Re: [Mesa-dev] Testing optimizer
On Tue, Dec 17, 2013 at 10:59 AM, Paul Berry wrote: > On 17 December 2013 08:46, Tom Stellard wrote: > >> On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: >> > Hi all, >> > >> > Is there a way to see the machine code that is generated by the GLSL >> > compiler for all GPU instruction sets? For example, I would like to >> know if >> > the optimizer optimizes certain (equivalent) constructs (or not), and >> avoid >> > them if possible. I know there is a lot to optimization on GPUs that I >> > don't know, but I'd still like to get some ballpark estimates. For >> example, >> > I'm curious whether: >> >> Each driver has its own environment variable for dumping machine code. >> >> llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa >> with --enable-debug for this to work) >> r300g: RADEON_DEBUG=fp,vp >> r600g, radeonsi: R600_DEBUG=ps,vs >> >> I'm not sure what the other drivers use. >> >> -Tom >> > > I believe every driver also supports MESA_GLSL=dump, which prints out the > IR both before and after linking (you'll want to look at the version after > linking to see what optimizations have been applied, since some > optimizations happen at link time). Looking at the IR rather than the > machine code is more likely to give you the information you need, since > Mesa performs the same IR-level optimizations on all architectures, whereas > the optimizations that happen at machine code level are vastly different > from one driver to the next. > > I do want to see both, actually. For example, if a driver implements a specific optimization (machine code level) and another driver clearly does not, then that would be considered "interesting" to me. > Another thing which might be useful to you is Aras Pranckevičius's > "glsl-optimizer" project (https://github.com/aras-p/glsl-optimizer), > which performs Mesa's IR-level optimizations on a shader and then > translates it from IR back to GLSL. > > Paul > > Thanks to everyone for the great tips! > >> > >> > //let p1, p2, p3 be vec2 uniforms >> > >> > vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) >> > >> > produces identical machine code as: >> > >> > vec4(p1+p2+p3, 0, 1); >> > >> > for all architectures supported by Mesa. >> >> > ___ >> > mesa-dev mailing list >> > mesa-dev@lists.freedesktop.org >> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev >> >> ___ >> mesa-dev mailing list >> mesa-dev@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/mesa-dev >> > > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Testing optimizer
On 17 December 2013 11:07, Patrick Baggett wrote: > > > > On Tue, Dec 17, 2013 at 10:59 AM, Paul Berry wrote: > >> On 17 December 2013 08:46, Tom Stellard wrote: >> >>> On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: >>> > Hi all, >>> > >>> > Is there a way to see the machine code that is generated by the GLSL >>> > compiler for all GPU instruction sets? For example, I would like to >>> know if >>> > the optimizer optimizes certain (equivalent) constructs (or not), and >>> avoid >>> > them if possible. I know there is a lot to optimization on GPUs that I >>> > don't know, but I'd still like to get some ballpark estimates. For >>> example, >>> > I'm curious whether: >>> >>> Each driver has its own environment variable for dumping machine code. >>> >>> llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa >>> with --enable-debug for this to work) >>> r300g: RADEON_DEBUG=fp,vp >>> r600g, radeonsi: R600_DEBUG=ps,vs >>> >>> I'm not sure what the other drivers use. >>> >>> -Tom >>> >> >> I believe every driver also supports MESA_GLSL=dump, which prints out the >> IR both before and after linking (you'll want to look at the version after >> linking to see what optimizations have been applied, since some >> optimizations happen at link time). Looking at the IR rather than the >> machine code is more likely to give you the information you need, since >> Mesa performs the same IR-level optimizations on all architectures, whereas >> the optimizations that happen at machine code level are vastly different >> from one driver to the next. >> >> > I do want to see both, actually. For example, if a driver implements a > specific optimization (machine code level) and another driver clearly does > not, then that would be considered "interesting" to me. > Ok, in that case the environment variable you want for seeing the generated assembly code for Intel is: INTEL_DEBUG=vs,fs,gs > > > >> Another thing which might be useful to you is Aras Pranckevičius's >> "glsl-optimizer" project (https://github.com/aras-p/glsl-optimizer), >> which performs Mesa's IR-level optimizations on a shader and then >> translates it from IR back to GLSL. >> >> Paul >> >> > Thanks to everyone for the great tips! > > >> >>> > >>> > //let p1, p2, p3 be vec2 uniforms >>> > >>> > vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) >>> > >>> > produces identical machine code as: >>> > >>> > vec4(p1+p2+p3, 0, 1); >>> > >>> > for all architectures supported by Mesa. >>> >>> > ___ >>> > mesa-dev mailing list >>> > mesa-dev@lists.freedesktop.org >>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev >>> >>> ___ >>> mesa-dev mailing list >>> mesa-dev@lists.freedesktop.org >>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev >>> >> >> > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Testing optimizer
