Add python bindings to read_tensor_data by olpipi · Pull Request #32984 · openvinotoolkit/openvino

olpipi · 2025-11-21T09:36:04Z

Details:

Add python bindings to read_tensor_data
...

Tickets:

ticket-id

src/bindings/python/src/pyopenvino/pyopenvino.cpp

src/bindings/python/tests/test_runtime/test_read_tensor_data.py

src/bindings/python/src/pyopenvino/core/common.cpp

src/bindings/python/src/openvino/_pyopenvino/__init__.pyi

src/inference/src/dev/make_tensor.cpp

src/bindings/python/src/pyopenvino/core/common.cpp

src/bindings/python/src/pyopenvino/CMakeLists.txt

almilosz · 2026-01-19T10:47:53Z

src/bindings/python/src/pyopenvino/pyopenvino.cpp

    regclass_Tensor(m);
+
+    m.def(
+        "read_tensor_data",


C++ API read_tensor_data is located in src/core/include/openvino/runtime/tensor.hpp
To not bloat pyopenvino.cpp, maybe it's better to move it into regclass Tensor?

openvino/src/bindings/python/src/pyopenvino/core/tensor.cpp

Line 18 in 3f8df69

void regclass_Tensor(py::module m) {

@p-wysocki

src/bindings/python/src/pyopenvino/core/common.cpp

Copilot

Pull request overview

This pull request adds Python bindings for the read_tensor_data C++ function, enabling Python users to load tensor data directly from binary files with memory-mapping support.

Changes:

Added is_tensor_read_only() helper function in C++ to detect read-only tensors
Exposed read_tensor_data function through Python bindings with proper parameter defaults
Modified array_from_tensor to mark numpy arrays as read-only when the underlying tensor is read-only
Added comprehensive test coverage for the new Python API

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/inference/src/dev/make_tensor.cpp	Implements `is_tensor_read_only()` to identify read-only tensor views
src/inference/dev_api/openvino/runtime/make_tensor.hpp	Declares `is_tensor_read_only()` in the dev API with documentation
src/bindings/python/src/pyopenvino/pyopenvino.cpp	Adds Python binding for `read_tensor_data` with proper docstring
src/bindings/python/src/pyopenvino/core/common.cpp	Updates `array_from_tensor` to set numpy array writeable flag based on tensor read-only status
src/bindings/python/src/pyopenvino/CMakeLists.txt	Adds `openvino::runtime::dev` dependency to access dev API functions
src/bindings/python/src/openvino/init.py	Exports `read_tensor_data` in the main Python package
tools/ovc/openvino/init.py	Exports `read_tensor_data` in the OVC tool package
tools/benchmark_tool/openvino/init.py	Exports `read_tensor_data` in the benchmark tool package
src/bindings/python/tests/test_runtime/test_read_tensor_data.py	Comprehensive test suite covering various use cases and edge cases

Copilot · 2026-02-24T06:24:43Z

src/inference/src/dev/make_tensor.cpp

+bool is_tensor_read_only(const ov::Tensor& tensor) {
+    auto impl = get_tensor_impl(tensor);
+    if (std::dynamic_pointer_cast<ViewTensor>(impl._ptr)) {
+        return true;
+    }
+    return false;
+}


[BLOCKER] The is_tensor_read_only function incorrectly identifies all ViewTensor subclasses as read-only, including writable ones. The current implementation checks for ViewTensor base class, but AllocatedTensor (which owns and manages writable memory) and StridedViewTensor (writable view with strides) also inherit from ViewTensor. This will cause normal allocated tensors and writable view tensors to be incorrectly marked as read-only in Python.

The function should specifically check for ReadOnlyViewTensor and ReadOnlyStridedViewTensor, not the base ViewTensor class. The correct implementation should be:

bool is_tensor_read_only(const ov::Tensor& tensor) { auto impl = get_tensor_impl(tensor); if (std::dynamic_pointer_cast<ReadOnlyViewTensor>(impl._ptr) || std::dynamic_pointer_cast<ReadOnlyStridedViewTensor>(impl._ptr)) { return true; } return false; }

This is critical because it affects the Python bindings' behavior - regular allocated tensors would become read-only incorrectly, breaking existing functionality.

Copilot

Pull request overview

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/bindings/python/tests/test_runtime/test_read_tensor_data.py:104

This call formatting is inconsistent with the rest of the file (closing parenthesis on the same line as the last argument). Consider formatting it like the other multi-line calls (or running the project formatter) to keep the test file style consistent.

        ov.read_tensor_data(
            path,
            element_type=ov.Type.f32,
            shape=ov.PartialShape(list(shape)),
            offset_in_bytes=1,
            mmap=mmap)

Copilot · 2026-02-25T08:25:53Z

src/bindings/python/src/pyopenvino/core/common.cpp

+    auto data_ptr = std::as_const(t).data();
+    auto is_read_only = ov::is_tensor_read_only(t);
+
    // Return the array as a view:
    if (is_shared) {
+        py::array result;
        if (ov_type.bitwidth() < Common::values::min_bitwidth) {
-            return py::array(dtype, t.get_byte_size(), t.data(), py::cast(t));
+            result = py::array(dtype, t.get_byte_size(), data_ptr, py::cast(t));
+        } else {
+            result = py::array(dtype, t.get_shape(), t.get_strides(), data_ptr, py::cast(t));
+        }
+        if (is_read_only) {
+            // Mark array as read-only
+            result.attr("flags").attr("writeable") = false;
        }
-        return py::array(dtype, t.get_shape(), t.get_strides(), t.data(), py::cast(t));
+        return result;
    }


This changes the Python-visible mutability semantics for any tensor detected as ViewTensor by is_tensor_read_only(). If writable view tensors exist, they will now surface as non-writeable NumPy arrays, which is a breaking behavior change for Python users. Once is_tensor_read_only() is corrected to match the intended 'const-host view' definition, this risk should be mitigated; alternatively, scope the read-only marking to tensors created by read_tensor_data (if there is a reliable way to tag/detect that provenance).

