Files
2026-07-13 12:45:52 +08:00

153 lines
4.4 KiB
C++

// basic tool to experiment with the Metal backend
//
// 1. Get GPU trace of a dummy graph:
//
// rm -rf /tmp/perf-metal.gputrace
// make -j perf-metal && METAL_CAPTURE_ENABLED=1 ./bin/perf-metal
// open /tmp/perf-metal.gputrace
//
// https://github.com/ggerganov/llama.cpp/issues/9507
//
#include "ggml.h"
#include "ggml-alloc.h"
#include "ggml-backend.h"
#include "ggml-metal.h"
#include <cstdio>
#include <vector>
#include <thread>
int main(int argc, char ** argv) {
int n_op = 1024;
int n_iter = 128;
if (argc > 1) {
n_op = std::atoi(argv[1]);
}
if (argc > 2) {
n_iter = std::atoi(argv[2]);
}
printf("%s: n_op = %d, n_iter = %d\n", __func__, n_op, n_iter);
const int ne00 = 8;
const int ne01 = 8;
const int ne11 = 8;
std::vector<float> data0(ne00*ne01, 1.0f);
std::vector<float> data1(ne00*ne01, 1.0f/ne00);
ggml_backend_t backend = ggml_backend_metal_init();
if (!backend) {
fprintf(stderr, "%s: ggml_backend_metal_init() failed\n", __func__);
return 1;
}
const size_t ctx_size = 2 * ggml_tensor_overhead();
struct ggml_init_params params = {
/*.mem_size =*/ ctx_size,
/*.mem_buffer =*/ NULL,
/*.no_alloc =*/ true,
};
struct ggml_context * ctx = ggml_init(params);
struct ggml_tensor * t0 = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, ne00, ne01);
struct ggml_tensor * t1 = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, ne00, ne11);
ggml_backend_buffer_t buffer = ggml_backend_alloc_ctx_tensors(ctx, backend);
ggml_backend_tensor_set(t0, data0.data(), 0, ggml_nbytes(t0));
ggml_backend_tensor_set(t1, data1.data(), 0, ggml_nbytes(t1));
struct ggml_cgraph * gf = NULL;
struct ggml_context * ctx_cgraph = NULL;
// create a dummy compute graph:
//
// x = mul_mat(t0, t1)
// x = x * 1.0f
// x = mul_mat(x, t1)
// x = x * 1.0f
// ... repeat n_op times ...
//
{
struct ggml_init_params params0 = {
/*.mem_size =*/ 4*n_op*ggml_tensor_overhead() + ggml_graph_overhead(),
/*.mem_buffer =*/ NULL,
/*.no_alloc =*/ true,
};
ctx_cgraph = ggml_init(params0);
gf = ggml_new_graph_custom(ctx_cgraph, 4*n_op, false);
struct ggml_tensor * cur = ggml_mul_mat(ctx_cgraph, t0, t1);
cur = ggml_scale(ctx_cgraph, cur, 1.0f);
for (int i = 0; i < n_op - 1; i++) {
cur = ggml_mul_mat(ctx_cgraph, cur, t1);
cur = ggml_scale(ctx_cgraph, cur, 1.0f);
}
cur = ggml_scale(ctx_cgraph, cur, 42.0f);
ggml_build_forward_expand(gf, cur);
}
printf("%s: graph nodes = %d\n", __func__, ggml_graph_n_nodes(gf));
ggml_gallocr_t allocr = ggml_gallocr_new(ggml_backend_get_default_buffer_type(backend));
ggml_gallocr_alloc_graph(allocr, gf);
{
// warm-up
ggml_backend_graph_compute(backend, gf);
const int64_t t_start = ggml_time_us();
for (int iter = 0; iter < n_iter; iter++) {
ggml_backend_graph_compute(backend, gf);
}
const int64_t t_end = ggml_time_us();
// actual trace
ggml_backend_metal_capture_next_compute(backend);
ggml_backend_graph_compute(backend, gf);
//std::this_thread::sleep_for(std::chrono::milliseconds(1000)); // NOTE: these intervals do not appear in the XCode trace!
ggml_backend_metal_capture_next_compute(backend);
ggml_backend_graph_compute(backend, gf);
//std::this_thread::sleep_for(std::chrono::milliseconds(1000)); // NOTE: these intervals do not appear in the XCode trace!
ggml_backend_metal_capture_next_compute(backend);
ggml_backend_graph_compute(backend, gf);
printf("%s: time = %f ms\n", __func__, (t_end - t_start) / 1000.0 / n_iter);
}
{
struct ggml_tensor * res = ggml_graph_node(gf, -1);
std::vector<float> data(res->ne[0] * res->ne[1], 0.0f);
ggml_backend_tensor_get(res, data.data(), 0, ggml_nbytes(res));
for (int i1 = 0; i1 < res->ne[1]; i1++) {
for (int i0 = 0; i0 < res->ne[0]; i0++) {
printf("%f ", data[i1*res->ne[0] + i0]);
}
printf("\n");
}
}
ggml_free(ctx_cgraph);
ggml_gallocr_free(allocr);
ggml_free(ctx);
ggml_backend_buffer_free(buffer);
ggml_backend_free(backend);
return 0;
}