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b12f3ea7c1
Debugfs isn't always available in production builds that try to squeeze every single byte out of the kernel image, but we still need a way to toggle the timestamp and cycle counter registers so that jobs can be profiled for fdinfo's drm engine and cycle calculations. Drop the debugfs knob and replace it with a sysfs file that accomplishes the same functionality, and document its ABI in a separate file. Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Steven Price <steven.price@arm.com> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240306015819.822128-2-adrian.larumbe@collabora.com
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1.7 KiB
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50 lines
1.7 KiB
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.. SPDX-License-Identifier: GPL-2.0+
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=========================
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drm/Panfrost Mali Driver
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=========================
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.. _panfrost-usage-stats:
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Panfrost DRM client usage stats implementation
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==============================================
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The drm/Panfrost driver implements the DRM client usage stats specification as
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documented in :ref:`drm-client-usage-stats`.
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Example of the output showing the implemented key value pairs and entirety of
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the currently possible format options:
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::
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pos: 0
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flags: 02400002
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mnt_id: 27
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ino: 531
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drm-driver: panfrost
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drm-client-id: 14
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drm-engine-fragment: 1846584880 ns
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drm-cycles-fragment: 1424359409
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drm-maxfreq-fragment: 799999987 Hz
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drm-curfreq-fragment: 799999987 Hz
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drm-engine-vertex-tiler: 71932239 ns
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drm-cycles-vertex-tiler: 52617357
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drm-maxfreq-vertex-tiler: 799999987 Hz
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drm-curfreq-vertex-tiler: 799999987 Hz
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drm-total-memory: 290 MiB
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drm-shared-memory: 0 MiB
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drm-active-memory: 226 MiB
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drm-resident-memory: 36496 KiB
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drm-purgeable-memory: 128 KiB
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Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`.
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`drm-curfreq-` values convey the current operating frequency for that engine.
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Users must bear in mind that engine and cycle sampling are disabled by default,
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because of power saving concerns. `fdinfo` users and benchmark applications which
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query the fdinfo file must make sure to toggle the job profiling status of the
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driver by writing into the appropriate sysfs node::
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echo <N> > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/profiling
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Where `N` is either `0` or `1`, depending on the desired enablement status.
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