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triton/lib/codegen/analysis/layout.cc

364 lines
12 KiB
C++

#include <algorithm>
#include <iostream>
#include <numeric>
#include "triton/codegen/analysis/axes.h"
#include "triton/codegen/analysis/align.h"
#include "triton/codegen/analysis/layout.h"
#include "triton/codegen/instructions.h"
#include "triton/ir/function.h"
#include "triton/ir/module.h"
#include "triton/ir/utils.h"
namespace triton{
namespace codegen{
namespace analysis{
// constructor
layout::layout(analysis::axes *axes, analysis::align *align, size_t num_warps)
: axes_(axes), align_(align), num_warps_(num_warps) { }
// get group id
unsigned layout::layout_of(ir::value *value) const
{ return groups_.at(value); }
// get values
const std::vector<ir::value*>& layout::values_of(unsigned id) const
{ return values_.at(id); }
// get number of groups
size_t layout::num_layouts() const
{ return values_.size(); }
// connect two values
void layout::connect(ir::value *x, ir::value *y) {
if(x == y)
return;
if(!x->get_type()->is_tile_ty())
return;
if(!y->get_type()->is_tile_ty())
return;
std::vector<int> x_axes = axes_->get(x);
std::vector<int> y_axes = axes_->get(y);
std::set<int> sx_axes(x_axes.begin(), x_axes.end());
std::set<int> sy_axes(y_axes.begin(), y_axes.end());
std::set<int> common;
std::set_intersection(sx_axes.begin(), sx_axes.end(),
sy_axes.begin(), sy_axes.end(),
std::inserter(common, common.begin()));
graph_.add_edge(x, x);
graph_.add_edge(y, y);
if(!common.empty())
graph_.add_edge(x, y);
}
// make graph
void layout::make_graph(ir::instruction *i) {
for(ir::value* opx: i->ops())
for(ir::value* opy: i->ops()){
connect(i, opx);
connect(opx, opy);
}
}
// hmma
bool is_hmma_c(ir::value *v){
bool result = false;
if(auto *x = dynamic_cast<ir::dot_inst*>(v)){
ir::value *a = x->get_operand(0);
ir::type *a_ty = a->get_type();
ir::value *b = x->get_operand(1);
ir::type *b_ty = b->get_type();
result = a_ty->get_scalar_ty()->is_half_ty() &&
b_ty->get_scalar_ty()->is_half_ty();
}
return result;
}
const layout_t* layout::get(ir::value *v) const {
return layouts_.at(groups_.at(v));
}
std::map<size_t, layout_t*>& layout::get_all() {
return layouts_;
}
void extract_io_use(ir::value *v, std::set<ir::value*>& result) {
for(ir::user* u: v->get_users()){
auto i = dynamic_cast<ir::io_inst*>(u);
if(i && i->get_pointer_operand() == v)
result.insert(v);
}
}
void extract_dot_use(ir::value *v, ir::value*& result, size_t n) {
for(ir::user* u: v->get_users()){
auto i = dynamic_cast<ir::dot_inst*>(u);
if(i && i->get_operand(n) == v)
result = v;
}
}
void extract_hmma_dot_use(ir::value *v, ir::value*& result, size_t n) {
for(ir::user* u: v->get_users()){
auto i = dynamic_cast<ir::dot_inst*>(u);
if(i && is_hmma_c(i) && i->get_operand(n) == v)
result = v;
}
}
inline bool is_trans(ir::value *v) {
if(dynamic_cast<ir::trans_inst *>(v)) {
return true;
}
if(auto *phi = dynamic_cast<ir::instruction *>(v)) {
bool result = true;
for(ir::value *op: phi->ops())
result = result && is_trans(op);
return result;
}
return false;
}
layout_t::layout_t(layout_type_t _type,
const std::vector<int> &_axes,
const std::vector<unsigned> &_shapes,
const std::vector<ir::value *> &_values, ir::type *_ty,
size_t _id,
analysis::align* align): type(_type), axes(_axes), shapes(_shapes), values(_values), id(_id), ty(_ty) {
// io pointer
std::set<ir::value*> ptr;
for(ir::value* v: values)
extract_io_use(v, ptr);
order.resize(axes.size());
std::iota(order.begin(), order.end(), 0);
for(ir::value *v: ptr){
