On Tue, 22 May 2018 05:42:15 +0000 "Ray, Ian (GE Healthcare)" <ian....@ge.com> wrote:
> > On 21 May 2018, at 16.29, Pekka Paalanen <ppaala...@gmail.com> wrote: > > > > Hi, > > > > this series was originally written by me as you can see, and Fabien > > lifted the patches, reviewed, tested and submitted them. If no-one > > objects, I would like to land these on Thursday. > > Reviewed-by: Ian Ray <ian....@ge.com> > > (Nit: patch 3, typo “shadoe”.) Nit fixed and all pushed: 944fae88..e0e39b66 master -> master Thanks, pq > > On Mon, 23 Apr 2018 11:44:55 +0200 > > Fabien Lahoudere <fabien.lahoud...@collabora.com> wrote: > > > >> Optimizes pixman renderer by: > >> - optimizing compositing damage in DRM/pixman > >> > >> Reduce Weston's CPU usage by avoiding unnecessary compositing when > >> updating > >> the shadow buffer in pixman-renderer, under the DRM backend. The test was > >> a > >> proprietary graphical X11 application in demo mode. The effect is a drop > >> of > >> total system CPU usage from 0.41 to 0.33. > >> > >> - optimizing shadow buffer usage > >> > >> The shadow framebuffer is an intermediate buffer where the scene is > >> composited > >> and then copied from the shadow to the actual hardware buffer. This extra > >> step > >> costs memory bandwidth compared to compositing directly into a hardware > >> buffer. > >> > >> Weston's DRM-backend with the Pixman-renderer uses a shadow framebuffer by > >> default. Especially on systems with dedicated VRAM, read-modify-write > >> cycles > >> (a.k.a blending) into the scanout-capable buffer can be very slow. Also > >> the > >> scanout pixel format may not be optimal for compositing. Therefore Weston > >> takes > >> the safe default to always use a shadow framebuffer. > >> > >> However, in our use case, the hardware does not have dedicated VRAM > >> behind a > >> relatively slow bus, and the graphical load has practically no blending. > >> We > >> can reduce Weston's CPU usage quite a lot by not using the shadow > >> frambuffer. > >> > >> We test on proprietary graphical X11 application in demo mode. Using perf > >> we > >> measure that this change improve weston CPU usage by 13% with dual > >> display and > >> 11% with clone mode. > >> > >> Pekka Paalanen (4): > >> pixman,drm: do not composite previous damage > >> pixman: make shadow buffer optional > >> compositor-drm: expose global shadow flag for pixman > >> main: add setting for DRM/pixman shadow framebuffer > >> > >> compositor/main.c | 3 ++ > >> libweston/compositor-drm.c | 30 +++++++------ > >> libweston/compositor-drm.h | 3 ++ > >> libweston/compositor-fbdev.c | 3 +- > >> libweston/compositor-headless.c | 3 +- > >> libweston/compositor-rdp.c | 5 ++- > >> libweston/compositor-wayland.c | 3 +- > >> libweston/compositor-x11.c | 6 ++- > >> libweston/pixman-renderer.c | 99 > >> ++++++++++++++++++++++++++++------------- > >> libweston/pixman-renderer.h | 13 +++++- > >> man/weston-drm.man | 4 ++ > >> 11 files changed, 118 insertions(+), 54 deletions(-) > >> > > > > _______________________________________________ > > wayland-devel mailing list > > wayland-devel@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/wayland-devel >
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