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
17 namespace llvm {
18
19 namespace 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
57 struct 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
warpSlotSizeGV63 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
maxWarpNumberGV81 constexpr unsigned maxWarpNumber() const {
82 return GV_Max_WG_Size / GV_Warp_Size;
83 }
84 };
85
86 /// For AMDGPU GPUs
87 static constexpr GV AMDGPUGridValues64 = {
88 256, // GV_Slot_Size
89 64, // GV_Warp_Size
90 (1 << 16), // GV_Max_Teams
91 440, // GV_Default_Num_Teams
92 896, // GV_SimpleBufferSize
93 1024, // GV_Max_WG_Size,
94 256, // GV_Default_WG_Size
95 };
96
97 static constexpr GV AMDGPUGridValues32 = {
98 256, // GV_Slot_Size
99 32, // GV_Warp_Size
100 (1 << 16), // GV_Max_Teams
101 440, // GV_Default_Num_Teams
102 896, // GV_SimpleBufferSize
103 1024, // GV_Max_WG_Size,
104 256, // GV_Default_WG_Size
105 };
106
getAMDGPUGridValues()107 template <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
113 static constexpr GV NVPTXGridValues = {
114 256, // GV_Slot_Size
115 32, // GV_Warp_Size
116 (1 << 16), // GV_Max_Teams
117 3200, // GV_Default_Num_Teams
118 896, // GV_SimpleBufferSize
119 1024, // GV_Max_WG_Size
120 128, // GV_Default_WG_Size
121 };
122
123 } // namespace omp
124 } // namespace llvm
125
126 #endif // LLVM_FRONTEND_OPENMP_OMPGRIDVALUES_H
127