Fix CUDA kernel index data type in vision/fair/pytorch3d/pytorch3d/csrc/compositing/alpha_composite.cu +10

Summary:
CUDA kernel variables matching the type `(thread|block|grid).(Idx|Dim).(x|y|z)` [have the data type `uint`](https://docs.nvidia.com/cuda/cuda-c-programming-guide/#built-in-variables).

Many programmers mistakenly use implicit casts to turn these data types into `int`. In fact, the [CUDA Programming Guide](https://docs.nvidia.com/cuda/cuda-c-programming-guide/) it self is inconsistent and incorrect in its use of data types in programming examples.

The result of these implicit casts is that our kernels may give unexpected results when exposed to large datasets, i.e., those exceeding >~2B items.

While we now have linters in place to prevent simple mistakes (D71236150), our codebase has many problematic instances. This diff fixes some of them.

Reviewed By: dtolnay

Differential Revision: D71355356

fbshipit-source-id: cea44891416d9efd2f466d6c45df4e36008fa036
This commit is contained in:
Richard Barnes
2025-03-19 13:21:43 -07:00
committed by Facebook GitHub Bot
parent 06a76ef8dd
commit 3987612062
10 changed files with 54 additions and 54 deletions

View File

@@ -260,8 +260,8 @@ __global__ void RasterizeMeshesNaiveCudaKernel(
float* pix_dists,
float* bary) {
// Simple version: One thread per output pixel
int num_threads = gridDim.x * blockDim.x;
int tid = blockDim.x * blockIdx.x + threadIdx.x;
auto num_threads = gridDim.x * blockDim.x;
auto tid = blockDim.x * blockIdx.x + threadIdx.x;
for (int i = tid; i < N * H * W; i += num_threads) {
// Convert linear index to 3D index
@@ -446,8 +446,8 @@ __global__ void RasterizeMeshesBackwardCudaKernel(
// Parallelize over each pixel in images of
// size H * W, for each image in the batch of size N.
const int num_threads = gridDim.x * blockDim.x;
const int tid = blockIdx.x * blockDim.x + threadIdx.x;
const auto num_threads = gridDim.x * blockDim.x;
const auto tid = blockIdx.x * blockDim.x + threadIdx.x;
for (int t_i = tid; t_i < N * H * W; t_i += num_threads) {
// Convert linear index to 3D index
@@ -650,8 +650,8 @@ __global__ void RasterizeMeshesFineCudaKernel(
) {
// This can be more than H * W if H or W are not divisible by bin_size.
int num_pixels = N * BH * BW * bin_size * bin_size;
int num_threads = gridDim.x * blockDim.x;
int tid = blockIdx.x * blockDim.x + threadIdx.x;
auto num_threads = gridDim.x * blockDim.x;
auto tid = blockIdx.x * blockDim.x + threadIdx.x;
for (int pid = tid; pid < num_pixels; pid += num_threads) {
// Convert linear index into bin and pixel indices. We make the within