redesign for faster cpu/gpu synch (#1869)

* redesign for faster cpu/gpu synch

* load + more async CPU

* use command encoder API and move more ops to use it

* make fence back-end generic + CPU only fence

* faster build

* fix async eval

* fixes + handle temporaries

* fix / improve cpu conv

* remove unused status, fix siblings

* fix extensions

* fix

* fix no cpu build

* format

* comments

* fix perf regression, remove unecessary abort

* fix events, task limit cpu

* fix waiting

* fix donation / temporaries in normalization
This commit is contained in:
Awni Hannun
2025-03-06 19:23:38 -08:00
committed by GitHub
parent 5245f12a46
commit c4230747a1
103 changed files with 5013 additions and 3873 deletions

View File

@@ -2,13 +2,18 @@
#include "mlx/allocator.h"
#include "mlx/backend/cpu/copy.h"
#include "mlx/backend/cpu/encoder.h"
#include "mlx/backend/cpu/lapack.h"
#include "mlx/primitives.h"
namespace mlx::core {
template <typename T>
void svd_impl(const array& a, T* u_data, T* s_data, T* vt_data) {
void svd_impl(
const array& a,
std::vector<array>& outputs,
bool compute_uv,
Stream stream) {
// Lapack uses the column-major convention. To avoid having to transpose
// the input and then transpose the outputs, we swap the indices/sizes of the
// matrices and take advantage of the following identity (see
@@ -22,118 +27,24 @@ void svd_impl(const array& a, T* u_data, T* s_data, T* vt_data) {
const int N = a.shape(-1);
const int K = std::min(M, N);
// A of shape M x N. The leading dimension is N since lapack receives Aᵀ.
const int lda = N;
// U of shape M x M. (N x N in lapack).
const int ldu = N;
// Vᵀ of shape N x N. (M x M in lapack).
const int ldvt = M;
size_t num_matrices = a.size() / (M * N);
// lapack clobbers the input, so we have to make a copy.
array in(a.shape(), a.dtype(), nullptr, {});
copy(a, in, a.flags().row_contiguous ? CopyType::Vector : CopyType::General);
copy(
a,
in,
a.flags().row_contiguous ? CopyType::Vector : CopyType::General,
stream);
auto job_u = (u_data && vt_data) ? "V" : "N";
auto job_vt = (u_data && vt_data) ? "V" : "N";
static constexpr auto range = "A";
// Allocate outputs.
auto& encoder = cpu::get_command_encoder(stream);
encoder.set_input_array(a);
auto in_ptr = in.data<T>();
T* u_ptr;
T* s_ptr;
T* vt_ptr;
// Will contain the number of singular values after the call has returned.
int ns = 0;
T workspace_dimension = 0;
// Will contain the indices of eigenvectors that failed to converge (not used
// here but required by lapack).
auto iwork = array::Data{allocator::malloc_or_wait(sizeof(int) * 12 * K)};
static const int lwork_query = -1;
static const int ignored_int = 0;
static const T ignored_float = 0;
static T ignored_output = 0;
int info;
// Compute workspace size.
gesvdx<T>(
/* jobu = */ job_u,
/* jobvt = */ job_vt,
/* range = */ range,
// M and N are swapped since lapack expects column-major.
/* m = */ &N,
/* n = */ &M,
/* a = */ nullptr,
/* lda = */ &lda,
/* vl = */ &ignored_float,
/* vu = */ &ignored_float,
/* il = */ &ignored_int,
/* iu = */ &ignored_int,
/* ns = */ &ns,
/* s = */ nullptr,
/* u = */ nullptr,
/* ldu = */ &ldu,
/* vt = */ nullptr,
/* ldvt = */ &ldvt,
/* work = */ &workspace_dimension,
/* lwork = */ &lwork_query,
/* iwork = */ static_cast<int*>(iwork.buffer.raw_ptr()),
/* info = */ &info);
if (info != 0) {
std::stringstream ss;
ss << "[SVD::eval_cpu] workspace calculation failed with code " << info;
throw std::runtime_error(ss.str());
}
const int lwork = workspace_dimension;
auto scratch = array::Data{allocator::malloc_or_wait(sizeof(T) * lwork)};
// Loop over matrices.
for (int i = 0; i < num_matrices; i++) {
gesvdx<T>(
/* jobu = */ job_u,
/* jobvt = */ job_vt,
/* range = */ range,
// M and N are swapped since lapack expects column-major.
/* m = */ &N,
/* n = */ &M,
/* a = */ in.data<T>() + M * N * i,
/* lda = */ &lda,
/* vl = */ &ignored_float,
/* vu = */ &ignored_float,
/* il = */ &ignored_int,
/* iu = */ &ignored_int,
/* ns = */ &ns,
/* s = */ s_data + K * i,
// According to the identity above, lapack will write Vᵀᵀ as U.
/* u = */ vt_data ? vt_data + N * N * i : &ignored_output,
/* ldu = */ &ldu,
// According to the identity above, lapack will write Uᵀ as Vᵀ.
/* vt = */ u_data ? u_data + M * M * i : &ignored_output,
/* ldvt = */ &ldvt,
/* work = */ static_cast<T*>(scratch.buffer.raw_ptr()),
/* lwork = */ &lwork,
/* iwork = */ static_cast<int*>(iwork.buffer.raw_ptr()),
/* info = */ &info);
if (info != 0) {
