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From: Thomas Zimmermann <tzimmermann@suse.de>
To: daniel@ffwll.ch, deller@gmx.de, javierm@redhat.com,
	geert@linux-m68k.org, sam@ravnborg.org, kraxel@redhat.com
Cc: linux-fbdev@vger.kernel.org,
	Thomas Zimmermann <tzimmermann@suse.de>,
	dri-devel@lists.freedesktop.org
Subject: [PATCH v2 0/5] fbdev: Improve performance of fbdev console
Date: Mon, 21 Feb 2022 20:54:05 +0100	[thread overview]
Message-ID: <20220221195410.9172-1-tzimmermann@suse.de> (raw)

Optimize performance of the fbdev console for the common case of
software-based clearing and image blitting.

The commit descripton of each patch contains resuls os a simple
microbenchmark. I also tested the full patchset's effect on the
console output by printing directory listings (i7-4790, FullHD,
simpledrm, kernel with debugging).

  > time find /usr/share/doc -type f

In the unoptimized case:

  real    0m6.173s
  user    0m0.044s
  sys     0m6.107s

With optimizations applied:

  real    0m4.754s
  user    0m0.044s
  sys     0m4.698s

In the optimized case, printing the directory listing is ~25% faster
than before.

In v2 of the patchset, after implementing Sam's suggestion to update
cfb_imageblit() as well, it turns out that the compiled code in
sys_imageblit() is still significantly slower than the CFB version. A
fix is probably a larger task and would include architecture-specific
changes. A new TODO item suggests to investigate the performance of the
various helpers and format-conversion functions in DRM and fbdev.

v2:
	* improve readability for sys_imageblit() (Gerd, Sam)
	* new TODO item for further optimization

Thomas Zimmermann (5):
  fbdev: Improve performance of sys_fillrect()
  fbdev: Improve performance of sys_imageblit()
  fbdev: Remove trailing whitespaces from cfbimgblt.c
  fbdev: Improve performance of cfb_imageblit()
  drm: Add TODO item for optimizing format helpers

 Documentation/gpu/todo.rst             |  22 +++++
 drivers/video/fbdev/core/cfbimgblt.c   | 107 ++++++++++++++++---------
 drivers/video/fbdev/core/sysfillrect.c |  16 +---
 drivers/video/fbdev/core/sysimgblt.c   |  49 ++++++++---
 4 files changed, 133 insertions(+), 61 deletions(-)

-- 
2.35.1


             reply	other threads:[~2022-02-21 19:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-21 19:54 Thomas Zimmermann [this message]
2022-02-21 19:54 ` [PATCH v2 1/5] fbdev: Improve performance of sys_fillrect() Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 2/5] fbdev: Improve performance of sys_imageblit() Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 3/5] fbdev: Remove trailing whitespaces from cfbimgblt.c Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 4/5] fbdev: Improve performance of cfb_imageblit() Thomas Zimmermann
2022-02-22 13:01   ` Pekka Paalanen
2022-02-22 18:48     ` Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 5/5] drm: Add TODO item for optimizing format helpers Thomas Zimmermann

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