//===------ State.cpp - OpenMP State & ICV interface ------------- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//===----------------------------------------------------------------------===//
#include "Shared/Environment.h"
#include "Allocator.h"
#include "Configuration.h"
#include "Debug.h"
#include "Interface.h"
#include "LibC.h"
#include "Mapping.h"
#include "State.h"
#include "Synchronization.h"
#include "Types.h"
#include "Utils.h"
using namespace ompx;
#pragma omp begin declare target device_type(nohost)
/// Memory implementation
///
///{
/// External symbol to access dynamic shared memory.
[[gnu::aligned(
allocator::ALIGNMENT)]] extern unsigned char DynamicSharedBuffer[];
#pragma omp allocate(DynamicSharedBuffer) allocator(omp_pteam_mem_alloc)
/// The kernel environment passed to the init method by the compiler.
static KernelEnvironmentTy *SHARED(KernelEnvironmentPtr);
/// The kernel launch environment passed as argument to the kernel by the
/// runtime.
static KernelLaunchEnvironmentTy *SHARED(KernelLaunchEnvironmentPtr);
///}
namespace {
/// Fallback implementations are missing to trigger a link time error.
/// Implementations for new devices, including the host, should go into a
/// dedicated begin/end declare variant.
///
///{
extern "C" {
#ifdef __AMDGPU__
[[gnu::weak]] void *malloc(size_t Size) { return allocator::alloc(Size); }
[[gnu::weak]] void free(void *Ptr) { allocator::free(Ptr); }
#else
[[gnu::weak, gnu::leaf]] void *malloc(size_t Size);
[[gnu::weak, gnu::leaf]] void free(void *Ptr);
#endif
}
///}
/// A "smart" stack in shared memory.
///
/// The stack exposes a malloc/free interface but works like a stack internally.
/// In fact, it is a separate stack *per warp*. That means, each warp must push
/// and pop symmetrically or this breaks, badly. The implementation will (aim
/// to) detect non-lock-step warps and fallback to malloc/free. The same will
/// happen if a warp runs out of memory. The master warp in generic memory is
/// special and is given more memory than the rest.
///
struct SharedMemorySmartStackTy {
/// Initialize the stack. Must be called by all threads.
void init(bool IsSPMD);
/// Allocate \p Bytes on the stack for the encountering thread. Each thread
/// can call this function.
void *push(uint64_t Bytes);
/// Deallocate the last allocation made by the encountering thread and pointed
/// to by \p Ptr from the stack. Each thread can call this function.
void pop(void *Ptr, uint32_t Bytes);
private:
/// Compute the size of the storage space reserved for a thread.
uint32_t computeThreadStorageTotal() {
uint32_t NumLanesInBlock = mapping::getNumberOfThreadsInBlock();
return utils::align_down((state::SharedScratchpadSize / NumLanesInBlock),
allocator::ALIGNMENT);
}
/// Return the top address of the warp data stack, that is the first address
/// this warp will allocate memory at next.
void *getThreadDataTop(uint32_t TId) {
return &Data[computeThreadStorageTotal() * TId + Usage[TId]];
}
/// The actual storage, shared among all warps.
[[gnu::aligned(
allocator::ALIGNMENT)]] unsigned char Data[state::SharedScratchpadSize];
[[gnu::aligned(
allocator::ALIGNMENT)]] unsigned char Usage[mapping::MaxThreadsPerTeam];
};
static_assert(state::SharedScratchpadSize / mapping::MaxThreadsPerTeam <= 256,
"Shared scratchpad of this size not supported yet.");
/// The allocation of a single shared memory scratchpad.
static SharedMemorySmartStackTy SHARED(SharedMemorySmartStack);
void SharedMemorySmartStackTy::init(bool IsSPMD) {
Usage[mapping::getThreadIdInBlock()] = 0;
}
void *SharedMemorySmartStackTy::push(uint64_t Bytes) {
// First align the number of requested bytes.
