Merge pull request #1890 from IntelPython/fix-gh-1887

Check pointer alignment when copying from strided array to C-contiguous array

Author: ndgrigorian

CHANGELOG.md

@@ -18,8 +18,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 * Fix for `tensor.result_type` when all inputs are Python built-in scalars [gh-1877](https://github.com/IntelPython/dpctl/pull/1877)
-
 * Improved error in constructors `tensor.full` and `tensor.full_like` when provided a non-numeric fill value [gh-1878](https://github.com/IntelPython/dpctl/pull/1878)
+* Added a check for pointer alignment when copying to C-contiguous memory [gh-1890](https://github.com/IntelPython/dpctl/pull/1890)
 
 ### Maintenance
 

dpctl/tensor/libtensor/include/kernels/copy_as_contiguous.hpp

@@ -44,8 +44,8 @@ namespace copy_as_contig
 
 template <typename T,
  typename IndexerT,
- int vec_sz = 4,
- int n_vecs = 2,
+ std::uint32_t vec_sz = 4u,
+ std::uint32_t n_vecs = 2u,
  bool enable_sg_loadstore = true>
 class CopyAsCContigFunctor
 {
@@ -66,53 +66,63 @@ class CopyAsCContigFunctor
 
  void operator()(sycl::nd_item<1> ndit) const
  {
+ static_assert(vec_sz > 0);
+ static_assert(n_vecs > 0);
+ static_assert(vec_sz * n_vecs < (std::uint32_t(1) << 8));
+
+ constexpr std::uint8_t elems_per_wi =
+ static_cast<std::uint8_t>(vec_sz * n_vecs);
+
  using dpctl::tensor::type_utils::is_complex;
  if constexpr (!enable_sg_loadstore || is_complex<T>::value) {
- const std::uint32_t sgSize =
+ const std::uint16_t sgSize =
  ndit.get_sub_group().get_local_range()[0];
  const std::size_t gid = ndit.get_global_linear_id();
 
- const std::size_t base =
- (gid / sgSize) * sgSize * n_vecs * vec_sz + (gid % sgSize);
- for (size_t offset = base;
- offset < std::min(nelems, base + sgSize * (n_vecs * vec_sz));
- offset += sgSize)
- {
+ // base = (gid / sgSize) * sgSize * elems_per_wi + (gid % sgSize)
+ // gid % sgSize == gid - (gid / sgSize) * sgSize
+ const std::size_t elems_per_sg = sgSize * (elems_per_wi - 1);
+ const std::size_t base = (gid / sgSize) * elems_per_sg + gid;
+ const std::size_t offset_max =
+ std::min(nelems, base + sgSize * elems_per_wi);
+
+ for (size_t offset = base; offset < offset_max; offset += sgSize) {
  auto src_offset = src_indexer(offset);
  dst_p[offset] = src_p[src_offset];
  }
  }
  else {
  auto sg = ndit.get_sub_group();
- const std::uint32_t sgSize = sg.get_local_range()[0];
- const size_t base = n_vecs * vec_sz *
-   (ndit.get_group(0) * ndit.get_local_range(0) +
-  sg.get_group_id()[0] * sgSize);
+ const std::uint16_t sgSize = sg.get_max_local_range()[0];
+ const size_t base =
+ elems_per_wi * (ndit.get_group(0) * ndit.get_local_range(0) +
+ sg.get_group_id()[0] * sgSize);
 
- if (base + n_vecs * vec_sz * sgSize < nelems) {
+ if (base + elems_per_wi * sgSize < nelems) {
  sycl::vec<T, vec_sz> dst_vec;
 
 #pragma unroll
- for (std::uint32_t it = 0; it < n_vecs * vec_sz; it += vec_sz) {
+ for (std::uint8_t it = 0; it < elems_per_wi; it += vec_sz) {
+ const size_t block_start_id = base + it * sgSize;
  auto dst_multi_ptr = sycl::address_space_cast<
  sycl::access::address_space::global_space,
- sycl::access::decorated::yes>(
- &dst_p[base + it * sgSize]);
+ sycl::access::decorated::yes>(&dst_p[block_start_id]);
 
