On 5 February 2013 22:40, Kenneth Graunke <kenn...@whitecape.org> wrote:
> The BLT engine has many limitations. Currently, it can only blit > X-tiled buffers (since we don't have a kernel API to whack the BLT > tiling mode register), which means all depth/stencil operations get > punted to meta code, which can be very CPU-intensive. > > Even if we used the BLT engine, it can't blit between buffers with > different tiling modes, such as an X-tiled non-MSAA ARGB8888 texture > and a Y-tiled CMS ARGB8888 renderbuffer. This is a fundamental > limitation, and the only way around that is to use BLORP. > > Previously, BLORP only handled BlitFramebuffer. This patch adds an > additional frontend for doing CopyTexSubImage. It also makes it the > default. This is partly to increase testing and avoid hiding bugs, > and partly because the BLORP path can already handle more cases. With > trivial extensions, it should be able to handle everything the BLT can. > > This helps PlaneShift massively, which tries to CopyTexSubImage2D > between depth buffers whenever a player casts a spell. Since these > are Y-tiled, we hit meta and software ReadPixels paths, eating 99% CPU > while delivering ~1 FPS. This is particularly bad in an MMO setting > because people cast spells all the time. > > It also helps Xonotic in 4X MSAA mode. At default power management > settings, I measured a 6.35138% +/- 0.672548% performance boost (n=5). > (This data is from v1 of the patch.) > > No Piglit regressions on Ivybridge (v3) or Sandybridge (v2). > > v2: Create a fake intel_renderbuffer to wrap the destination texture > image and then reuse do_blorp_blit rather than reimplementing most > of it. Remove unnecessary clipping code and conditional rendering > check. > > v3: Reuse formats_match() to centralize checks; delete temporary > renderbuffers. Reorganize the code. > > v4: Actually copy stencil when dealing with separate stencil buffers but > packed depth/stencil formats. Tested by a new Piglit test. > > NOTE: This is a candidate for the 9.1 branch. > > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > Cc: Paul Berry <stereotype...@gmail.com> > Reviewed-and-tested-by: Carl Worth <cwo...@cworth.org> [v2] > Reviewed-by: Ian Romanick <ian.d.roman...@intel.com> [v3] > Tested-by: Martin Steigerwald <mar...@lichtvoll.de> [v3] > Reviewed-by: Paul Berry <stereotype...@gmail.com>
_______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
