Merge pull request #42683 from nouiz:upstream_master_grid_size

PiperOrigin-RevId: 335609206
Change-Id: Iad371a188dd774bf1293eb126921189a54f5ffba
This commit is contained in:
TensorFlower Gardener 2020-10-06 04:04:24 -07:00
commit b49b04b9cc
15 changed files with 125 additions and 22 deletions

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@ -31,9 +31,15 @@ ParallelLoopEmitter::ParallelLoopEmitter(
std::vector<llvm_ir::IrArray::Index>
ParallelLoopEmitter::EmitIndexAndSetExitBasicBlock(absl::string_view loop_name,
llvm::Type* index_type) {
llvm::Type* index_type,
llvm::Value* base_index) {
CHECK_NE(index_type, nullptr);
CHECK_EQ(base_index, nullptr)
<< "XLA CPU implementation of"
<< " ParallelLoopEmitter::EmitIndexAndSetExitBasicBlock doesn't support"
<< " base_index, but it was requested.";
CHECK(!shape_.IsTuple());
CHECK(!ShapeUtil::IsScalar(shape_));

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@ -61,7 +61,8 @@ class ParallelLoopEmitter : public llvm_ir::LoopEmitter {
~ParallelLoopEmitter() override = default;
std::vector<llvm_ir::IrArray::Index> EmitIndexAndSetExitBasicBlock(
absl::string_view loop_name, llvm::Type* index_type) override;
absl::string_view loop_name, llvm::Type* index_type,
llvm::Value* base_index) override;
private:
const DynamicLoopBounds* dynamic_loop_bounds_;

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@ -323,6 +323,7 @@ cc_library(
"//tensorflow/compiler/xla:shape_util",
"//tensorflow/compiler/xla:xla_data_proto_cc",
"//tensorflow/compiler/xla/service/llvm_ir:ir_array",
"//tensorflow/compiler/xla/service/llvm_ir:kernel_support_library",
"//tensorflow/compiler/xla/service/llvm_ir:llvm_loop",
"//tensorflow/compiler/xla/service/llvm_ir:llvm_util",
"//tensorflow/compiler/xla/service/llvm_ir:loop_emitter",

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@ -610,6 +610,11 @@ static StatusOr<bool> DeviceCompare(se::Stream* stream,
executor->GetDeviceDescription().threads_per_block_limit();
gpu_device_info.threads_per_warp =
executor->GetDeviceDescription().threads_per_warp();
gpu_device_info.shared_memory_per_block =
executor->GetDeviceDescription().shared_memory_per_block();
gpu_device_info.threads_per_core_limit =
executor->GetDeviceDescription().threads_per_core_limit();
gpu_device_info.core_count = executor->GetDeviceDescription().core_count();
LaunchDimensions dim =
CalculateLaunchDimensions(buffer_shape, gpu_device_info);

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@ -617,6 +617,9 @@ StatusOr<std::unique_ptr<Executable>> GpuCompiler::RunBackend(
stream_exec->GetDeviceDescription().threads_per_warp();
gpu_device_info.shared_memory_per_block =
stream_exec->GetDeviceDescription().shared_memory_per_block();
gpu_device_info.threads_per_core_limit =
stream_exec->GetDeviceDescription().threads_per_core_limit();
gpu_device_info.core_count = stream_exec->GetDeviceDescription().core_count();
absl::optional<CudaComputeCapability> cuda_compute_capability =
[&]() -> absl::optional<CudaComputeCapability> {

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@ -32,6 +32,8 @@ struct GpuDeviceInfo {
int threads_per_block_limit;
int threads_per_warp;
int shared_memory_per_block;
int threads_per_core_limit;
int core_count;
};
} // namespace gpu
} // namespace xla

