Mesa3D Graphics Library (Bleeding edge ray tracing branches)
Go to file
Francisco Jerez b54b67e067 intel/fs: Switch to standard vector layout for barycentrics at optimization time.
This involves permuting the registers of barycentric vectors to have
the standard X[0-n] Y[0-n] layout at NIR translation time.
Barycentrics are converted to the format expected by the PLN
instruction in the lower_barycentrics() pass run after the
optimization loop.

Main reason is correctness of SIMD32 fragment shaders.  The
shuffle_from_pln_layout() and shuffle_to_pln_layout() helpers used
during NIR translation are busted for SIMD32.  This leads to serious
corruption at present with INTEL_DEBUG=do32, especially on Gen11+
where these helpers are hit more frequently due to the lack of a
hardware PLN instruction.

Of course one could have chosen to fix those helpers instead, but
there is another far more subtle issue that was reported during review
of the SIMD32 fragment shader codegen changes: The SIMD splitting pass
currently handles SIMD32 barycentric vectors as if they had the
standard X[0-n] Y[0-n] layout, even though they are interleaved for
the PLN instruction, which causes incorrect execution masks to be
applied to the MOVs unzipping barycentric vectors in cases where a
LINTERP instruction occurs under non-uniform control flow.

I'm not aware of any conformance regressions due to the latter issue
at present, but for our peace of mind let's move the conversion to the
PLN layout into the lower_barycentrics() pass run after
lower_simd_width().

This leads to the following shader-db improvements (including SIMD32
shaders) in combination with the previous back-end preparation changes
-- Without them (especially the copy propagation changes) this would
lead to a massive number of regressions.  On ICL:

   total instructions in shared programs: 20662316 -> 20466903 (-0.95%)
   instructions in affected programs: 10538474 -> 10343061 (-1.85%)
   helped: 68775
   HURT: 6

   total spills in shared programs: 8938 -> 8748 (-2.13%)
   spills in affected programs: 376 -> 186 (-50.53%)
   helped: 9
   HURT: 5

   total fills in shared programs: 8965 -> 8663 (-3.37%)
   fills in affected programs: 965 -> 663 (-31.30%)
   helped: 9
   HURT: 6

   LOST:   146
   GAINED: 43

On SKL:

   total instructions in shared programs: 18725867 -> 18614912 (-0.59%)
   instructions in affected programs: 3876590 -> 3765635 (-2.86%)
   helped: 27492
   HURT: 2

   LOST:   191
   GAINED: 417

On SNB:

   total instructions in shared programs: 14573613 -> 13980646 (-4.07%)
   instructions in affected programs: 5199074 -> 4606107 (-11.41%)
   helped: 29998
   HURT: 0

   LOST:   21
   GAINED: 30

Results are somewhat less impressive but still significant without
SIMD32 fragment shaders enabled.  On ICL:

   total instructions in shared programs: 16148728 -> 16061659 (-0.54%)
   instructions in affected programs: 6114788 -> 6027719 (-1.42%)
   helped: 42046
   HURT: 6

   total spills in shared programs: 8218 -> 8028 (-2.31%)
   spills in affected programs: 376 -> 186 (-50.53%)
   helped: 9
   HURT: 5

   total fills in shared programs: 8953 -> 8651 (-3.37%)
   fills in affected programs: 965 -> 663 (-31.30%)
   helped: 9
   HURT: 6

   LOST:   0
   GAINED: 3

On SKL:

   total instructions in shared programs: 14927994 -> 14926738 (-0.01%)
   instructions in affected programs: 168850 -> 167594 (-0.74%)
   helped: 711
   HURT: 2

On SNB:

   total instructions in shared programs: 10770538 -> 10734403 (-0.34%)
   instructions in affected programs: 2702172 -> 2666037 (-1.34%)
   helped: 17818
   HURT: 0

