Re: [PATCH v3 5/5] drm: Add TODO item for optimizing format helpers
On 2/23/22 20:38, Thomas Zimmermann wrote: > 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 > --- After fixing the typos mentioned by Sam: Reviewed-by: Javier Martinez Canillas Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat
Re: [PATCH v3 5/5] drm: Add TODO item for optimizing format helpers
On Wed, Feb 23, 2022 at 08:38:04PM +0100, Thomas Zimmermann wrote: > 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 > --- > 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 , Daniel > Vetter > > Level: Advanced > > +Benchmark and optimize blitting and format-conversion function > +-- > + > +Drawing to dispay memory quickly is crucial for many applications' display > +performance. > + > +On at least x86-64, sys_imageblit() is significantly slower than On, at least x86-64, ... To me the extra comma makes sense, but grammar is not my strong side. > +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. helpers > + > +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. algorithm. (period, not comma) > +That might possibly require architecture specific helpers (e.g., storel() > +storeq()). > + > +Contact: Thomas Zimmermann > + > +Level: Intermediate With the small fixes above: Acked-by: Sam Ravnborg Another option would be to re-implement imageblit() to be drm specific. Maybe we can then throw out some legacy code and optimize only for the drm use. And then maybe only a small part of the code would differ if this is I/O memory or direct accessible memory. Sam
[PATCH v3 5/5] drm: Add TODO item for optimizing format helpers
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 --- 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 , 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 + +Level: Intermediate drm_framebuffer_funcs and drm_mode_config_funcs.fb_create cleanup - -- 2.35.1