+ const size_t elem_id0 = block_start_id + sg.get_local_id();
 #pragma unroll
- for (std::uint32_t k = 0; k < vec_sz; k++) {
- ssize_t src_offset = src_indexer(
-  base + (it + k) * sgSize + sg.get_local_id());
+ for (std::uint8_t k = 0; k < vec_sz; k++) {
+ const size_t elem_id = elem_id0 + k * sgSize;
+ const ssize_t src_offset = src_indexer(elem_id);
  dst_vec[k] = src_p[src_offset];
  }
  sg.store<vec_sz>(dst_multi_ptr, dst_vec);
  }
  }
  else {
- for (size_t k = base + sg.get_local_id()[0]; k < nelems;
-  k += sgSize)
- {
- ssize_t src_offset = src_indexer(k);
+ const size_t lane_id = sg.get_local_id()[0];
+ const size_t k0 = base + lane_id;
+ for (size_t k = k0; k < nelems; k += sgSize) {
+ const ssize_t src_offset = src_indexer(k);
  dst_p[k] = src_p[src_offset];
  }
  }
@@ -121,36 +131,23 @@ class CopyAsCContigFunctor
 };
 
 template <typename T,
- typename IndexT,
- int vec_sz,
- int n_vecs,
- bool enable_sgload>
-class as_contig_krn;
-
-template <typename T>
-sycl::event
-as_c_contiguous_array_generic_impl(sycl::queue &exec_q,
- size_t nelems,
- int nd,
- const ssize_t *shape_and_strides,
- const char *src_p,
- char *dst_p,
- const std::vector<sycl::event> &depends)
+ typename IndexerT,
+ std::uint32_t vec_sz,
+ std::uint32_t n_vecs,
+ bool enable_sg_load,
+ typename KernelName>
+sycl::event submit_c_contiguous_copy(sycl::queue &exec_q,
+ size_t nelems,
+ const T *src,
+ T *dst,
+ const IndexerT &src_indexer,
+ const std::vector<sycl::event> &depends)
 {
- dpctl::tensor::type_utils::validate_type_for_device<T>(exec_q);
-
- const T *src_tp = reinterpret_cast<const T *>(src_p);
- T *dst_tp = reinterpret_cast<T *>(dst_p);
-
- using IndexerT = dpctl::tensor::offset_utils::StridedIndexer;
- const IndexerT src_indexer(nd, ssize_t(0), shape_and_strides);
+ static_assert(vec_sz > 0);
+ static_assert(n_vecs > 0);
+ static_assert(vec_sz * n_vecs < (std::uint32_t(1) << 8));
 
  constexpr std::size_t preferred_lws = 256;
- constexpr std::uint32_t n_vecs = 2;
- constexpr std::uint32_t vec_sz = 4;
- constexpr bool enable_sg_load = true;
- using KernelName =
- as_contig_krn<T, IndexerT, vec_sz, n_vecs, enable_sg_load>;
 
  const auto &kernel_id = sycl::get_kernel_id<KernelName>();
 
@@ -167,9 +164,11 @@ as_c_contiguous_array_generic_impl(sycl::queue &exec_q,
  const std::size_t lws =
  ((preferred_lws + max_sg_size - 1) / max_sg_size) * max_sg_size;
 
