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This patch implements "managed" memory for AMD GCN GPUs in OpenMP. It builds on the support added to the NVPTX libgomp for CUDA Managed Memory, a week or two ago. These features were first posted here a few years ago, as part of a larger Unified Shared Memory patch series, and then in a slightly changed version just over a year ago. Hopefully this time the controversial bits have been removed. Since we do not use HIP we cannot use hipMallocManaged, so this patch attempts to replicate the same effect by setting the appropriate attributes. This works on more devices than support proper USM, but still I cannot be sure that the settings are correct for every device out there (I have tested on gfx900, gfx906, gfx908, gfx90a, and gfx1100). The HSA header file update uses the most recent files relicensed for us by AMD, at the time of the first patch posting. Those files have certainly moved on in the upstream sources, but I did not ask to get those relicensed. include/ChangeLog: * hsa.h: Import newer version. * hsa_ext_amd.h: Likewise. * hsa_ext_image.h: Likewise. libgomp/ChangeLog: * Makefile.in: Regenerate. * libgomp-plugin.h (gomp_simple_alloc_init_context): New prototype. (gomp_simple_alloc_register_memory): New prototype. (gomp_simple_alloc): New prototype. (gomp_simple_free): New prototype. (gomp_simple_realloc): New prototype. * libgomp.h (gomp_simple_alloc_init_context): Move to libgomp-plugin.h. (gomp_simple_alloc_register_memory): Likewise. (gomp_simple_alloc): Likewise. (gomp_simple_free): Likewise. (gomp_simple_realloc): Likewise. * libgomp.texi: Update AMD managed memory description. * plugin/Makefrag.am (libgomp_plugin_gcn_la_SOURCES): Add simple-allocator.c and plugin/mutex.c. * plugin/plugin-gcn.c: Include sys/mman.h and unistd.h. (struct hsa_runtime_fn_info): Add hsa_amd_svm_attributes_set_fn. (dump_hsa_system_info): Add HSA_AMD_SYSTEM_INFO_SVM_SUPPORTED and HSA_AMD_SYSTEM_INFO_SVM_ACCESSIBLE_BY_DEFAULT to the GCN_DEBUG output. (init_hsa_runtime_functions): Add hsa_amd_svm_attributes_set. (isa_matches_agent): Add a new error message for the case where the ISA doesn't match but the name does. (managed_ctx): New variable. (managed_heap_create): New function. (GOMP_OFFLOAD_managed_alloc): Likewise. (GOMP_OFFLOAD_managed_free): Likewise. * simple-allocator.c (gomp_fatal): New macro. * testsuite/lib/libgomp.exp (check_effective_target_omp_managedmem): Add amdgcn support checker. (check_effective_target_offload_target_amdgcn_with_xnack): New. * testsuite/libgomp.c-c++-common/requires-4.c: Ignore xnack warning. * testsuite/libgomp.c-c++-common/requires-4a.c: Ignore xnack warning. * testsuite/libgomp.c-c++-common/requires-5.c: Ignore xnack warning. * testsuite/libgomp.c++/alloc-managed-1.C: Add -mxnack=on, if needed. * testsuite/libgomp.c/alloc-managed-1.c: Likewise. * testsuite/libgomp.c/alloc-managed-2.c: Likewise. * testsuite/libgomp.c/alloc-managed-3.c: Likewise. * testsuite/libgomp.c/alloc-managed-4.c: Likewise. * testsuite/libgomp.fortran/alloc-managed-1.f90: Likewise. * plugin/mutex.c: New file.
59 lines
1.9 KiB
C
59 lines
1.9 KiB
C
/* Mutex implementation for libgomp plugins.
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Copyright (C) 2025 Free Software Foundation, Inc.
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Contributed by BayLibre
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This file is part of the GNU Offloading and Multi Processing Library
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(libgomp).
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Libgomp is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* This is a minimal implementation of the gomp_mutex_t spinlocks, but
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without all the dependencies used by the config/linux/mutex implementation.
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At the time of writing, this is only used by simple_alloc which has
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short-lived locks and should be fine with these. The actual locks are in
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a header file, so only the fallback "slow" functions are needed here. */
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#include "config.h"
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#include <unistd.h>
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#include "libgomp.h"
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#ifndef HAVE_SYNC_BUILTINS
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#error "HAVE_SYNC_BUILTINS is required to build this"
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#endif
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void
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gomp_mutex_lock_slow (gomp_mutex_t *mutex, int oldval)
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{
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while (oldval == 1)
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{
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usleep (1);
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oldval = __atomic_exchange_n (mutex, 1, __ATOMIC_ACQUIRE);
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}
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}
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void
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gomp_mutex_unlock_slow (gomp_mutex_t *mutex)
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{
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GOMP_PLUGIN_fatal ("gomp_mutex_unlock_slow should be unreachable");
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}
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