auto max_contiguous = align->contiguous(v);
std::sort(order.begin(), order.end(), [&](unsigned a, unsigned b) {
return max_contiguous[a] > max_contiguous[b];
});
}
}
inline unsigned clamp(unsigned x, unsigned lo, unsigned hi) {
return std::min(std::max(x, lo), hi);
}
layout_hmma_884_t::layout_hmma_884_t(size_t num_warps,
const std::vector<int>& _axes,
const std::vector<unsigned>& _shapes,
const std::vector<ir::value *> &values, ir::type *_ty, size_t _id,
analysis::align* align): layout_t(HMMA_884, _axes, _shapes, values, _ty, _id, align) {
unsigned shape_0 = shapes[order[0]];
unsigned shape_1 = shapes[order[1]];
/* fragments per warp */
// try to make things as square as possible to maximize data re-use
fpw = {1, 1, 1};
std::vector<int> fpw_nm1;
unsigned num_fragments = std::min<unsigned>((shape_0/8)*(shape_1/8), 4);
do {
fpw_nm1 = fpw;
if(fpw[0]*fpw[1] < num_fragments)
fpw[0] = clamp(fpw[0]*2, 1, shape_0 / 8);
if(fpw[0]*fpw[1] < num_fragments)
fpw[1] = clamp(fpw[1]*2, 1, shape_1 / 8);
}while(fpw_nm1 != fpw);
/* warps per tile */
// try to make things as square as possible to maximize data re-use
wpt = {1, 1, 1};
std::vector<int> wpt_nm1;
do{
wpt_nm1 = wpt;
if(wpt[0] * wpt[1] * wpt[2] < num_warps)
wpt[0] = clamp(wpt[0]*2, 1, shape_0 / (fpw[0]*8));
if(wpt[0] * wpt[1] * wpt[2] < num_warps)
wpt[1] = clamp(wpt[1]*2, 1, shape_1 / (fpw[1]*8));
}while(wpt_nm1 != wpt);
/* sanity check */
unsigned effective_num_warps = 1;
for(size_t d = 0; d < shapes.size(); d++)
effective_num_warps *= wpt[d];
if(num_warps != effective_num_warps)
throw std::runtime_error("cannot create a kernel with this amount of warps");
}
layout_scanline_t::layout_scanline_t(size_t num_warps,
const std::vector<int>& _axes,
const std::vector<unsigned>& _shapes,
const std::vector<ir::value *> &values, ir::type *_ty,
size_t _id,
analysis::align* align): layout_t(SCANLINE, _axes, _shapes, values, _ty, _id, align){
unsigned size = std::accumulate(shapes.begin(), shapes.end(), 1, std::multiplies<int>());
unsigned num_threads = num_warps * 32;
nts.resize(shapes.size());
mts.resize(shapes.size());
unsigned i = order[0];
nts[i] = clamp(size / num_threads, 1, 4);
mts[i] = clamp(num_threads, 1, shapes[i] / nts[i]);
num_threads = num_threads / mts[i];
for(size_t d = 1; d < shapes.size(); d++){
i = order[d];
nts[i] = 1;
mts[i] = clamp(num_threads, 1, shapes[i]);
num_threads = num_threads / mts[i];
}
/* sanity check */
unsigned effective_num_threads = 1;
for(size_t d = 0; d < shapes.size(); d++)
effective_num_threads *= mts[d];
if(num_warps * 32 != effective_num_threads)
throw std::runtime_error("cannot create a kernel with this amount of warps");
}
inline bool is_loop_latch(ir::phi_node *phi, ir::instruction *terminator){
if(phi->get_parent() != terminator->get_parent())
return false;
if(auto *br = dynamic_cast<ir::cond_branch_inst*>(terminator))
return br->get_true_dest() == phi->get_parent()
|| br->get_false_dest() == phi->get_parent();
else if(dynamic_cast<ir::uncond_branch_inst*>(terminator))
return false;
else
throw std::runtime_error("unreachable");
}
void extract_double_bufferable(ir::value *v, std::shared_ptr<double_buffer_info_t>& res) {
auto* phi = dynamic_cast<ir::phi_node*>(v);
if(!phi || phi->get_num_incoming() != 2)
return;
ir::basic_block *block_0 = phi->get_incoming_block(0);
ir::basic_block *block_1 = phi->get_incoming_block(1);
ir::instruction *terminator_0 = block_0->get_inst_list().back();
ir::instruction *terminator_1 = block_1->get_inst_list().back();
bool is_latch_0 = is_loop_latch(phi, terminator_0);
