From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- Documentation/gpu/panfrost.rst | 49 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 Documentation/gpu/panfrost.rst (limited to 'Documentation/gpu/panfrost.rst') diff --git a/Documentation/gpu/panfrost.rst b/Documentation/gpu/panfrost.rst new file mode 100644 index 000000000..51ba375fd --- /dev/null +++ b/Documentation/gpu/panfrost.rst @@ -0,0 +1,49 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +========================= + drm/Panfrost Mali Driver +========================= + +.. _panfrost-usage-stats: + +Panfrost DRM client usage stats implementation +============================================== + +The drm/Panfrost driver implements the DRM client usage stats specification as +documented in :ref:`drm-client-usage-stats`. + +Example of the output showing the implemented key value pairs and entirety of +the currently possible format options: + +:: + pos: 0 + flags: 02400002 + mnt_id: 27 + ino: 531 + drm-driver: panfrost + drm-client-id: 14 + drm-engine-fragment: 1846584880 ns + drm-cycles-fragment: 1424359409 + drm-maxfreq-fragment: 799999987 Hz + drm-curfreq-fragment: 799999987 Hz + drm-engine-vertex-tiler: 71932239 ns + drm-cycles-vertex-tiler: 52617357 + drm-maxfreq-vertex-tiler: 799999987 Hz + drm-curfreq-vertex-tiler: 799999987 Hz + drm-total-memory: 290 MiB + drm-shared-memory: 0 MiB + drm-active-memory: 226 MiB + drm-resident-memory: 36496 KiB + drm-purgeable-memory: 128 KiB + +Possible `drm-engine-` key names are: `fragment`, and `vertex-tiler`. +`drm-curfreq-` values convey the current operating frequency for that engine. + +Users must bear in mind that engine and cycle sampling are disabled by default, +because of power saving concerns. `fdinfo` users and benchmark applications which +query the fdinfo file must make sure to toggle the job profiling status of the +driver by writing into the appropriate sysfs node:: + + echo > /sys/bus/platform/drivers/panfrost/[a-f0-9]*.gpu/profiling + +Where `N` is either `0` or `1`, depending on the desired enablement status. -- cgit v1.3.1