[llvm] [OpenMP] Use 'gpuintrin.h' definitions for simple block identifiers (PR #131631)
Joseph Huber via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 17 08:45:41 PDT 2025
https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/131631
Summary:
This patch ports the runtime to use `gpuintrin.h` instead of calling the
builtins for most things. The `lanemask_gt` stuff was left for now with
a fallback.
>From 71d68ed01184b833a6f614251177f0ea1da3ad56 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Mon, 17 Mar 2025 10:43:40 -0500
Subject: [PATCH] [OpenMP] Use 'gpuintrin.h' definitions for simple block
identifiers
Summary:
This patch ports the runtime to use `gpuintrin.h` instead of calling the
builtins for most things. The `lanemask_gt` stuff was left for now with
a fallback.
---
offload/DeviceRTL/include/Mapping.h | 6 +-
offload/DeviceRTL/src/Mapping.cpp | 255 +++++-----------------------
2 files changed, 49 insertions(+), 212 deletions(-)
diff --git a/offload/DeviceRTL/include/Mapping.h b/offload/DeviceRTL/include/Mapping.h
index f892a025159d4..8ba018b5314aa 100644
--- a/offload/DeviceRTL/include/Mapping.h
+++ b/offload/DeviceRTL/include/Mapping.h
@@ -19,9 +19,9 @@ namespace ompx {
namespace mapping {
enum {
- DIM_X = 0,
- DIM_Y = 1,
- DIM_Z = 2,
+ DIM_X = __GPU_X_DIM,
+ DIM_Y = __GPU_Y_DIM,
+ DIM_Z = __GPU_Z_DIM,
};
inline constexpr uint32_t MaxThreadsPerTeam = 1024;
diff --git a/offload/DeviceRTL/src/Mapping.cpp b/offload/DeviceRTL/src/Mapping.cpp
index 641be81cca3ed..a9e027727b04b 100644
--- a/offload/DeviceRTL/src/Mapping.cpp
+++ b/offload/DeviceRTL/src/Mapping.cpp
@@ -14,198 +14,12 @@
#include "DeviceUtils.h"
#include "Interface.h"
#include "State.h"
+#include "gpuintrin.h"
#include "llvm/Frontend/OpenMP/OMPGridValues.h"
using namespace ompx;
-namespace ompx {
-namespace impl {
-
-/// AMDGCN Implementation
-///
-///{
-#ifdef __AMDGPU__
-
-uint32_t getWarpSize() { return __builtin_amdgcn_wavefrontsize(); }
-
-uint32_t getNumberOfThreadsInBlock(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __builtin_amdgcn_workgroup_size_x();
- case 1:
- return __builtin_amdgcn_workgroup_size_y();
- case 2:
- return __builtin_amdgcn_workgroup_size_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-LaneMaskTy activemask() { return __builtin_amdgcn_read_exec(); }
-
-LaneMaskTy lanemaskLT() {
- uint32_t Lane = mapping::getThreadIdInWarp();
- int64_t Ballot = mapping::activemask();
- uint64_t Mask = ((uint64_t)1 << Lane) - (uint64_t)1;
- return Mask & Ballot;
-}
-
-LaneMaskTy lanemaskGT() {
- uint32_t Lane = mapping::getThreadIdInWarp();
- if (Lane == (mapping::getWarpSize() - 1))
- return 0;
- int64_t Ballot = mapping::activemask();
- uint64_t Mask = (~((uint64_t)0)) << (Lane + 1);
- return Mask & Ballot;
-}
-
-uint32_t getThreadIdInWarp() {
- return __builtin_amdgcn_mbcnt_hi(~0u, __builtin_amdgcn_mbcnt_lo(~0u, 0u));
-}
-
-uint32_t getThreadIdInBlock(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __builtin_amdgcn_workitem_id_x();
- case 1:
- return __builtin_amdgcn_workitem_id_y();
- case 2:
- return __builtin_amdgcn_workitem_id_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getNumberOfThreadsInKernel() {
- return __builtin_amdgcn_grid_size_x() * __builtin_amdgcn_grid_size_y() *
- __builtin_amdgcn_grid_size_z();
-}
-
-uint32_t getBlockIdInKernel(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __builtin_amdgcn_workgroup_id_x();
- case 1:
- return __builtin_amdgcn_workgroup_id_y();
- case 2:
- return __builtin_amdgcn_workgroup_id_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getNumberOfBlocksInKernel(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __builtin_amdgcn_grid_size_x() / __builtin_amdgcn_workgroup_size_x();
- case 1:
- return __builtin_amdgcn_grid_size_y() / __builtin_amdgcn_workgroup_size_y();
- case 2:
- return __builtin_amdgcn_grid_size_z() / __builtin_amdgcn_workgroup_size_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getWarpIdInBlock() {
- return impl::getThreadIdInBlock(mapping::DIM_X) / mapping::getWarpSize();
-}
-
-uint32_t getNumberOfWarpsInBlock() {
- return mapping::getNumberOfThreadsInBlock() / mapping::getWarpSize();