std::stringstream ss;
ss << "[SVD::eval_cpu] failed with code " << info;
throw std::runtime_error(ss.str());
}
if (ns != K) {
std::stringstream ss;
ss << "[SVD::eval_cpu] expected " << K << " singular values, but " << ns
<< " were computed.";
throw std::runtime_error(ss.str());
}
}
}
template <typename T>
void compute_svd(const array& a, bool compute_uv, std::vector<array>& outputs) {
if (compute_uv) {
array& u = outputs[0];
array& s = outputs[1];
@@ -143,25 +54,147 @@ void compute_svd(const array& a, bool compute_uv, std::vector<array>& outputs) {
s.set_data(allocator::malloc_or_wait(s.nbytes()));
vt.set_data(allocator::malloc_or_wait(vt.nbytes()));
svd_impl<T>(a, u.data<T>(), s.data<T>(), vt.data<T>());
encoder.set_output_array(u);
encoder.set_output_array(s);
encoder.set_output_array(vt);
s_ptr = s.data<T>();
u_ptr = u.data<T>();
vt_ptr = vt.data<T>();
} else {
array& s = outputs[0];
s.set_data(allocator::malloc_or_wait(s.nbytes()));
svd_impl<T>(a, nullptr, s.data<T>(), nullptr);
encoder.set_output_array(s);
s_ptr = s.data<T>();
u_ptr = nullptr;
vt_ptr = nullptr;
}
encoder.dispatch([in_ptr, u_ptr, s_ptr, vt_ptr, M, N, K, num_matrices]() {
// A of shape M x N. The leading dimension is N since lapack receives Aᵀ.
const int lda = N;
// U of shape M x M. (N x N in lapack).
const int ldu = N;
// Vᵀ of shape N x N. (M x M in lapack).
const int ldvt = M;
auto job_u = (u_ptr) ? "V" : "N";
auto job_vt = (u_ptr) ? "V" : "N";
static constexpr auto range = "A";
// Will contain the number of singular values after the call has returned.
int ns = 0;
T workspace_dimension = 0;
// Will contain the indices of eigenvectors that failed to converge (not
// used here but required by lapack).
auto iwork = array::Data{allocator::malloc_or_wait(sizeof(int) * 12 * K)};
static const int lwork_query = -1;
static const int ignored_int = 0;
static const T ignored_float = 0;
int info;
// Compute workspace size.
gesvdx<T>(
/* jobu = */ job_u,
/* jobvt = */ job_vt,
/* range = */ range,
// M and N are swapped since lapack expects column-major.
/* m = */ &N,
/* n = */ &M,
/* a = */ nullptr,
/* lda = */ &lda,
/* vl = */ &ignored_float,
/* vu = */ &ignored_float,
/* il = */ &ignored_int,
/* iu = */ &ignored_int,
/* ns = */ &ns,
/* s = */ nullptr,
/* u = */ nullptr,
/* ldu = */ &ldu,
/* vt = */ nullptr,
/* ldvt = */ &ldvt,
/* work = */ &workspace_dimension,
/* lwork = */ &lwork_query,
/* iwork = */ static_cast<int*>(iwork.buffer.raw_ptr()),
/* info = */ &info);
if (info != 0) {
std::stringstream ss;
ss << "[SVD::eval_cpu] workspace calculation failed with code " << info;
throw std::runtime_error(ss.str());
}
const int lwork = workspace_dimension;
auto scratch = array::Data{allocator::malloc_or_wait(sizeof(T) * lwork)};
// Loop over matrices.
for (int i = 0; i < num_matrices; i++) {
gesvdx<T>(
/* jobu = */ job_u,
/* jobvt = */ job_vt,
/* range = */ range,
// M and N are swapped since lapack expects column-major.
/* m = */ &N,
/* n = */ &M,
/* a = */ in_ptr + M * N * i,
/* lda = */ &lda,
/* vl = */ &ignored_float,
/* vu = */ &ignored_float,
/* il = */ &ignored_int,
/* iu = */ &ignored_int,
/* ns = */ &ns,
/* s = */ s_ptr + K * i,
// According to the identity above, lapack will write Vᵀᵀ as U.
/* u = */ vt_ptr ? vt_ptr + N * N * i : nullptr,
/* ldu = */ &ldu,
// According to the identity above, lapack will write Uᵀ as Vᵀ.
/* vt = */ u_ptr ? u_ptr + M * M * i : nullptr,
/* ldvt = */ &ldvt,
/* work = */ static_cast<T*>(scratch.buffer.raw_ptr()),
/* lwork = */ &lwork,
/* iwork = */ static_cast<int*>(iwork.buffer.raw_ptr()),
/* info = */ &info);
if (info != 0) {
std::stringstream ss;
ss << "svd_impl: sgesvdx_ failed with code " << info;
throw std::runtime_error(ss.str());
}
if (ns != K) {
std::stringstream ss;
ss << "svd_impl: expected " << K << " singular values, but " << ns
<< " were computed.";
throw std::runtime_error(ss.str());
}
}
});
encoder.add_temporary(in);
}
template <typename T>
void compute_svd(
const array& a,
bool compute_uv,
std::vector<array>& outputs,
Stream stream) {}
void SVD::eval_cpu(
const std::vector<array>& inputs,
std::vector<array>& outputs) {
switch (inputs[0].dtype()) {
case float32:
compute_svd<float>(inputs[0], compute_uv_, outputs);
svd_impl<float>(inputs[0], outputs, compute_uv_, stream());
break;
case float64:
compute_svd<double>(inputs[0], compute_uv_, outputs);
svd_impl<double>(inputs[0], outputs, compute_uv_, stream());
break;
default:
throw std::runtime_error(