Re: [PATCH v2 0/9] drm/vkms: Reimplement line-per-line pixel conversion for plane reading

[Maira Canal]

Hi Louis,

On 2/23/24 08:37, Louis Chauvet wrote:
> This patchset is the second version of [1]. It is almost a complete
> rewrite to use a line-by-line algorithm for the composition.
> It can be divided in three parts:
> - PATCH 1 to 4: no functional change is intended, only some formatting and
> documenting
> (PATCH 2 is taken from [2])
> - PATCH 5: main patch for this series, it reintroduce the
> line-by-line algorithm
> - PATCH 6 to 9: taken from Arthur's series [2], with sometimes adaptation
> to use the pixel-by-pixel algorithm.
>
> The PATCH 5 aims to restore the line-by-line pixel reading algorithm. It
> was introduced in 8ba1648567e2 ("drm: vkms: Refactor the plane composer to
> accept new formats") but removed in 8ba1648567e2 ("drm: vkms: Refactor the
> plane composer to accept new formats") in a over-simplification effort.
> At this time, nobody noticed the performance impact of this commit. After
> the first iteration of my series, poeple notice performance impact, and it
> was the case. Pekka suggested to reimplement the line-by-line algorithm.
>
> Expiriments on my side shown great improvement for the line-by-line
> algorithm, and the performances are the same as the original line-by-line
> algorithm. I targeted my effort to make the code working for all the
> rotations and translations. The usage of helpers from drm_rect_* avoid
> reimplementing existing logic.
>
> The only "complex" part remaining is the clipping of the coordinate to
> avoid reading/writing outside of src/dst. Thus I added a lot of comments
> to help when someone will want to add some features (framebuffer resizing
> for example).
>
> The YUV part is not mandatory for this series, but as my first effort was
> to help the integration of YUV, I decided to rebase Arthur's series on
> mine to help. I took [3], [4], [5] and [6] and adapted them to use the
> line-by-line reading. If I did something wrong here, please let me
> know.
>
> My series was mainly tested with:
> - kms_plane (for color conversions)
> - kms_rotation_crc (for rotations of planes)
> - kms_cursor_crc (for translations)
> The benchmark used to measure the improvment was done with:
> - kms_fb_stress
>
> [1]: https://lore.kernel.org/r/20240201-yuv-v1-0-3ca376f27632@xxxxxxxxxxx
> [2]: https://lore.kernel.org/all/20240110-vkms-yuv-v2-0-952fcaa5a193@xxxxxxxxxx/
> [3]: https://lore.kernel.org/all/20240110-vkms-yuv-v2-3-952fcaa5a193@xxxxxxxxxx/
> [4]: https://lore.kernel.org/all/20240110-vkms-yuv-v2-5-952fcaa5a193@xxxxxxxxxx/
> [5]: https://lore.kernel.org/all/20240110-vkms-yuv-v2-6-952fcaa5a193@xxxxxxxxxx/
> [6]: https://lore.kernel.org/all/20240110-vkms-yuv-v2-7-952fcaa5a193@xxxxxxxxxx/
>
> To: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx>
> To: Melissa Wen <melissa.srw@xxxxxxxxx>
> To: Maíra Canal <mairacanal@xxxxxxxxxx>
> To: Haneen Mohammed <hamohammed.sa@xxxxxxxxx>
> To: Daniel Vetter <daniel@xxxxxxxx>
> To: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> To: Maxime Ripard <mripard@xxxxxxxxxx>
> To: Thomas Zimmermann <tzimmermann@xxxxxxx>
> To: David Airlie <airlied@xxxxxxxxx>
> To: arthurgrillo@xxxxxxxxxx
> To: Jonathan Corbet <corbet@xxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: jeremie.dautheribes@xxxxxxxxxxx
> Cc: miquel.raynal@xxxxxxxxxxx
> Cc: thomas.petazzoni@xxxxxxxxxxx
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
>
> Note: after my changes, those tests seems to pass, so [7] may need
> updating (I did not check, it was maybe already the case):
> - kms_cursor_legacy@flip-vs-cursor-atomic
> - kms_pipe_crc_basic@nonblocking-crc
> - kms_pipe_crc_basic@nonblocking-crc-frame-sequence
> - kms_writeback@writeback-pixel-formats
> - kms_writeback@writeback-invalid-parameters
> - kms_flip@flip-vs-absolute-wf_vblank-interruptible
> And those tests pass, I did not investigate why the runners fails:
> - kms_flip@flip-vs-expired-vblank-interruptible
> - kms_flip@flip-vs-expired-vblank
> - kms_flip@plain-flip-fb-recreate
> - kms_flip@plain-flip-fb-recreate-interruptible
> - kms_flip@plain-flip-ts-check-interruptible
> - kms_cursor_legacy@cursorA-vs-flipA-toggle
> - kms_pipe_crc_basic@nonblocking-crc
> - kms_prop_blob@invalid-get-prop
> - kms_flip@flip-vs-absolute-wf_vblank-interruptible
> - kms_invalid_mode@zero-hdisplay
> - kms_invalid_mode@bad-vtotal
> - kms_cursor_crc.* (everything is SUCCEED or SKIP, but no fails)