/// FIXME: The stack shouldn't require worst-case padding. Alignment needs to
/// be passed in as an argument and the stack rewritten to support it.
uint64_t AlignedBytes = utils::align_up(Bytes, allocator::ALIGNMENT);
uint32_t StorageTotal = computeThreadStorageTotal();
// The main thread in generic mode gets the space of its entire warp as the
// other threads do not participate in any computation at all.
if (mapping::isMainThreadInGenericMode())
StorageTotal *= mapping::getWarpSize();
int TId = mapping::getThreadIdInBlock();
if (Usage[TId] + AlignedBytes <= StorageTotal) {
void *Ptr = getThreadDataTop(TId);
Usage[TId] += AlignedBytes;
return Ptr;
}
if (config::isDebugMode(DeviceDebugKind::CommonIssues))
PRINT("Shared memory stack full, fallback to dynamic allocation of global "
"memory will negatively impact performance.\n");
void *GlobalMemory = memory::allocGlobal(
AlignedBytes, "Slow path shared memory allocation, insufficient "
"shared memory stack memory!");
ASSERT(GlobalMemory != nullptr, "nullptr returned by malloc!");
return GlobalMemory;
}
void SharedMemorySmartStackTy::pop(void *Ptr, uint32_t Bytes) {
uint64_t AlignedBytes = utils::align_up(Bytes, allocator::ALIGNMENT);
if (utils::isSharedMemPtr(Ptr)) {
int TId = mapping::getThreadIdInBlock();
Usage[TId] -= AlignedBytes;
return;
}
memory::freeGlobal(Ptr, "Slow path shared memory deallocation");
}
} // namespace
void *memory::getDynamicBuffer() { return DynamicSharedBuffer; }
void *memory::allocShared(uint64_t Bytes, const char *Reason) {
return SharedMemorySmartStack.push(Bytes);
}
void memory::freeShared(void *Ptr, uint64_t Bytes, const char *Reason) {
SharedMemorySmartStack.pop(Ptr, Bytes);
}
void *memory::allocGlobal(uint64_t Bytes, const char *Reason) {
void *Ptr = malloc(Bytes);
if (config::isDebugMode(DeviceDebugKind::CommonIssues) && Ptr == nullptr)
PRINT("nullptr returned by malloc!\n");
return Ptr;
}
void memory::freeGlobal(void *Ptr, const char *Reason) { free(Ptr); }
///}
bool state::ICVStateTy::operator==(const ICVStateTy &Other) const {
return (NThreadsVar == Other.NThreadsVar) & (LevelVar == Other.LevelVar) &
(ActiveLevelVar == Other.ActiveLevelVar) &
(MaxActiveLevelsVar == Other.MaxActiveLevelsVar) &
(RunSchedVar == Other.RunSchedVar) &
(RunSchedChunkVar == Other.RunSchedChunkVar);
}
void state::ICVStateTy::assertEqual(const ICVStateTy &Other) const {
ASSERT(NThreadsVar == Other.NThreadsVar, nullptr);
ASSERT(LevelVar == Other.LevelVar, nullptr);
ASSERT(ActiveLevelVar == Other.ActiveLevelVar, nullptr);
ASSERT(MaxActiveLevelsVar == Other.MaxActiveLevelsVar, nullptr);
ASSERT(RunSchedVar == Other.RunSchedVar, nullptr);
ASSERT(RunSchedChunkVar == Other.RunSchedChunkVar, nullptr);
}
void state::TeamStateTy::init(bool IsSPMD) {
ICVState.NThreadsVar = 0;
ICVState.LevelVar = 0;
ICVState.ActiveLevelVar = 0;
ICVState.Padding0Val = 0;
ICVState.MaxActiveLevelsVar = 1;
ICVState.RunSchedVar = omp_sched_static;
ICVState.RunSchedChunkVar = 1;
ParallelTeamSize = 1;
HasThreadState = false;
ParallelRegionFnVar = nullptr;
}
bool state::TeamStateTy::operator==(const TeamStateTy &Other) const {
return (ICVState == Other.ICVState) &
(HasThreadState == Other.HasThreadState) &
(ParallelTeamSize == Other.ParallelTeamSize);
}
void state::TeamStateTy::assertEqual(TeamStateTy &Other) const {
ICVState.assertEqual(Other.ICVState);
ASSERT(ParallelTeamSize == Other.ParallelTeamSize, nullptr);
ASSERT(HasThreadState == Other.HasThreadState, nullptr);
}
state::TeamStateTy SHARED(ompx::state::TeamState);
state::ThreadStateTy **SHARED(ompx::state::ThreadStates);
namespace {
int returnValIfLevelIsActive(int Level, int Val, int DefaultVal,
int OutOfBoundsVal = -1) {
if (Level == 0)
return DefaultVal;
