[PATCH v3 5/5] drm: Add TODO item for optimizing format helpers
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: 2022-02-23 19:38:19
Also in:
dri-devel
Subsystem:
documentation, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
Jonathan Corbet, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
Add a TODO item for optimizing blitting and format-conversion helpers in DRM and fbdev. There's always demand for faster graphics output. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> --- Documentation/gpu/todo.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 7bf7f2111696..7f113c6a02dd 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst@@ -241,6 +241,28 @@ Contact: Thomas Zimmermann <tzimmermann@suse.de>, Daniel Vetter Level: Advanced +Benchmark and optimize blitting and format-conversion function +-------------------------------------------------------------- + +Drawing to dispay memory quickly is crucial for many applications' +performance. + +On at least x86-64, sys_imageblit() is significantly slower than +cfb_imageblit(), even though both use the same blitting algorithm and +the latter is written for I/O memory. It turns out that cfb_imageblit() +uses movl instructions, while sys_imageblit apparently does not. This +seems to be a problem with gcc's optimizer. DRM's format-conversion +heleprs might be subject to similar issues. + +Benchmark and optimize fbdev's sys_() helpers and DRM's format-conversion +helpers. In cases that can be further optimized, maybe implement a different +algorithm, For micro-optimizations, use movl/movq instructions explicitly. +That might possibly require architecture specific helpers (e.g., storel() +storeq()). + +Contact: Thomas Zimmermann <tzimmermann@suse.de> + +Level: Intermediate drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup -----------------------------------------------------------------
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2.35.1