystr>: <uint> ns <<
80 73
81 GPUs usually contain multiple execution engine 74 GPUs usually contain multiple execution engines. Each shall be given a stable
82 and unique name (keystr), with possible values !! 75 and unique name (str), with possible values documented in the driver specific
83 documentation. 76 documentation.
84 77
85 Value shall be in specified time units which t 78 Value shall be in specified time units which the respective GPU engine spent
86 busy executing workloads belonging to this cli 79 busy executing workloads belonging to this client.
87 80
88 Values are not required to be constantly monot 81 Values are not required to be constantly monotonic if it makes the driver
89 implementation easier, but are required to cat 82 implementation easier, but are required to catch up with the previously reported
90 larger value within a reasonable period. Upon 83 larger value within a reasonable period. Upon observing a value lower than what
91 was previously read, userspace is expected to 84 was previously read, userspace is expected to stay with that larger previous
92 value until a monotonic update is seen. 85 value until a monotonic update is seen.
93 86
94 - drm-engine-capacity-<keystr>: <uint> !! 87 - drm-engine-capacity-<str>: <uint>
95 88
96 Engine identifier string must be the same as t 89 Engine identifier string must be the same as the one specified in the
97 drm-engine-<keystr> tag and shall contain a gr !! 90 drm-engine-<str> tag and shall contain a greater than zero number in case the
98 exported engine corresponds to a group of iden 91 exported engine corresponds to a group of identical hardware engines.
99 92
100 In the absence of this tag parser shall assume 93 In the absence of this tag parser shall assume capacity of one. Zero capacity
101 is not allowed. 94 is not allowed.
102 95
103 - drm-cycles-<keystr>: <uint> !! 96 - drm-memory-<str>: <uint> [KiB|MiB]
104 <<
105 Engine identifier string must be the same as t <<
106 drm-engine-<keystr> tag and shall contain the <<
107 engine. <<
108 <<
109 Values are not required to be constantly monot <<
110 implementation easier, but are required to cat <<
111 larger value within a reasonable period. Upon <<
112 was previously read, userspace is expected to <<
113 value until a monotonic update is seen. <<
114 <<
115 - drm-total-cycles-<keystr>: <uint> <<
116 <<
117 Engine identifier string must be the same as t <<
118 drm-cycles-<keystr> tag and shall contain the <<
119 engine. <<
120 <<
121 This is a timestamp in GPU unspecified unit th <<
122 of drm-cycles-<keystr>. For drivers that imple <<
123 utilization can be calculated entirely on the <<
124 considering the CPU sleep time between 2 sampl <<
125 <<
126 A driver may implement either this key or drm- <<
127 <<
128 - drm-maxfreq-<keystr>: <uint> [Hz|MHz|KHz] <<
129 <<
130 Engine identifier string must be the same as t <<
131 drm-engine-<keystr> tag and shall contain the <<
132 engine. Taken together with drm-cycles-<keyst <<
133 percentage utilization of the engine, whereas <<
134 time active without considering what frequency <<
135 percentage of its maximum frequency. <<
136 <<
137 A driver may implement either this key or drm- <<
138 both. <<
139 <<
140 Memory <<
141 ^^^^^^ <<
142 <<
143 - drm-memory-<region>: <uint> [KiB|MiB] <<
144 97
145 Each possible memory type which can be used to 98 Each possible memory type which can be used to store buffer objects by the
146 GPU in question shall be given a stable and un 99 GPU in question shall be given a stable and unique name to be returned as the
147 string here. The name "memory" is reserved to !! 100 string here.
148 101
149 Value shall reflect the amount of storage curr 102 Value shall reflect the amount of storage currently consumed by the buffer
150 objects belong to this client, in the respecti !! 103 object belong to this client, in the respective memory region.
151 104
152 Default unit shall be bytes with optional unit 105 Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB'
153 indicating kibi- or mebi-bytes. 106 indicating kibi- or mebi-bytes.
154 107
155 - drm-shared-<region>: <uint> [KiB|MiB] !! 108 - drm-cycles-<str> <uint>
156 <<
157 The total size of buffers that are shared with <<
158 than a single handle). <<
159 <<
160 - drm-total-<region>: <uint> [KiB|MiB] <<
161 <<
162 The total size of buffers that including share <<
163 <<
164 - drm-resident-<region>: <uint> [KiB|MiB] <<
165 <<
166 The total size of buffers that are resident in <<
167 <<
168 - drm-purgeable-<region>: <uint> [KiB|MiB] <<
169 109
170 The total size of buffers that are purgeable. !! 110 Engine identifier string must be the same as the one specified in the
171 !! 111 drm-engine-<str> tag and shall contain the number of busy cycles for the given
172 - drm-active-<region>: <uint> [KiB|MiB] !! 112 engine.
173 113
174 The total size of buffers that are active on o !! 114 Values are not required to be constantly monotonic if it makes the driver
>> 115 implementation easier, but are required to catch up with the previously reported
>> 116 larger value within a reasonable period. Upon observing a value lower than what
>> 117 was previously read, userspace is expected to stay with that larger previous
>> 118 value until a monotonic update is seen.
175 119
176 Implementation Details !! 120 - drm-maxfreq-<str> <uint> [Hz|MHz|KHz]
177 ====================== <<
178 121
179 Drivers should use drm_show_fdinfo() in their !! 122 Engine identifier string must be the same as the one specified in the
180 implement &drm_driver.show_fdinfo if they wish !! 123 drm-engine-<str> tag and shall contain the maximum frequency for the given
181 are not provided by drm_show_fdinfo(). But ev !! 124 engine. Taken together with drm-cycles-<str>, this can be used to calculate
182 be documented above and where possible, aligne !! 125 percentage utilization of the engine, whereas drm-engine-<str> only reflects
>> 126 time active without considering what frequency the engine is operating as a
>> 127 percentage of it's maximum frequency.
183 128
>> 129 ===============================
184 Driver specific implementations 130 Driver specific implementations
185 ------------------------------- !! 131 ===============================
186 132
187 * :ref:`i915-usage-stats` !! 133 :ref:`i915-usage-stats`
188 * :ref:`panfrost-usage-stats` <<
189 * :ref:`xe-usage-stats` <<
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.