ST_DEBUG=tgsi ... is also useful. It dumps all shaders generated by mesa_to_tgsi and glsl_to_tgsi and it's easier to read than the GLSL IR. Marek On Tue, Dec 17, 2013 at 5:46 PM, Tom Stellard wrote: > On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: >> Hi all, >> >> Is there a way to see the machine code that is generated by the GLSL >> compiler for all GPU instruction sets? For example, I would like to know if >> the optimizer optimizes certain (equivalent) constructs (or not), and avoid >> them if possible. I know there is a lot to optimization on GPUs that I >> don't know, but I'd still like to get some ballpark estimates. For example, >> I'm curious whether: > > Each driver has its own environment variable for dumping machine code. > > llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa > with --enable-debug for this to work) > r300g: RADEON_DEBUG=fp,vp > r600g, radeonsi: R600_DEBUG=ps,vs > > I'm not sure what the other drivers use. > > -Tom > >> >> //let p1, p2, p3 be vec2 uniforms >> >> vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) >> >> produces identical machine code as: >> >> vec4(p1+p2+p3, 0, 1); >> >> for all architectures supported by Mesa. > >> ___ >> mesa-dev mailing list >> mesa-dev@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/mesa-dev > > ___ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Testing optimizer
On 17 December 2013 08:46, Tom Stellard wrote: > On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: > > Hi all, > > > > Is there a way to see the machine code that is generated by the GLSL > > compiler for all GPU instruction sets? For example, I would like to know > if > > the optimizer optimizes certain (equivalent) constructs (or not), and > avoid > > them if possible. I know there is a lot to optimization on GPUs that I > > don't know, but I'd still like to get some ballpark estimates. For > example, > > I'm curious whether: > > Each driver has its own environment variable for dumping machine code. > > llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa > with --enable-debug for this to work) > r300g: RADEON_DEBUG=fp,vp > r600g, radeonsi: R600_DEBUG=ps,vs > > I'm not sure what the other drivers use. > > -Tom > I believe every driver also supports MESA_GLSL=dump, which prints out the IR both before and after linking (you'll want to look at the version after linking to see what optimizations have been applied, since some optimizations happen at link time). Looking at the IR rather than the machine code is more likely to give you the information you need, since Mesa performs the same IR-level optimizations on all architectures, whereas the optimizations that happen at machine code level are vastly different from one driver to the next. Another thing which might be useful to you is Aras Pranckevičius's "glsl-optimizer" project (https://github.com/aras-p/glsl-optimizer), which performs Mesa's IR-level optimizations on a shader and then translates it from IR back to GLSL. Paul > > > > //let p1, p2, p3 be vec2 uniforms > > > > vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) > > > > produces identical machine code as: > > > > vec4(p1+p2+p3, 0, 1); > > > > for all architectures supported by Mesa. > > > ___ > > mesa-dev mailing list > > mesa-dev@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > > ___ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Testing optimizer
On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: > Hi all, > > Is there a way to see the machine code that is generated by the GLSL > compiler for all GPU instruction sets? For example, I would like to know if > the optimizer optimizes certain (equivalent) constructs (or not), and avoid > them if possible. I know there is a lot to optimization on GPUs that I > don't know, but I'd still like to get some ballpark estimates. For example, > I'm curious whether: Each driver has its own environment variable for dumping machine code. llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa with --enable-debug for this to work) r300g: RADEON_DEBUG=fp,vp r600g, radeonsi: R600_DEBUG=ps,vs I'm not sure what the other drivers use. -Tom > > //let p1, p2, p3 be vec2 uniforms > > vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) > > produces identical machine code as: > > vec4(p1+p2+p3, 0, 1); > > for all architectures supported by Mesa. > ___ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] Testing optimizer
Hi all, Is there a way to see the machine code that is generated by the GLSL compiler for all GPU instruction sets? For example, I would like to know if the optimizer optimizes certain (equivalent) constructs (or not), and avoid them if possible. I know there is a lot to optimization on GPUs that I don't know, but I'd still like to get some ballpark estimates. For example, I'm curious whether: //let p1, p2, p3 be vec2 uniforms vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) produces identical machine code as: vec4(p1+p2+p3, 0, 1); for all architectures supported by Mesa. ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