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@ -2303,7 +2303,7 @@ StatusOr<std::unique_ptr<Thunk>> IrEmitterUnnested::BuildConditionalThunk(
Status IrEmitterUnnested::EmitTargetElementLoopInThunk(
const HloInstruction& hlo,
const llvm_ir::ElementGenerator& element_generator, KernelThunk* thunk,
int unroll_factor) {
int unroll_factor, bool few_waves) {
VLOG(3) << bindings_.ToString();
bool multi_output = hlo.shape().IsTuple();
@ -2314,7 +2314,8 @@ Status IrEmitterUnnested::EmitTargetElementLoopInThunk(
<< ShapeUtil::HumanStringWithLayout(hlo.shape())
<< " for unroll_factor " << unroll_factor;
LaunchDimensions launch_dimensions = CalculateLaunchDimensions(
element_shape, ir_emitter_context_->gpu_device_info(), unroll_factor);
element_shape, ir_emitter_context_->gpu_device_info(), unroll_factor,
few_waves);
UpdateLaunchDimensions(launch_dimensions, thunk,
ir_emitter_context_->llvm_module());
if (!multi_output) {
@ -2400,8 +2401,27 @@ Status IrEmitterUnnested::EmitTargetElementLoop(
std::unique_ptr<KernelThunk> kernel_thunk =
BuildKernelThunk(&hlo, /*implements_whole_instruction=*/true);
// Check if we want to schedule grid size that has fewer SM waves.
// This speed up computations in some cases.
bool few_waves = false;
auto few_waves_allow_instr = [](const HloInstruction* instr) {
return instr->IsElementwise() || instr->opcode() == HloOpcode::kParameter ||
// We need to make the codegen broadcast aware before enabling
// more broadcast pattern.
(instr->opcode() == HloOpcode::kBroadcast &&
instr->dimensions().empty());
};
if (hlo.opcode() == HloOpcode::kFusion) {
few_waves =
absl::c_all_of(hlo.fused_instructions_computation()->instructions(),
few_waves_allow_instr);
} else {
few_waves = few_waves_allow_instr(&hlo);
}
Status emit_status = EmitTargetElementLoopInThunk(
hlo, body_emitter, kernel_thunk.get(), unroll_factor);
hlo, body_emitter, kernel_thunk.get(), unroll_factor, few_waves);
thunk_sequence_.emplace_back(std::move(kernel_thunk));
return emit_status;

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@ -178,7 +178,7 @@ class IrEmitterUnnested : public IrEmitter,
// `unroll_factor` is greater than one.
Status EmitTargetElementLoopInThunk(
const HloInstruction& hlo, const llvm_ir::ElementGenerator& body_emitter,
KernelThunk* thunk, int unroll_factor);
KernelThunk* thunk, int unroll_factor, bool few_waves = false);
Status Postprocess(HloInstruction* hlo) override;

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@ -56,7 +56,7 @@ static int64 ThreadsPerBlockLimit(GpuDeviceInfo gpu_device_info) {
// Calculates the launch dimensions used to invoke `hlo`.
LaunchDimensions CalculateLaunchDimensions(const Shape& shape,
GpuDeviceInfo gpu_device_info,
int unroll_factor) {
int unroll_factor, bool few_waves) {
int64 num_elements = ShapeUtil::ElementsIn(shape);
if (num_elements <= 1) {
return LaunchDimensions();
@ -90,6 +90,11 @@ LaunchDimensions CalculateLaunchDimensions(const Shape& shape,
}
int64 block_count = CeilOfRatio(num_elements, threads_per_block);
if (few_waves) {
threads_per_block = std::min(threads_per_block, int64{128});
block_count = gpu_device_info.core_count *
(gpu_device_info.threads_per_core_limit / threads_per_block);
}
VLOG(2) << absl::StrFormat(
"Initialized the block count to ceil(# of elements / threads per "
"block) = ceil(%d/%d) = %d",

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@ -67,7 +67,8 @@ std::ostream& operator<<(std::ostream& out,
LaunchDimensions CalculateLaunchDimensions(const Shape& shape,
GpuDeviceInfo gpu_device_info,
int unroll_factor = 1);
int unroll_factor = 1,
bool few_waves = false);
} // namespace gpu
} // namespace xla

