[Performance] Mapfile support for certain external data files is not working

[ivberg]

Describe the issue

We are attempting to get mapfile support working well using external data files. The model loads fine and works, but while debugging we noticed mapfile support is not working well and error'ing out inside ORT code

#19089
https://github.com/onnx/onnx/blob/main/docs/ExternalData.md

Callstack where the mapfile fails due to alignment issues:
00 ps_onnxruntime!onnxruntime::WindowsEnv::MapFileIntoMemory+0xa90 [D:\a_work\1\s\onnxruntime\onnxruntime\core\platform\windows\env.cc @ 449] // Failure here
01 ps_onnxruntime!onnxruntime::utils::GetFileContent+0x12c [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\tensorprotoutils.cc @ 899]
02 ps_onnxruntime!onnxruntime::utils::GetExtDataFromTensorProto+0x484 [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\tensorprotoutils.cc @ 1015] // The buffer size, length is coming from here
03 ps_onnxruntime!onnxruntime::session_state_utils::ExtDataTensorProtoToTensor+0x8c [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\session_state_utils.cc @ 73]
04 ps_onnxruntime!onnxruntime::session_state_utils::DeserializeTensorProto+0x37c [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\session_state_utils.cc @ 126]
05 ps_onnxruntime!onnxruntime::session_state_utils::SaveInitializedTensors+0x1208 [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\session_state_utils.cc @ 310]
06 ps_onnxruntime!onnxruntime::SessionState::FinalizeSessionStateImpl+0x76c [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\session_state.cc @ 1476]
07 ps_onnxruntime!onnxruntime::SessionState::FinalizeSessionState+0x1b4 [D:\a_work\1\s\onnxruntime\onnxruntime\core\framework\session_state.cc @ 1189]
08 ps_onnxruntime!onnxruntime::InferenceSession::Initialize+0x2178 [D:\a_work\1\s\onnxruntime\onnxruntime\core\session\inference_session.cc @ 2015]
09 ps_onnxruntime!`anonymous namespace'::InitializeSession+0x250 [D:\a_work\1\s\onnxruntime\onnxruntime\core\session\onnxruntime_c_api.cc @ 763]
0a ps_onnxruntime!OrtApis::CreateSession+0xa0 [D:\a_work\1\s\onnxruntime\onnxruntime\core\session\onnxruntime_c_api.cc @ 779]

Instead we are hitting an error "mapped offset must be a multiple of the allocation granularity"..." from ORT and swallowing it. I say swallowing it because as per other stack yes we go on the error path reading the whole file into the buffer as backup.

To reproduce

Get a model with external data file. e.g. model.onnx & model.onnx.data. Not all files will reproduce the issue due to alignment with the target OS

const ORTCHAR_T * filemodelpath = ORT_TSTR("model.onnx");
Load with: Ort::Session(env, filemodelpath, session_options);

// The model seems to load fine and works with external data file

Urgency

Fairly urgent

For now trying workaround with AddExternalInitializersFromFilesInMemory

Platform

Windows

OS Version

23H2

ONNX Runtime Installation

Built from Source

ONNX Runtime Version or Commit ID

55f7f9d

ONNX Runtime API

C++

Architecture

ARM64

Execution Provider

Default CPU

Execution Provider Library Version

No response

Model File

No response

Is this a quantized model?

Yes

[pranavsharma]

Can you attach a sample model? and this happens on ARM64 only?

[ivberg]

We are seeing about sharing the model directly. It seems the alignment issue could happen on multiple platforms. I happen to be testing / using ARM64 though.

[justinchuby]

External data produced by the ONNX exporter by PyTorch 2.5 will be aligned.