This is great news! Could you just adjust the series fixing the
compiling errors?

Best Regards,
- Maíra

> [7]: https://lore.kernel.org/all/20240201065346.801038-1-vignesh.raman@xxxxxxxxxxxxx/
>
> Changes in v2:
> - Rebased the series on top of drm-misc/drm-misc-net
> - Extract the typedef for pixel_read/pixel_write
> - Introduce the line-by-line algorithm per pixel format
> - Add some documentation for existing and new code
> - Port the series [1] to use line-by-line algorithm
> - Link to v1: https://lore.kernel.org/r/20240201-yuv-v1-0-3ca376f27632@xxxxxxxxxxx
>
> ---
> Arthur Grillo (5):
>        drm/vkms: Use drm_frame directly
>        drm/vkms: Add YUV support
>        drm/vkms: Add range and encoding properties to pixel_read function
>        drm/vkms: Drop YUV formats TODO
>        drm/vkms: Create KUnit tests for YUV conversions
>
> Louis Chauvet (4):
>        drm/vkms: Code formatting
>        drm/vkms: write/update the documentation for pixel conversion and pixel write functions
>        drm/vkms: Add typedef and documentation for pixel_read and pixel_write functions
>        drm/vkms: Re-introduce line-per-line composition algorithm
>
>   Documentation/gpu/vkms.rst                    |   3 +-
>   drivers/gpu/drm/vkms/Makefile                 |   1 +
>   drivers/gpu/drm/vkms/tests/.kunitconfig       |   4 +
>   drivers/gpu/drm/vkms/tests/Makefile           |   3 +
>   drivers/gpu/drm/vkms/tests/vkms_format_test.c | 155 +++++++
>   drivers/gpu/drm/vkms/vkms_composer.c          | 233 ++++++++---
>   drivers/gpu/drm/vkms/vkms_crtc.c              |   6 +-
>   drivers/gpu/drm/vkms/vkms_drv.c               |   3 +-
>   drivers/gpu/drm/vkms/vkms_drv.h               |  56 ++-
>   drivers/gpu/drm/vkms/vkms_formats.c           | 565 +++++++++++++++++++++-----
>   drivers/gpu/drm/vkms/vkms_formats.h           |  13 +-
>   drivers/gpu/drm/vkms/vkms_plane.c             |  50 ++-
>   drivers/gpu/drm/vkms/vkms_writeback.c         |  14 +-
>   13 files changed, 916 insertions(+), 190 deletions(-)
> ---
> base-commit: aa1267e673fe5307cf00d02add4017d2878598b6
> change-id: 20240201-yuv-1337d90d9576
>
> Best regards,