- constexpr std::uint32_t nelems_per_wi = n_vecs * vec_sz;
- size_t n_groups =
- (nelems + nelems_per_wi * lws - 1) / (nelems_per_wi * lws);
+ constexpr std::uint8_t nelems_per_wi = n_vecs * vec_sz;
+
+ const size_t nelems_per_group = nelems_per_wi * lws;
+ const size_t n_groups =
+ (nelems + nelems_per_group - 1) / (nelems_per_group);
 
  sycl::event copy_ev = exec_q.submit([&](sycl::handler &cgh) {
  cgh.depends_on(depends);
@@ -181,8 +180,62 @@ as_c_contiguous_array_generic_impl(sycl::queue &exec_q,
  cgh.parallel_for<KernelName>(
  sycl::nd_range<1>(gRange, lRange),
  CopyAsCContigFunctor<T, IndexerT, vec_sz, n_vecs, enable_sg_load>(
- nelems, src_tp, dst_tp, src_indexer));
+ nelems, src, dst, src_indexer));
  });
+ return copy_ev;
+}
+
+template <typename T,
+ typename IndexT,
+ std::uint32_t vec_sz,
+ std::uint32_t n_vecs,
+ bool enable_sgload>
+class as_contig_krn;
+
+template <typename T>
+sycl::event
+as_c_contiguous_array_generic_impl(sycl::queue &exec_q,
+ size_t nelems,
+ int nd,
+ const ssize_t *shape_and_strides,
+ const char *src_p,
+ char *dst_p,
+ const std::vector<sycl::event> &depends)
+{
+ dpctl::tensor::type_utils::validate_type_for_device<T>(exec_q);
+
+ const T *src_tp = reinterpret_cast<const T *>(src_p);
+ T *dst_tp = reinterpret_cast<T *>(dst_p);
+
+ using IndexerT = dpctl::tensor::offset_utils::StridedIndexer;
+ const IndexerT src_indexer(nd, ssize_t(0), shape_and_strides);
+
+ constexpr std::uint32_t vec_sz = 4u;
+ constexpr std::uint32_t n_vecs = 2u;
+
+ using dpctl::tensor::kernels::alignment_utils::
+ disabled_sg_loadstore_wrapper_krn;
+ using dpctl::tensor::kernels::alignment_utils::is_aligned;
+ using dpctl::tensor::kernels::alignment_utils::required_alignment;
+
+ sycl::event copy_ev;
+ if (is_aligned<required_alignment>(dst_p)) {
+ constexpr bool enable_sg_load = true;
+ using KernelName =
+ as_contig_krn<T, IndexerT, vec_sz, n_vecs, enable_sg_load>;
+ copy_ev = submit_c_contiguous_copy<T, IndexerT, vec_sz, n_vecs,
+ enable_sg_load, KernelName>(
+ exec_q, nelems, src_tp, dst_tp, src_indexer, depends);
+ }
+ else {
+ constexpr bool disable_sg_load = false;
+ using InnerKernelName =
+ as_contig_krn<T, IndexerT, vec_sz, n_vecs, disable_sg_load>;
+ using KernelName = disabled_sg_loadstore_wrapper_krn<InnerKernelName>;
+ copy_ev = submit_c_contiguous_copy<T, IndexerT, vec_sz, n_vecs,
+ disable_sg_load, KernelName>(
+ exec_q, nelems, src_tp, dst_tp, src_indexer, depends);
+ }
 
  return copy_ev;
 }

dpctl/tests/test_usm_ndarray_ctor.py

@@ -2632,3 +2632,19 @@ def test_full_functions_raise_type_error():
  x = dpt.ones(1, dtype="i4")
  with pytest.raises(TypeError):
  dpt.full_like(x, "0")
+
+
+@pytest.mark.parametrize("dt", _all_dtypes)
+def test_setitem_copy_as_contig_alignment(dt):
+ q = get_queue_or_skip()
+ skip_if_dtype_not_supported(dt, q)
+
+ dtype_ = dpt.dtype(dt)
+ n0, n1 = 8, 23
+
+ x = dpt.zeros((n0, n1), dtype=dtype_, sycl_queue=q)
+
+ vals = dpt.ones(n1, dtype=dtype_, sycl_queue=q)[dpt.newaxis, :]
+ x[1:, ...] = vals
+ assert dpt.all(x[0] == 0)
+ assert dpt.all(x[1:, :] == vals)