bool is_latch_1 = is_loop_latch(phi, terminator_1);
ir::value *value_0 = phi->get_incoming_value(0);
ir::value *value_1 = phi->get_incoming_value(1);
ir::instruction *i_0 = dynamic_cast<ir::instruction*>(value_0);
ir::instruction *i_1 = dynamic_cast<ir::instruction*>(value_1);
if(!i_0 || !i_1 ||
storage_info.at(i_0->get_id()).first != codegen::SHARED ||
storage_info.at(i_1->get_id()).first != codegen::SHARED)
return;
if(is_latch_1)
res.reset(new double_buffer_info_t{value_0, value_1, phi});
if(is_latch_0)
res.reset(new double_buffer_info_t{value_1, value_0, phi});
}
layout_shared_t::layout_shared_t(const layout_t *arg,
const std::vector<int>& _axes,
const std::vector<unsigned>& _shapes,
const std::vector<ir::value *> &values,
ir::type *ty,
size_t _id,
analysis::align* align): layout_t(SHARED, _axes, _shapes, values, ty, _id, align) {
size = 0;
// double-buffering
for(ir::value *v: values)
extract_double_bufferable(v, double_buffer);
// order
if(arg->type == SCANLINE)
order = arg->order;
ir::value* dot_a = nullptr;
ir::value* dot_b = nullptr;
ir::value* hmma_dot_a = nullptr;
ir::value* hmma_dot_b = nullptr;
for(ir::value* v: values){
extract_dot_use(v, dot_a, 0);
extract_dot_use(v, dot_b, 1);
extract_hmma_dot_use(v, hmma_dot_a, 0);
extract_hmma_dot_use(v, hmma_dot_b, 1);
}
std::vector<int> col = {0, 1};
std::vector<int> row = {1, 0};
bool is_nonhmma_dot_a = dot_a && !hmma_dot_a;
bool is_nonhmma_dot_b = dot_b && !hmma_dot_b;
if(is_nonhmma_dot_a)
order = is_trans(dot_a) ? row : col;
if(is_nonhmma_dot_b)
order = is_trans(dot_b) ? col : row;
// padding
pad = 0;
if(hmma_dot_a){
bool row = is_trans(hmma_dot_a) ^ order[0] == 1;
pad = 24 - shapes[row ? 0: 1] % 32;
}
else if(hmma_dot_b){
bool row = is_trans(hmma_dot_b) ^ order[0] == 1;
pad = 24 - shapes[row ? 1 : 0] % 32;
}
else if(order != arg->order) {
pad = 4;
}
// size
auto shape = this->shapes;
shape[order[0]] += pad;
size = ty->get_primitive_size_in_bits() / 8;
for(auto s: shape)
size *= s;
if(double_buffer)
size *= 2;
}
// layout factory method
void layout::create(size_t id, const std::vector<ir::value*>& values) {
auto it_hmma_c = std::find_if(values.begin(), values.end(), &is_hmma_c);
auto cmp = [](ir::value* x, ir::value *y) {
return x->get_type()->get_tile_ranks1() <
y->get_type()->get_tile_ranks1();
};
ir::value *largest = *std::max_element(values.begin(), values.end(), cmp);
const auto& axes = axes_->get(largest);
const auto& shapes = largest->get_type()->get_tile_shapes();
auto it_cts = std::find_if(values.begin(), values.end(), [](ir::value* v) {
return dynamic_cast<ir::copy_to_shared_inst*>(v);
});
// type
if(it_hmma_c != values.end())
layouts_[id] = new layout_hmma_884_t(num_warps_, axes, shapes, values, largest->get_type()->get_scalar_ty(), id, align_);
else if(it_cts != values.end()){
ir::copy_to_shared_inst *cts = (ir::copy_to_shared_inst*)*it_cts;
ir::value *arg = cts->get_operand(0);
create(groups_.at(arg), values_.at(groups_.at(arg)));
layouts_[id] = new layout_shared_t(get(arg), axes, shapes, values, largest->get_type()->get_scalar_ty(), id, align_);
}
else
layouts_[id] = new layout_scanline_t(num_warps_, axes, shapes, values, largest->get_type()->get_scalar_ty(), id, align_);
}
void layout::run(ir::module &mod) {
// make graph
graph_.clear();
ir::for_each_instruction(mod, [this](ir::instruction* i) {
make_graph(i);
});
// connected components
graph_.connected_components(&values_, &groups_);
// create layouts
for(const auto& x: values_)
create(x.first, x.second);
}
}
}
}