All of the hurt shaders are either spilling slightly more or emitting
additional NOP instructions due to the SIMD16 POW workaround for
Gen8-9 combined with differences in scheduling.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
2020-01-17 13:23:12 -08:00
.appveyor Appveyor: Quickly fix meson build. 2019-11-14 21:45:23 +00:00
.gitlab-ci gitlab-ci: fix missing caselist.css/xsl 2020-01-15 19:03:56 +00:00
bin meson: simplify install_megadrivers.py invocation 2019-12-27 22:43:34 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs anv: enable VK_KHR_swapchain_mutable_format 2020-01-17 18:27:29 +00:00
doxygen
include vulkan: Update the XML and headers to 1.2.131 2020-01-15 08:07:04 -06:00
scons scons: Bump C standard to gnu11 on macOS 10.15. 2019-11-29 12:38:29 +00:00
src intel/fs: Switch to standard vector layout for barycentrics at optimization time. 2020-01-17 13:23:12 -08:00
subprojects meson: use github URL for wraps instead of completely unreliable wrapdb 2020-01-16 23:06:43 +00:00
.dir-locals.el
.editorconfig editorconfig: Fix meson style 2019-05-24 18:44:18 +00:00
.gitignore intel/tools: Add unit tests for assembler 2019-05-07 14:33:48 -07:00
.gitlab-ci.yml gitlab-ci: Stop using manual jobs for merge requests 2020-01-15 10:31:01 +00:00
.mailmap .mailmap: use correct email address 2019-12-21 17:50:01 +00:00
.travis.yml travis: autodetect python version instead of hard-coding it 2019-12-21 20:23:08 +00:00
Android.common.mk android: mesa: Revert "android: mesa: revert "Enable asm unconditionally"" 2019-11-12 18:09:43 +00:00
Android.mk android: mesa: Revert "android: mesa: revert "Enable asm unconditionally"" 2019-11-12 18:09:43 +00:00
CleanSpec.mk CleanSpec.mk: Remove HOST_OUT_release 2018-08-02 15:42:40 -06:00
README.rst docs: remove mailing list as way of submitting patches 2019-12-12 09:09:50 +11:00
REVIEWERS REVIEWERS: add VMware reviewers 2019-10-18 16:42:40 +00:00
SConstruct scons: Fix force_scons parsing. 2019-10-26 08:23:48 +01:00
VERSION Bump VERSION to 20.0.0-devel 2019-10-30 14:56:02 -07:00
appveyor.yml Appveyor: Quickly fix meson build. 2019-11-14 21:45:23 +00:00
common.py scons: Print a deprecation warning about using scons on not windows 2019-10-24 18:33:50 +00:00
meson.build meson: Enable -Werror=int-conversion. 2020-01-02 11:47:02 +00:00
meson_options.txt meson: Add a "prefer_iris" build option 2019-12-02 12:56:27 -08:00

README.rst

`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library
======================================================


Source
------

This repository lives at https://gitlab.freedesktop.org/mesa/mesa.
Other repositories are likely forks, and code found there is not supported.


Build & install
---------------

You can find more information in our documentation (`docs/install.html
<https://mesa3d.org/install.html>`_), but the recommended way is to use
Meson (`docs/meson.html <https://mesa3d.org/meson.html>`_):

.. code-block:: sh

  $ mkdir build
  $ cd build
  $ meson ..
  $ sudo ninja install


Support
-------

Many Mesa devs hang on IRC; if you're not sure which channel is
appropriate, you should ask your question on `Freenode's #dri-devel
<irc://chat.freenode.net#dri-devel>`_, someone will redirect you if
necessary.
Remember that not everyone is in the same timezone as you, so it might
take a while before someone qualified sees your question.
To figure out who you're talking to, or which nick to ping for your
question, check out `Who's Who on IRC
<https://dri.freedesktop.org/wiki/WhosWho/>`_.

The next best option is to ask your question in an email to the
mailing lists: `mesa-dev\@lists.freedesktop.org
<https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_


Bug reports
-----------

If you think something isn't working properly, please file a bug report
(`docs/bugs.html <https://mesa3d.org/bugs.html>`_).


Contributing
------------

Contributions are welcome, and step-by-step instructions can be found in our
documentation (`docs/submittingpatches.html
<https://mesa3d.org/submittingpatches.html>`_).

Note that Mesa uses gitlab for patches submission, review and discussions.