int LevelVar = omp_get_level();
if (OMP_UNLIKELY(Level < 0 || Level > LevelVar))
return OutOfBoundsVal;
int ActiveLevel = icv::ActiveLevel;
if (OMP_UNLIKELY(Level != ActiveLevel))
return DefaultVal;
return Val;
}
} // namespace
void state::init(bool IsSPMD, KernelEnvironmentTy &KernelEnvironment,
KernelLaunchEnvironmentTy &KernelLaunchEnvironment) {
SharedMemorySmartStack.init(IsSPMD);
if (mapping::isInitialThreadInLevel0(IsSPMD)) {
TeamState.init(IsSPMD);
ThreadStates = nullptr;
KernelEnvironmentPtr = &KernelEnvironment;
KernelLaunchEnvironmentPtr = &KernelLaunchEnvironment;
}
}
KernelEnvironmentTy &state::getKernelEnvironment() {
return *KernelEnvironmentPtr;
}
KernelLaunchEnvironmentTy &state::getKernelLaunchEnvironment() {
return *KernelLaunchEnvironmentPtr;
}
void state::enterDataEnvironment(IdentTy *Ident) {
ASSERT(config::mayUseThreadStates(),
"Thread state modified while explicitly disabled!");
if (!config::mayUseThreadStates())
return;
unsigned TId = mapping::getThreadIdInBlock();
ThreadStateTy *NewThreadState = static_cast<ThreadStateTy *>(
memory::allocGlobal(sizeof(ThreadStateTy), "ThreadStates alloc"));
uintptr_t *ThreadStatesBitsPtr = reinterpret_cast<uintptr_t *>(&ThreadStates);
if (!atomic::load(ThreadStatesBitsPtr, atomic::seq_cst)) {
uint32_t Bytes =
sizeof(ThreadStates[0]) * mapping::getNumberOfThreadsInBlock();
void *ThreadStatesPtr =
memory::allocGlobal(Bytes, "Thread state array allocation");
memset(ThreadStatesPtr, 0, Bytes);
if (!atomic::cas(ThreadStatesBitsPtr, uintptr_t(0),
reinterpret_cast<uintptr_t>(ThreadStatesPtr),
atomic::seq_cst, atomic::seq_cst))
memory::freeGlobal(ThreadStatesPtr,
"Thread state array allocated multiple times");
ASSERT(atomic::load(ThreadStatesBitsPtr, atomic::seq_cst),
"Expected valid thread states bit!");
}
NewThreadState->init(ThreadStates[TId]);
TeamState.HasThreadState = true;
ThreadStates[TId] = NewThreadState;
}
void state::exitDataEnvironment() {
ASSERT(config::mayUseThreadStates(),
"Thread state modified while explicitly disabled!");
unsigned TId = mapping::getThreadIdInBlock();
resetStateForThread(TId);
}
void state::resetStateForThread(uint32_t TId) {
if (!config::mayUseThreadStates())
return;
if (OMP_LIKELY(!TeamState.HasThreadState || !ThreadStates[TId]))
return;
ThreadStateTy *PreviousThreadState = ThreadStates[TId]->PreviousThreadState;
memory::freeGlobal(ThreadStates[TId], "ThreadStates dealloc");
ThreadStates[TId] = PreviousThreadState;
}
void state::runAndCheckState(void(Func(void))) {
TeamStateTy OldTeamState = TeamState;
OldTeamState.assertEqual(TeamState);
Func();
OldTeamState.assertEqual(TeamState);
}
void state::assumeInitialState(bool IsSPMD) {
TeamStateTy InitialTeamState;
InitialTeamState.init(IsSPMD);
InitialTeamState.assertEqual(TeamState);
ASSERT(mapping::isSPMDMode() == IsSPMD, nullptr);
}
int state::getEffectivePTeamSize() {
int PTeamSize = state::ParallelTeamSize;
return PTeamSize ? PTeamSize : mapping::getMaxTeamThreads();
}
extern "C" {
void omp_set_dynamic(int V) {}
int omp_get_dynamic(void) { return 0; }
void omp_set_num_threads(int V) { icv::NThreads = V; }
int omp_get_max_threads(void) {
int NT = icv::NThreads;
return NT > 0 ? NT : mapping::getMaxTeamThreads();
}
int omp_get_level(void) {
int LevelVar = icv::Level;
ASSERT(LevelVar >= 0, nullptr);
return LevelVar;
}
int omp_get_active_level(void) { return !!icv::ActiveLevel; }
int omp_in_parallel(void) { return !!icv::ActiveLevel; }
void omp_get_schedule(omp_sched_t *ScheduleKind, int *ChunkSize) {
*ScheduleKind = static_cast<omp_sched_t>((int)icv::RunSched);
*ChunkSize = state::RunSchedChunk;
}
void omp_set_schedule(omp_sched_t ScheduleKind, int ChunkSize) {
icv::RunSched = (int)ScheduleKind;