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@ -23,6 +23,7 @@ limitations under the License.
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Value.h"
#include "tensorflow/compiler/xla/service/gpu/target_util.h"
#include "tensorflow/compiler/xla/service/llvm_ir/kernel_support_library.h"
#include "tensorflow/compiler/xla/service/llvm_ir/llvm_loop.h"
#include "tensorflow/compiler/xla/service/llvm_ir/llvm_util.h"
#include "tensorflow/compiler/xla/shape_util.h"
@ -58,7 +59,8 @@ ParallelLoopEmitter::ParallelLoopEmitter(
std::vector<llvm_ir::IrArray::Index>
ParallelLoopEmitter::EmitIndexAndSetExitBasicBlock(absl::string_view loop_name,
llvm::Type* index_type) {
llvm::Type* index_type,
llvm::Value* base_index) {
// Emit the following code in LLVM IR:
// linear_index = blockIdx.x * blockDim.x + threadIdx.x;
// if (linear_index < num_elements) {
@ -122,6 +124,12 @@ ParallelLoopEmitter::EmitIndexAndSetExitBasicBlock(absl::string_view loop_name,
"linear_index_base", /*HasNUW=*/true, /*HasNSW=*/true);
}
if (base_index != nullptr) {
linear_index_base =
b_->CreateAdd(linear_index_base, base_index, "linear_index_plus_base",
/*HasNUW=*/true, /*HasNSW=*/true);
}
array_indices.emplace_back(linear_index_base, shape_, b_);
for (int i = 1; i < unroll_factor_; ++i) {
llvm::Value* linear_index =
@ -147,5 +155,43 @@ ParallelLoopEmitter::EmitIndexAndSetExitBasicBlock(absl::string_view loop_name,
return array_indices;
}
Status ParallelLoopEmitter::EmitLoop(absl::string_view loop_name,
llvm::Type* index_type) {
if (index_type == nullptr) {
index_type = b_->getInt64Ty();
}
int64 total_threads = launch_dimensions_.launch_bound();
int64 num_elements = ShapeUtil::ElementsIn(shape_);
// If all the elements are handled by the current threads, no need
// to add a loop inside the kernel.
if (total_threads * unroll_factor_ >= num_elements) {
VLOG(1) << "ParallelLoopEmitter::EmitLoop fallback";
return LoopEmitter::EmitLoop(loop_name, index_type);
}
KernelSupportLibrary ksl(b_, llvm_ir::UnrollMode::kDefaultUnroll);
auto constant = [&](int64 val) {
return llvm::ConstantInt::get(index_type, val);
};
TF_RETURN_IF_ERROR(ksl.ForWithStatus(
"loop", constant(0), constant(num_elements),
constant(total_threads * unroll_factor_), [&](llvm::Value* base_indvar) {
for (const llvm_ir::IrArray::Index& array_index :
EmitIndexAndSetExitBasicBlock(loop_name, index_type,
base_indvar)) {
TF_RETURN_IF_ERROR(body_emitter_(array_index));
}
return Status::OK();
}));
// Set the insertion point of b_ to the loop exit, so that
// code emitted for later instructions will be correctly placed.
if (exit_bb_ != nullptr) {
b_->SetInsertPoint(exit_bb_);
}
return Status::OK();
}
} // namespace gpu
} // namespace xla

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@ -57,7 +57,11 @@ class ParallelLoopEmitter : public llvm_ir::LoopEmitter {
~ParallelLoopEmitter() override = default;
std::vector<llvm_ir::IrArray::Index> EmitIndexAndSetExitBasicBlock(
absl::string_view loop_name, llvm::Type* index_type) override;
absl::string_view loop_name, llvm::Type* index_type,
llvm::Value* base_index) override;
Status EmitLoop(absl::string_view loop_name = "",
llvm::Type* index_type = nullptr);
private:
// The thread and block dimension to parallelize the loop on.

