Re: [wwwdocs] gcc-14/changes.html (AMD GCN): Mention gfx1036 support
Richard Biener wrote: I do wonder whether hot-patching the ELF header from the libgomp plugin with the actual micro-subarch would be possible to make the driver happy. For completeness, there is also the possibility to play with an environment variable as in HSA_OVERRIDE_GFX_VERSION=9.0.0 or HSA_OVERRIDE_GFX_VERSION=11.0.0 Tobias
Re: [wwwdocs] gcc-14/changes.html (AMD GCN): Mention gfx1036 support
On 15/04/2024 13:00, Richard Biener wrote: On Mon, Apr 15, 2024 at 12:04 PM Tobias Burnus wrote: I experimented with some variants to make clearer that each of RDNA2 and RNDA3 applies to two card types, but at the end I settled on the fewest-word version. Comments, remarks, suggestions? (To this change or in general?) Current version: https://gcc.gnu.org/gcc-14/changes.html#amdgcn Compiler flags, listing the the gfx* cards: https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html Tobias PS: On the compiler side, I am looking forward to a .def file which reduces the number of files to change when adding a new gfx* card, given that we have doubled the number of entries. [Well, 1 missing but I know of one WIP addition.] I do wonder whether hot-patching the ELF header from the libgomp plugin with the actual micro-subarch would be possible to make the driver happy. We do query the device ISA when initializing the device so we should be able to massage the ELF header of the object in GOMP_OFFLOAD_load_image at least within some constraints (ideally we'd mark the ELF object as to be matched with a device in some group). This might work in some limited cases, especially if you limit the codegen to some subset of the ISA, but in general the metadata on the kernel entry-points is device-specific. For example, the gfx908 and gfx90a have different granularity on the VGPR count settings. It would probably be possible to generate some matching sets. However, there's probably no need to do that ourselves because the LLVM tools now have new generic ELF flags "gfx9-generic", "gfx10-1-generic", "gfx10-3-generic", and "gfx11-generic" which supposedly do what you want. I've not experimented with them. I don't know if libraries can have the generic variant and still link with the specific variant (the only libraries with kernel entry-points are the libgcc init_array and fini_array). If not it becomes yet another multilib. I'm very sure there's no one binary that will run anywhere for real usecases. Andrew
Re: [wwwdocs] gcc-14/changes.html (AMD GCN): Mention gfx1036 support
On Mon, Apr 15, 2024 at 12:04 PM Tobias Burnus wrote: > > I experimented with some variants to make clearer that each of RDNA2 and > RNDA3 applies to two card types, but at the end I settled on the > fewest-word version. > > Comments, remarks, suggestions? (To this change or in general?) > > Current version: https://gcc.gnu.org/gcc-14/changes.html#amdgcn > > Compiler flags, listing the the gfx* cards: > https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html > > Tobias > > PS: On the compiler side, I am looking forward to a .def file which > reduces the number of files to change when adding a new gfx* card, given > that we have doubled the number of entries. [Well, 1 missing but I know > of one WIP addition.] I do wonder whether hot-patching the ELF header from the libgomp plugin with the actual micro-subarch would be possible to make the driver happy. We do query the device ISA when initializing the device so we should be able to massage the ELF header of the object in GOMP_OFFLOAD_load_image at least within some constraints (ideally we'd mark the ELF object as to be matched with a device in some group). Richard.
Re: [wwwdocs] gcc-14/changes.html (AMD GCN): Mention gfx1036 support
On 15/04/2024 11:03, Tobias Burnus wrote: I experimented with some variants to make clearer that each of RDNA2 and RNDA3 applies to two card types, but at the end I settled on the fewest-word version. Comments, remarks, suggestions? (To this change or in general?) Current version: https://gcc.gnu.org/gcc-14/changes.html#amdgcn Compiler flags, listing the the gfx* cards: https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html Tobias PS: On the compiler side, I am looking forward to a .def file which reduces the number of files to change when adding a new gfx* card, given that we have doubled the number of entries. [Well, 1 missing but I know of one WIP addition.] LGTM Andrew
[wwwdocs] gcc-14/changes.html (AMD GCN): Mention gfx1036 support
I experimented with some variants to make clearer that each of RDNA2 and RNDA3 applies to two card types, but at the end I settled on the fewest-word version. Comments, remarks, suggestions? (To this change or in general?) Current version: https://gcc.gnu.org/gcc-14/changes.html#amdgcn Compiler flags, listing the the gfx* cards: https://gcc.gnu.org/onlinedocs/gcc/AMD-GCN-Options.html Tobias PS: On the compiler side, I am looking forward to a .def file which reduces the number of files to change when adding a new gfx* card, given that we have doubled the number of entries. [Well, 1 missing but I know of one WIP addition.] gcc-14/changes.html (AMD GCN): Mention gfx1036 support diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html index 8ac08e9a..b4c602a5 100644 --- a/htdocs/gcc-14/changes.html +++ b/htdocs/gcc-14/changes.html @@ -623,8 +623,9 @@ a work-in-progress. AMD Radeon (GCN) - Initial support for the AMD Radeon gfx1030 (RDNA2), -gfx1100 and gfx1103 (RDNA3) devices has been + Initial support for the AMD Radeon gfx1030, +gfx1036 (RDNA2), gfx1100 and +gfx1103 (RDNA3) devices has been added. LLVM 15+ (assembler and linker) is https://gcc.gnu.org/install/specific.html#amdgcn-x-amdhsa;>required to support GFX11.
