Hi Christian, Am Dienstag, den 05.06.2018, 17:43 +0200 schrieb Christian Gmeiner: > Am Di., 5. Juni 2018 um 16:40 Uhr schrieb Philipp Zabel > > <p.za...@pengutronix.de>: > > > > Hi! > > > > we have been interested in NIR support for etnaviv for a while, for the > > obvious reasons: gaining access to common optimizations, better support > > for non-trivial code transformations, better register allocation, and > > the promise of OpenCL and SPIR-V support in the future. > > > > Michael and I have used our annual exploratory "tech week" last year > > and last week to get acquainted with NIR and the Vivante GPUs a bit and > > to get started compiling NIR shaders from the GLSL compiler to Vivante > > machine code. > > > > The following patches are still very much work in progress. Until now, > > this has only been tested with kmscube, weston, and glmark2 (and some > > benchmarks are not working yet, missing instruction implementations). > > We haven't even dared to run piglit yet. At this point we'd very much > > like some feedback on where we are on the right path, and where things > > could be done in a better way. > > The NIR compiler is placed next to the current TGSI translation layer, > > and still uses the same backend for code emission. NIR support is > > disabled by default, and can be enabled using the etnaviv environment > > option: ETNA_MESA_DEBUG="nir", so this could be merged without side > > effects, once it is deemed acceptable, to support further development > > in-tree. > > > > Due to the shared global register file, reducing the amount of temporary > > registers used by a shader is important for parallelism. We have added > > added a layer of virtual registers with less than four components over > > each vec4 base register using the register allocator utility, and use > > source swizzles and destination write masks to reuse the free components > > of partially occupied registers if possible. > > We use the NIR global registers, indexed to represent the registers in > > the global temporary register file, which allows us to do register > > assignment in NIR and then reuse the current code emitter without > > introducing another intermediate representation. > > > > There are already a few Vivante specific lowering passes, but we > > notably are still missing support for loops, and for lowering sin, > > cos and log functions to the Vivante specific hardware instructions > > that need prescaling and post-multiplication of the results' x and > > y components (or to replace them with approximations where the > > instructions are not supported). > > > > Thanks for this nice patch series. I have been working for too long on > the nir topic > for etnaviv and never pushed any patches (which is quite sad). I have taken > another route to tackle it. I have started with a low level library to > generate valid > Vivante binaries and to be able to disassemble them. On top of this, I > have an eir > library which is a simple block based ir which makes use of the low-level lib. > And the last thing is the actual compiler which is nir based. All life outside > of the gallium driver and have some gtest based unit tests. My main goal was > to > start from a green field without looking at the current tgsi based compiler. > > I will have a deeper look at your patches and review them. I am quite > unsure what I > will do with my current code. I think the best would be to clean it up > and push it.
Did you get a chance to look at this? Will you be able to provide some review comments? This code is already starting to bitrot and it would be a shame if the work that has gone into this is going down the drain due to being stuck on the mailinglist. Regards, Lucas _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
