[FRONTEND] Significantly reduce kernel launch time (#367)

This commit is contained in:
Philippe Tillet
2021-11-04 13:25:24 -07:00
committed by GitHub
parent 2acaa4d0dd
commit 5d54352164
4 changed files with 245 additions and 124 deletions

View File

@@ -13,6 +13,7 @@
#include <pybind11/functional.h>
#include <pybind11/pybind11.h>
#include <pybind11/stl.h>
#include "Python.h"
#include <regex>
#include <string>
#include "llvm/IR/Module.h"
@@ -23,6 +24,7 @@ namespace py = pybind11;
namespace ir = triton::ir;
namespace drv = triton::driver;
/*****************************************************************************/
/* Python bindings for triton::driver */
/*****************************************************************************/
@@ -99,8 +101,113 @@ void hip_enqueue(uint64_t stream, uint64_t kernel,
}
std::string pow2_divisor(long N){
if(N % 16 == 0) return "16";
if(N % 8 == 0) return "8";
if(N % 4 == 0) return "4";
if(N % 2 == 0) return "2";
return "1";
}
// Launch
void parse_args(py::handle& args, const std::string& func_key, py::handle& arg_names,
std::string& cache_key, std::string& params, size_t& params_size, PyObject* constants,
int num_warps, int num_stages) {
size_t len = PyList_Size(args.ptr());
params.reserve(8*len); // 8 max bytes by argument
char* params_ptr = &params[0];
cache_key = func_key;
for(int i = 0; i < len; i++){
auto arg_ptr = PyList_GetItem(args.ptr(), i);
auto arg = py::handle(arg_ptr);
// argument is `long`
if(PyLong_Check(arg_ptr)){
int overflow;
long long value = PyLong_AsLongLongAndOverflow(arg_ptr, &overflow);
// long and int have different kernels
if(!overflow & (std::abs(value) <= 0xffffffff)){
cache_key += 'I';
params_ptr = (char*)(((uintptr_t)params_ptr + 3) & (-4));
std::memcpy(params_ptr, &value, 4);
params_ptr += 4;
}
else{
cache_key += 'L';
params_ptr = (char*)(((uintptr_t)params_ptr + 7) & (-8));
if(overflow){
unsigned long long uvalue = PyLong_AsUnsignedLongLong(arg_ptr);
std::memcpy(&value, &uvalue, 8);
}
std::memcpy(params_ptr, &value, 8);
params_ptr += 8;
}
// values equal to 1 are specialized
if(value == 1)
cache_key += '1';
else
cache_key += 'x';
// values divisible by small powers of 2 are specialized
cache_key += pow2_divisor(value);
continue;
}
// argument is `float`
if(PyFloat_Check(arg_ptr)){
cache_key += "f";
float value = PyFloat_AsDouble(arg_ptr);
params_ptr = (char*)(((uintptr_t)params_ptr + 3) & (-4));
std::memcpy(params_ptr, &value, 4);
params_ptr += 4;
continue;
}
// argument is `bool`
if(PyBool_Check(arg_ptr)){
cache_key += "B";
bool value = arg_ptr == Py_True ? true : false;
std::memcpy(params_ptr, &value, 1);
params_ptr += 1;
continue;
}
// argument is tensor
PyObject* data_ptr = PyObject_CallMethod(arg_ptr, "data_ptr", nullptr);
if(data_ptr){
cache_key += "P";
long value = PyLong_AsLong(data_ptr);
params_ptr = (char*)(((uintptr_t)params_ptr + 7) & (-8));
std::memcpy(params_ptr, &value, 8);
params_ptr += 8;
PyObject* dtype = PyObject_GetAttrString(arg_ptr, "dtype");
PyObject* repr = PyObject_Repr(dtype);
const char* start = (const char*)PyUnicode_1BYTE_DATA(repr) + 6; // remove 'torch.'
size_t len = PyUnicode_GET_LENGTH(repr) - 6;
cache_key += std::string(start, len);
continue;
}
// argument is `constexpr`
PyObject* value = PyObject_GetAttrString(arg_ptr, "value");
if(value){
PyObject* name = PyList_GetItem(arg_names.ptr(), i);
PyDict_SetItem(constants, name, value);
PyObject* repr = PyObject_Repr(value);
const char* start = (const char*)PyUnicode_1BYTE_DATA(repr);
size_t len = PyUnicode_GET_LENGTH(repr);
cache_key += std::string(start, len);
continue;
}
assert(false);
}
cache_key += std::to_string(num_warps);
cache_key += std::to_string(num_stages);
params_size = (std::ptrdiff_t)(params_ptr - &params[0]);
}
//
void init_triton_runtime(py::module &&m) {
// m.def("current_stream", [](uint64_t device){
// return (uint64_t)(c10::cuda::getCurrentCUDAStream(device).stream());
// });
// wrap backend_t
py::enum_<backend_t>(m, "backend")
.value("HOST", HOST)
@@ -116,6 +223,51 @@ void init_triton_runtime(py::module &&m) {
}
);
// cache key
m.def("launch", [](py::handle args, const std::string& func_key, py::list& arg_names,
py::handle device, py::handle stream, py::handle bin_cache, py::handle num_warps, py::handle num_stages,
py::handle add_to_cache, py::handle grid){
// parse arguments to compute cache key, compile-time constants and packed kernel arguments
long _num_warps = PyLong_AsLong(num_warps.ptr());
long _num_stages = PyLong_AsLong(num_stages.ptr());
std::string cache_key;
std::string params;
size_t params_size;
PyObject* constants = PyDict_New();
parse_args(args, func_key, arg_names, cache_key, params, params_size, constants, _num_warps, _num_stages);
// get cached binary
PyObject* key = PyUnicode_FromString(cache_key.c_str());
PyObject* bin = nullptr;
if(!PyDict_Contains(bin_cache.ptr(), key)){
add_to_cache(py::handle(key), args, device, num_warps, num_stages);
}
bin = PyDict_GetItem(bin_cache.ptr(), key);
// get grid
PyObject* grid_ptr = grid.ptr();
if(!PySequence_Check(grid_ptr)){
PyObject* grid_call = PyObject_GetAttrString(grid_ptr, "__call__");
grid_ptr = PyObject_Call(grid_call, PyTuple_Pack(1, constants), nullptr);
}
int size = PySequence_Size(grid_ptr);
int grid_0 = PyLong_AsLong(PySequence_GetItem(grid_ptr, 0));
int grid_1 = size < 2 ? 1 : PyLong_AsLong(PySequence_GetItem(grid_ptr, 1));
int grid_2 = size < 3 ? 1 : PyLong_AsLong(PySequence_GetItem(grid_ptr, 2));
// enqueue
uint64_t kernel = PyLong_AsLong(PyObject_GetAttrString(bin, "kernel"));
uint64_t shared_mem = PyLong_AsLong(PyObject_GetAttrString(bin, "shared_mem"));
// actually launch
void *config[] = {
CU_LAUNCH_PARAM_BUFFER_POINTER, params.data(),
CU_LAUNCH_PARAM_BUFFER_SIZE, &params_size,
CU_LAUNCH_PARAM_END
};
uint64_t _stream = PyLong_AsLong(stream.ptr());
drv::dispatch::cuLaunchKernel((CUfunction)kernel, grid_0, grid_1, grid_2,
_num_warps*32, 1, 1, shared_mem, (CUstream)_stream,
nullptr, config);
return py::handle(bin);
});
// query maximum shared memory
m.def("max_shared_memory", [](backend_t backend, uint64_t device) {
if (backend == HOST)