Based on kernel version 6.11
. Page generated on 2024-09-24 08:21 EST
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | .. _drm-client-usage-stats: ====================== DRM client usage stats ====================== DRM drivers can choose to export partly standardised text output via the `fops->show_fdinfo()` as part of the driver specific file operations registered in the `struct drm_driver` object registered with the DRM core. One purpose of this output is to enable writing as generic as practically feasible `top(1)` like userspace monitoring tools. Given the differences between various DRM drivers the specification of the output is split between common and driver specific parts. Having said that, wherever possible effort should still be made to standardise as much as possible. File format specification ========================= - File shall contain one key value pair per one line of text. - Colon character (`:`) must be used to delimit keys and values. - All keys shall be prefixed with `drm-`. - Whitespace between the delimiter and first non-whitespace character shall be ignored when parsing. - Keys are not allowed to contain whitespace characters. - Numerical key value pairs can end with optional unit string. - Data type of the value is fixed as defined in the specification. Key types --------- 1. Mandatory, fully standardised. 2. Optional, fully standardised. 3. Driver specific. Data types ---------- - <uint> - Unsigned integer without defining the maximum value. - <keystr> - String excluding any above defined reserved characters or whitespace. - <valstr> - String. Mandatory fully standardised keys --------------------------------- - drm-driver: <valstr> String shall contain the name this driver registered as via the respective `struct drm_driver` data structure. Optional fully standardised keys -------------------------------- Identification ^^^^^^^^^^^^^^ - drm-pdev: <aaaa:bb.cc.d> For PCI devices this should contain the PCI slot address of the device in question. - drm-client-id: <uint> Unique value relating to the open DRM file descriptor used to distinguish duplicated and shared file descriptors. Conceptually the value should map 1:1 to the in kernel representation of `struct drm_file` instances. Uniqueness of the value shall be either globally unique, or unique within the scope of each device, in which case `drm-pdev` shall be present as well. Userspace should make sure to not double account any usage statistics by using the above described criteria in order to associate data to individual clients. Utilization ^^^^^^^^^^^ - drm-engine-<keystr>: <uint> ns GPUs usually contain multiple execution engines. Each shall be given a stable and unique name (keystr), with possible values documented in the driver specific documentation. Value shall be in specified time units which the respective GPU engine spent busy executing workloads belonging to this client. Values are not required to be constantly monotonic if it makes the driver implementation easier, but are required to catch up with the previously reported larger value within a reasonable period. Upon observing a value lower than what was previously read, userspace is expected to stay with that larger previous value until a monotonic update is seen. - drm-engine-capacity-<keystr>: <uint> Engine identifier string must be the same as the one specified in the drm-engine-<keystr> tag and shall contain a greater than zero number in case the exported engine corresponds to a group of identical hardware engines. In the absence of this tag parser shall assume capacity of one. Zero capacity is not allowed. - drm-cycles-<keystr>: <uint> Engine identifier string must be the same as the one specified in the drm-engine-<keystr> tag and shall contain the number of busy cycles for the given engine. Values are not required to be constantly monotonic if it makes the driver implementation easier, but are required to catch up with the previously reported larger value within a reasonable period. Upon observing a value lower than what was previously read, userspace is expected to stay with that larger previous value until a monotonic update is seen. - drm-total-cycles-<keystr>: <uint> Engine identifier string must be the same as the one specified in the drm-cycles-<keystr> tag and shall contain the total number cycles for the given engine. This is a timestamp in GPU unspecified unit that matches the update rate of drm-cycles-<keystr>. For drivers that implement this interface, the engine utilization can be calculated entirely on the GPU clock domain, without considering the CPU sleep time between 2 samples. A driver may implement either this key or drm-maxfreq-<keystr>, but not both. - drm-maxfreq-<keystr>: <uint> [Hz|MHz|KHz] Engine identifier string must be the same as the one specified in the drm-engine-<keystr> tag and shall contain the maximum frequency for the given engine. Taken together with drm-cycles-<keystr>, this can be used to calculate percentage utilization of the engine, whereas drm-engine-<keystr> only reflects time active without considering what frequency the engine is operating as a percentage of its maximum frequency. A driver may implement either this key or drm-total-cycles-<keystr>, but not both. Memory ^^^^^^ - drm-memory-<region>: <uint> [KiB|MiB] Each possible memory type which can be used to store buffer objects by the GPU in question shall be given a stable and unique name to be returned as the string here. The name "memory" is reserved to refer to normal system memory. Value shall reflect the amount of storage currently consumed by the buffer objects belong to this client, in the respective memory region. Default unit shall be bytes with optional unit specifiers of 'KiB' or 'MiB' indicating kibi- or mebi-bytes. - drm-shared-<region>: <uint> [KiB|MiB] The total size of buffers that are shared with another file (e.g., have more than a single handle). - drm-total-<region>: <uint> [KiB|MiB] The total size of buffers that including shared and private memory. - drm-resident-<region>: <uint> [KiB|MiB] The total size of buffers that are resident in the specified region. - drm-purgeable-<region>: <uint> [KiB|MiB] The total size of buffers that are purgeable. - drm-active-<region>: <uint> [KiB|MiB] The total size of buffers that are active on one or more engines. Implementation Details ====================== Drivers should use drm_show_fdinfo() in their `struct file_operations`, and implement &drm_driver.show_fdinfo if they wish to provide any stats which are not provided by drm_show_fdinfo(). But even driver specific stats should be documented above and where possible, aligned with other drivers. Driver specific implementations ------------------------------- * :ref:`i915-usage-stats` * :ref:`panfrost-usage-stats` * :ref:`xe-usage-stats` |