state::RunSchedChunk = ChunkSize;
}
int omp_get_ancestor_thread_num(int Level) {
return returnValIfLevelIsActive(Level, mapping::getThreadIdInBlock(), 0);
}
int omp_get_thread_num(void) {
return omp_get_ancestor_thread_num(omp_get_level());
}
int omp_get_team_size(int Level) {
return returnValIfLevelIsActive(Level, state::getEffectivePTeamSize(), 1);
}
int omp_get_num_threads(void) {
return omp_get_level() != 1 ? 1 : state::getEffectivePTeamSize();
}
int omp_get_thread_limit(void) { return mapping::getMaxTeamThreads(); }
int omp_get_num_procs(void) { return mapping::getNumberOfProcessorElements(); }
void omp_set_nested(int) {}
int omp_get_nested(void) { return false; }
void omp_set_max_active_levels(int Levels) {
icv::MaxActiveLevels = Levels > 0 ? 1 : 0;
}
int omp_get_max_active_levels(void) { return icv::MaxActiveLevels; }
omp_proc_bind_t omp_get_proc_bind(void) { return omp_proc_bind_false; }
int omp_get_num_places(void) { return 0; }
int omp_get_place_num_procs(int) { return omp_get_num_procs(); }
void omp_get_place_proc_ids(int, int *) {
// TODO
}
int omp_get_place_num(void) { return 0; }
int omp_get_partition_num_places(void) { return 0; }
void omp_get_partition_place_nums(int *) {
// TODO
}
int omp_get_cancellation(void) { return 0; }
void omp_set_default_device(int) {}
int omp_get_default_device(void) { return -1; }
int omp_get_num_devices(void) { return config::getNumDevices(); }
int omp_get_device_num(void) { return config::getDeviceNum(); }
int omp_get_num_teams(void) { return mapping::getNumberOfBlocksInKernel(); }
int omp_get_team_num() { return mapping::getBlockIdInKernel(); }
int omp_get_initial_device(void) { return -1; }
int omp_is_initial_device(void) { return 0; }
}
extern "C" {
[[clang::noinline]] void *__kmpc_alloc_shared(uint64_t Bytes) {
return memory::allocShared(Bytes, "Frontend alloc shared");
}
[[clang::noinline]] void __kmpc_free_shared(void *Ptr, uint64_t Bytes) {
memory::freeShared(Ptr, Bytes, "Frontend free shared");
}
void *__kmpc_get_dynamic_shared() { return memory::getDynamicBuffer(); }
void *llvm_omp_target_dynamic_shared_alloc() {
return __kmpc_get_dynamic_shared();
}
void *llvm_omp_get_dynamic_shared() { return __kmpc_get_dynamic_shared(); }
/// Allocate storage in shared memory to communicate arguments from the main
/// thread to the workers in generic mode. If we exceed
/// NUM_SHARED_VARIABLES_IN_SHARED_MEM we will malloc space for communication.
constexpr uint64_t NUM_SHARED_VARIABLES_IN_SHARED_MEM = 64;
[[clang::loader_uninitialized]] static void
*SharedMemVariableSharingSpace[NUM_SHARED_VARIABLES_IN_SHARED_MEM];
#pragma omp allocate(SharedMemVariableSharingSpace) \
allocator(omp_pteam_mem_alloc)
[[clang::loader_uninitialized]] static void **SharedMemVariableSharingSpacePtr;
#pragma omp allocate(SharedMemVariableSharingSpacePtr) \
allocator(omp_pteam_mem_alloc)
void __kmpc_begin_sharing_variables(void ***GlobalArgs, uint64_t nArgs) {
if (nArgs <= NUM_SHARED_VARIABLES_IN_SHARED_MEM) {
SharedMemVariableSharingSpacePtr = &SharedMemVariableSharingSpace[0];
} else {
SharedMemVariableSharingSpacePtr = (void **)memory::allocGlobal(
nArgs * sizeof(void *), "new extended args");
ASSERT(SharedMemVariableSharingSpacePtr != nullptr,
"Nullptr returned by malloc!");
}
*GlobalArgs = SharedMemVariableSharingSpacePtr;
}
void __kmpc_end_sharing_variables() {
if (SharedMemVariableSharingSpacePtr != &SharedMemVariableSharingSpace[0])
memory::freeGlobal(SharedMemVariableSharingSpacePtr, "new extended args");
}
void __kmpc_get_shared_variables(void ***GlobalArgs) {
*GlobalArgs = SharedMemVariableSharingSpacePtr;
}
}
#pragma omp end declare target
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