-}
-
-#endif
-///}
-
-/// NVPTX Implementation
-///
-///{
-#ifdef __NVPTX__
-
-uint32_t getNumberOfThreadsInBlock(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __nvvm_read_ptx_sreg_ntid_x();
- case 1:
- return __nvvm_read_ptx_sreg_ntid_y();
- case 2:
- return __nvvm_read_ptx_sreg_ntid_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getWarpSize() { return __nvvm_read_ptx_sreg_warpsize(); }
-
-LaneMaskTy activemask() { return __nvvm_activemask(); }
-
-LaneMaskTy lanemaskLT() { return __nvvm_read_ptx_sreg_lanemask_lt(); }
-
-LaneMaskTy lanemaskGT() { return __nvvm_read_ptx_sreg_lanemask_gt(); }
-
-uint32_t getThreadIdInBlock(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __nvvm_read_ptx_sreg_tid_x();
- case 1:
- return __nvvm_read_ptx_sreg_tid_y();
- case 2:
- return __nvvm_read_ptx_sreg_tid_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getThreadIdInWarp() { return __nvvm_read_ptx_sreg_laneid(); }
-
-uint32_t getBlockIdInKernel(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __nvvm_read_ptx_sreg_ctaid_x();
- case 1:
- return __nvvm_read_ptx_sreg_ctaid_y();
- case 2:
- return __nvvm_read_ptx_sreg_ctaid_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getNumberOfBlocksInKernel(int32_t Dim) {
- switch (Dim) {
- case 0:
- return __nvvm_read_ptx_sreg_nctaid_x();
- case 1:
- return __nvvm_read_ptx_sreg_nctaid_y();
- case 2:
- return __nvvm_read_ptx_sreg_nctaid_z();
- };
- UNREACHABLE("Dim outside range!");
-}
-
-uint32_t getNumberOfThreadsInKernel() {
- return impl::getNumberOfThreadsInBlock(0) *
- impl::getNumberOfBlocksInKernel(0) *
- impl::getNumberOfThreadsInBlock(1) *
- impl::getNumberOfBlocksInKernel(1) *
- impl::getNumberOfThreadsInBlock(2) *
- impl::getNumberOfBlocksInKernel(2);
-}
-
-uint32_t getWarpIdInBlock() {
- return impl::getThreadIdInBlock(mapping::DIM_X) / mapping::getWarpSize();
-}
-
-uint32_t getNumberOfWarpsInBlock() {
- return (mapping::getNumberOfThreadsInBlock() + mapping::getWarpSize() - 1) /
- mapping::getWarpSize();
-}
-
-#endif
-///}
-
-} // namespace impl
-} // namespace ompx
-
-/// We have to be deliberate about the distinction of `mapping::` and `impl::`
-/// below to avoid repeating assumptions or including irrelevant ones.
-///{
-
static bool isInLastWarp() {
uint32_t MainTId = (mapping::getNumberOfThreadsInBlock() - 1) &
~(mapping::getWarpSize() - 1);
@@ -236,64 +50,87 @@ bool mapping::isLeaderInWarp() {
return utils::popc(Active & LaneMaskLT) == 0;
}
-LaneMaskTy mapping::activemask() { return impl::activemask(); }
+LaneMaskTy mapping::activemask() { return __gpu_lane_mask(); }
-LaneMaskTy mapping::lanemaskLT() { return impl::lanemaskLT(); }
+LaneMaskTy mapping::lanemaskLT() {
+#ifdef __NVPTX__
+ return __nvvm_read_ptx_sreg_lanemask_lt();
+#else
+ uint32_t Lane = mapping::getThreadIdInWarp();
+ int64_t Ballot = mapping::activemask();
+ uint64_t Mask = ((uint64_t)1 << Lane) - (uint64_t)1;
+ return Mask & Ballot;
+#endif
+}
-LaneMaskTy mapping::lanemaskGT() { return impl::lanemaskGT(); }
+LaneMaskTy mapping::lanemaskGT() {
+#ifdef __NVPTX__
+ return __nvvm_read_ptx_sreg_lanemask_gt();
+#else
+ uint32_t Lane = mapping::getThreadIdInWarp();
+ if (Lane == (mapping::getWarpSize() - 1))
+ return 0;
+ int64_t Ballot = mapping::activemask();
+ uint64_t Mask = (~((uint64_t)0)) << (Lane + 1);
+ return Mask & Ballot;
+#endif
+}
uint32_t mapping::getThreadIdInWarp() {
- uint32_t ThreadIdInWarp = impl::getThreadIdInWarp();
- ASSERT(ThreadIdInWarp < impl::getWarpSize(), nullptr);
+ uint32_t ThreadIdInWarp = __gpu_lane_id();
+ ASSERT(ThreadIdInWarp < mapping::getWarpSize(), nullptr);
return ThreadIdInWarp;
}
uint32_t mapping::getThreadIdInBlock(int32_t Dim) {
- uint32_t ThreadIdInBlock = impl::getThreadIdInBlock(Dim);
+ uint32_t ThreadIdInBlock = __gpu_thread_id(Dim);
return ThreadIdInBlock;
}
-uint32_t mapping::getWarpSize() { return impl::getWarpSize(); }
+uint32_t mapping::getWarpSize() { return __gpu_num_lanes(); }
uint32_t mapping::getMaxTeamThreads(bool IsSPMD) {
uint32_t BlockSize = mapping::getNumberOfThreadsInBlock();
// If we are in SPMD mode, remove one warp.