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@ -148,8 +148,8 @@ TEST_F(GpuUnrollingTest, DisabledUnrollUnfusedSine) {
HloModule test_module
ENTRY SineFunc {
p0 = f32[160000]{0} parameter(0)
ROOT s = f32[160000]{0} sine(p0)
p0 = f32[1600000]{0} parameter(0)
ROOT s = f32[1600000]{0} sine(p0)
})";
auto hlo_module =
ParseAndReturnVerifiedModule(kUnfusedAddModule, config).ValueOrDie();
@ -182,8 +182,8 @@ TEST_F(GpuUnrollingTest, DisabledUnrollUnfusedCosine) {
HloModule test_module
ENTRY SineFunc {
p0 = f32[160000]{0} parameter(0)
ROOT s = f32[160000]{0} cosine(p0)
p0 = f32[1600000]{0} parameter(0)
ROOT s = f32[1600000]{0} cosine(p0)
})";
auto hlo_module =
ParseAndReturnVerifiedModule(kUnfusedAddModule, config).ValueOrDie();
@ -216,8 +216,8 @@ TEST_F(GpuUnrollingTest, DisabledUnrollUnfusedPower) {
HloModule test_module
ENTRY SineFunc {
p0 = f32[160000]{0} parameter(0)
ROOT s = f32[160000]{0} power(p0, p0)
p0 = f32[1600000]{0} parameter(0)
ROOT s = f32[1600000]{0} power(p0, p0)
})";
auto hlo_module =
ParseAndReturnVerifiedModule(kUnfusedAddModule, config).ValueOrDie();
@ -241,8 +241,8 @@ TEST_F(GpuUnrollingTest, DisabledUnrollUnfusedAtan2) {
HloModule test_module
ENTRY SineFunc {
p0 = f32[160000]{0} parameter(0)
ROOT s = f32[160000]{0} atan2(p0, p0)
p0 = f32[1600000]{0} parameter(0)
ROOT s = f32[1600000]{0} atan2(p0, p0)
})";
auto hlo_module =
ParseAndReturnVerifiedModule(kUnfusedAddModule, config).ValueOrDie();

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@ -130,8 +130,14 @@ IrArray::Index LoopEmitter::EmitDynamicIndex(ForLoopNest* loop_nest,
}
std::vector<IrArray::Index> LoopEmitter::EmitIndexAndSetExitBasicBlock(
absl::string_view loop_name, llvm::Type* index_type) {
absl::string_view loop_name, llvm::Type* index_type,
llvm::Value* base_index) {
CHECK_NE(index_type, nullptr);
CHECK_EQ(base_index, nullptr)
<< "XLA CPU implementation of"
<< " LoopEmitter::EmitIndexAndSetExitBasicBlock doesn't support"
<< " base_index, but it was requested.";
if (ShapeUtil::IsScalar(shape_)) {
// No loop needed, so set exit_bb_ to nullptr.
exit_bb_ = nullptr;
@ -164,7 +170,8 @@ Status LoopEmitter::EmitLoop(absl::string_view loop_name,
}
for (const IrArray::Index& array_index :
EmitIndexAndSetExitBasicBlock(loop_name, index_type)) {
EmitIndexAndSetExitBasicBlock(loop_name, index_type,
/*base_index*/ nullptr)) {
TF_RETURN_IF_ERROR(body_emitter_(array_index));
}

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@ -71,11 +71,13 @@ class LoopEmitter {
// specifies the element, will return multiple indices if the loop is
// unrolled.
std::vector<IrArray::Index> EmitIndexAndSetExitBasicBlock() {
return EmitIndexAndSetExitBasicBlock(/*loop_name=*/"", b_->getInt64Ty());
return EmitIndexAndSetExitBasicBlock(/*loop_name=*/"", b_->getInt64Ty(),
/*base_index*/ nullptr);
}
virtual std::vector<IrArray::Index> EmitIndexAndSetExitBasicBlock(
absl::string_view loop_name, llvm::Type* index_type);
absl::string_view loop_name, llvm::Type* index_type,
llvm::Value* base_index);
// Emits a complete loop nest for every element in the given shape.
Status EmitLoop(absl::string_view loop_name = "",