1//====--- OMPGridValues.h - Language-specific address spaces --*- C++ -*-====//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// \brief Provides definitions for Target specific Grid Values
11///
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_FRONTEND_OPENMP_OMPGRIDVALUES_H
15#define LLVM_FRONTEND_OPENMP_OMPGRIDVALUES_H
16
17namespace llvm {
18
19namespace omp {
20
21/// \brief Defines various target-specific GPU grid values that must be
22/// consistent between host RTL (plugin), device RTL, and clang.
23/// We can change grid values for a "fat" binary so that different
24/// passes get the correct values when generating code for a
25/// multi-target binary. Both amdgcn and nvptx values are stored in
26/// this file. In the future, should there be differences between GPUs
27/// of the same architecture, then simply make a different array and
28/// use the new array name.
29///
30/// Example usage in clang:
31/// const unsigned slot_size =
32/// ctx.GetTargetInfo().getGridValue().GV_Warp_Size;
33///
34/// Example usage in libomptarget/deviceRTLs:
35/// #include "llvm/Frontend/OpenMP/OMPGridValues.h"
36/// #ifdef __AMDGPU__
37/// #define GRIDVAL AMDGPUGridValues
38/// #else
39/// #define GRIDVAL NVPTXGridValues
40/// #endif
41/// ... Then use this reference for GV_Warp_Size in the deviceRTL source.
42/// llvm::omp::GRIDVAL().GV_Warp_Size
43///
44/// Example usage in libomptarget hsa plugin:
45/// #include "llvm/Frontend/OpenMP/OMPGridValues.h"
46/// #define GRIDVAL AMDGPUGridValues
47/// ... Then use this reference to access GV_Warp_Size in the hsa plugin.
48/// llvm::omp::GRIDVAL().GV_Warp_Size
49///
50/// Example usage in libomptarget cuda plugin:
51/// #include "llvm/Frontend/OpenMP/OMPGridValues.h"
52/// #define GRIDVAL NVPTXGridValues
53/// ... Then use this reference to access GV_Warp_Size in the cuda plugin.
54/// llvm::omp::GRIDVAL().GV_Warp_Size
55///
56
57struct GV {
58 /// The size reserved for data in a shared memory slot.
59 unsigned GV_Slot_Size;
60 /// The default value of maximum number of threads in a worker warp.
61 unsigned GV_Warp_Size;
62
63 constexpr unsigned warpSlotSize() const {
64 return GV_Warp_Size * GV_Slot_Size;
65 }
66
67 /// the maximum number of teams.
68 unsigned GV_Max_Teams;
69 // The default number of teams in the absence of any other information.
70 unsigned GV_Default_Num_Teams;
71
72 // An alternative to the heavy data sharing infrastructure that uses global
73 // memory is one that uses device __shared__ memory. The amount of such space
74 // (in bytes) reserved by the OpenMP runtime is noted here.
75 unsigned GV_SimpleBufferSize;
76 // The absolute maximum team size for a working group
77 unsigned GV_Max_WG_Size;
78 // The default maximum team size for a working group
79 unsigned GV_Default_WG_Size;
80
81 constexpr unsigned maxWarpNumber() const {
82 return GV_Max_WG_Size / GV_Warp_Size;
83 }
84};
85
86/// For AMDGPU GPUs
87static constexpr GV AMDGPUGridValues64 = {
88 .GV_Slot_Size: 256, // GV_Slot_Size
89 .GV_Warp_Size: 64, // GV_Warp_Size
90 .GV_Max_Teams: (1 << 16), // GV_Max_Teams
91 .GV_Default_Num_Teams: 440, // GV_Default_Num_Teams
92 .GV_SimpleBufferSize: 896, // GV_SimpleBufferSize
93 .GV_Max_WG_Size: 1024, // GV_Max_WG_Size,
94 .GV_Default_WG_Size: 256, // GV_Default_WG_Size
95};
96
97static constexpr GV AMDGPUGridValues32 = {
98 .GV_Slot_Size: 256, // GV_Slot_Size
99 .GV_Warp_Size: 32, // GV_Warp_Size
100 .GV_Max_Teams: (1 << 16), // GV_Max_Teams
101 .GV_Default_Num_Teams: 440, // GV_Default_Num_Teams
102 .GV_SimpleBufferSize: 896, // GV_SimpleBufferSize
103 .GV_Max_WG_Size: 1024, // GV_Max_WG_Size,
104 .GV_Default_WG_Size: 256, // GV_Default_WG_Size
105};
106
107template <unsigned wavesize> constexpr const GV &getAMDGPUGridValues() {
108 static_assert(wavesize == 32 || wavesize == 64, "Unexpected wavesize");
109 return wavesize == 32 ? AMDGPUGridValues32 : AMDGPUGridValues64;
110}
111
112/// For Nvidia GPUs
113static constexpr GV NVPTXGridValues = {
114 .GV_Slot_Size: 256, // GV_Slot_Size
115 .GV_Warp_Size: 32, // GV_Warp_Size
116 .GV_Max_Teams: (1 << 16), // GV_Max_Teams
117 .GV_Default_Num_Teams: 3200, // GV_Default_Num_Teams
118 .GV_SimpleBufferSize: 896, // GV_SimpleBufferSize
119 .GV_Max_WG_Size: 1024, // GV_Max_WG_Size
120 .GV_Default_WG_Size: 128, // GV_Default_WG_Size
121};
122
123} // namespace omp
124} // namespace llvm
125
126#endif // LLVM_FRONTEND_OPENMP_OMPGRIDVALUES_H
127

source code of include/llvm-17/llvm/Frontend/OpenMP/OMPGridValues.h