- return BlockSize - (!IsSPMD * impl::getWarpSize());
+ return BlockSize - (!IsSPMD * mapping::getWarpSize());
}
uint32_t mapping::getMaxTeamThreads() {
return mapping::getMaxTeamThreads(mapping::isSPMDMode());
}
uint32_t mapping::getNumberOfThreadsInBlock(int32_t Dim) {
- return impl::getNumberOfThreadsInBlock(Dim);
+ return __gpu_num_threads(Dim);
}
uint32_t mapping::getNumberOfThreadsInKernel() {
- return impl::getNumberOfThreadsInKernel();
+ return mapping::getNumberOfThreadsInBlock(0) *
+ mapping::getNumberOfBlocksInKernel(0) *
+ mapping::getNumberOfThreadsInBlock(1) *
+ mapping::getNumberOfBlocksInKernel(1) *
+ mapping::getNumberOfThreadsInBlock(2) *
+ mapping::getNumberOfBlocksInKernel(2);
}
uint32_t mapping::getWarpIdInBlock() {
- uint32_t WarpID = impl::getWarpIdInBlock();
- ASSERT(WarpID < impl::getNumberOfWarpsInBlock(), nullptr);
+ uint32_t WarpID =
+ mapping::getThreadIdInBlock(mapping::DIM_X) / mapping::getWarpSize();
+ ASSERT(WarpID < mapping::getNumberOfWarpsInBlock(), nullptr);
return WarpID;
}
uint32_t mapping::getBlockIdInKernel(int32_t Dim) {
- uint32_t BlockId = impl::getBlockIdInKernel(Dim);
- ASSERT(BlockId < impl::getNumberOfBlocksInKernel(Dim), nullptr);
+ uint32_t BlockId = __gpu_block_id(Dim);
+ ASSERT(BlockId < mapping::getNumberOfBlocksInKernel(Dim), nullptr);
return BlockId;
}
uint32_t mapping::getNumberOfWarpsInBlock() {
- uint32_t NumberOfWarpsInBlocks = impl::getNumberOfWarpsInBlock();
- ASSERT(impl::getWarpIdInBlock() < NumberOfWarpsInBlocks, nullptr);
- return NumberOfWarpsInBlocks;
+ return (mapping::getNumberOfThreadsInBlock() + mapping::getWarpSize() - 1) /
+ mapping::getWarpSize();
}
uint32_t mapping::getNumberOfBlocksInKernel(int32_t Dim) {
- uint32_t NumberOfBlocks = impl::getNumberOfBlocksInKernel(Dim);
- ASSERT(impl::getBlockIdInKernel(Dim) < NumberOfBlocks, nullptr);
- return NumberOfBlocks;
+ return __gpu_num_blocks(Dim);
}
uint32_t mapping::getNumberOfProcessorElements() {
@@ -326,11 +163,11 @@ extern "C" {
}
[[gnu::noinline]] uint32_t __kmpc_get_hardware_num_threads_in_block() {
- return impl::getNumberOfThreadsInBlock(mapping::DIM_X);
+ return mapping::getNumberOfThreadsInBlock(mapping::DIM_X);
}
[[gnu::noinline]] uint32_t __kmpc_get_warp_size() {
- return impl::getWarpSize();
+ return mapping::getWarpSize();
}
}
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