Copilot · 2026-02-25T08:25:54Z

src/inference/dev_api/openvino/runtime/make_tensor.hpp

+ * @details A tensor is considered read-only if it was created as a view tensor from a const pointer
+ * using the make_tensor() function that accepts const void* host_ptr.
+ *
+ * @param tensor OpenVINO Tensor to check
+ *
+ * @return true if the tensor is read-only, false otherwise


The documented definition ('view tensor from a const pointer') doesn’t match the current implementation (which checks only whether the impl is ViewTensor). Either tighten the implementation to reflect this definition, or update the documentation to describe the actual condition being tested so callers don’t rely on incorrect semantics.

Suggested change

* @details A tensor is considered read-only if it was created as a view tensor from a const pointer

* using the make_tensor() function that accepts const void* host_ptr.

*

* @param tensor OpenVINO Tensor to check

*

* @return true if the tensor is read-only, false otherwise

* @details A tensor is considered read-only when its underlying implementation is a view

* tensor that represents a non-mutable view on existing memory. This typically includes

* tensors created by the make_tensor() overload that accepts const void* host_ptr, as

* well as other APIs that may return ViewTensor-based read-only views.

*

* @note The exact condition checked by this function is whether the internal ITensor

* implementation is of type ViewTensor; callers must not rely on more specific semantics

* such as how the tensor view was originally constructed.

*

* @param tensor OpenVINO Tensor to check

*

* @return true if the tensor is read-only according to the above condition, false otherwise

github-actions bot added category: Python API OpenVINO Python bindings category: tools OpenVINO C++ / Python tools category: OVC OVC tool labels Nov 21, 2025

olpipi changed the title ~~Add bindings to read_tensor_data~~ [TEST PR] Add bindings to read_tensor_data Nov 21, 2025

mlukasze requested review from almilosz and p-wysocki November 21, 2025 10:30

praasz reviewed Nov 21, 2025

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olpipi force-pushed the read_tensor_data_py branch from 8e56854 to 56a5139 Compare January 7, 2026 15:34

olpipi changed the title ~~[TEST PR] Add bindings to read_tensor_data~~ Add python bindings to read_tensor_data Jan 7, 2026

olpipi marked this pull request as ready for review January 7, 2026 16:18

olpipi requested review from a team as code owners January 7, 2026 16:18

olpipi requested a review from praasz January 7, 2026 16:18

olpipi force-pushed the read_tensor_data_py branch from 835410a to f5c5a3b Compare January 7, 2026 16:22

praasz assigned praasz and almilosz Jan 8, 2026

praasz reviewed Jan 8, 2026

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almilosz reviewed Jan 8, 2026

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src/bindings/python/src/openvino/_pyopenvino/__init__.pyi Outdated Show resolved Hide resolved

olpipi requested a review from a team as a code owner January 8, 2026 15:53

github-actions bot added category: inference OpenVINO Runtime library - Inference category: build OpenVINO cmake script / infra labels Jan 8, 2026

praasz reviewed Jan 9, 2026

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src/inference/src/dev/make_tensor.cpp Show resolved Hide resolved

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praasz added this to the 2026.0 milestone Jan 9, 2026

almilosz reviewed Jan 19, 2026

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olpipi added 2 commits January 19, 2026 17:33

Add bindings to read_tensor_data

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dce9734

olpipi force-pushed the read_tensor_data_py branch from e0ff46e to dce9734 Compare January 19, 2026 16:33

praasz modified the milestones: 2026.0, 2026.1 Jan 20, 2026

Merge branch 'master' into read_tensor_data_py

3d9f4f5

mlukasze requested a review from Copilot February 24, 2026 06:19

Copilot started reviewing on behalf of mlukasze February 24, 2026 06:20 View session

Copilot AI reviewed Feb 24, 2026

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praasz requested a review from Copilot February 25, 2026 08:19

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Copilot started reviewing on behalf of praasz February 25, 2026 09:18 View session

Merge branch 'master' into read_tensor_data_py

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Add python bindings to read_tensor_data#32984

Add python bindings to read_tensor_data#32984
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olpipi commented Nov 21, 2025 •

edited

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- * @details A tensor is considered read-only if it was created as a view tensor from a const pointer
- * using the make_tensor() function that accepts const void* host_ptr.
- *
- * @param tensor OpenVINO Tensor to check
- *
- * @return true if the tensor is read-only, false otherwise
+ * @details A tensor is considered read-only when its underlying implementation is a view
+ * tensor that represents a non-mutable view on existing memory. This typically includes
+ * tensors created by the make_tensor() overload that accepts const void* host_ptr, as
+ * well as other APIs that may return ViewTensor-based read-only views.
+ *
+ * @note The exact condition checked by this function is whether the internal ITensor
+ * implementation is of type ViewTensor; callers must not rely on more specific semantics
+ * such as how the tensor view was originally constructed.
+ *
+ * @param tensor OpenVINO Tensor to check
+ *
+ * @return true if the tensor is read-only according to the above condition, false otherwise

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olpipi commented Nov 21, 2025 •

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