Investigating the root cause of the issue

Oct 13, 2025 by wbrum.org 84 views

Introduction

The SFPU (Single Floating-Point Unit) is a crucial component in modern computing architectures, enabling efficient execution of floating-point operations. However, issues with SFPU example code can hinder development and optimization of applications. In this article, we will delve into the 'eltwise_sfpu' programming example, which fails on both WH (Wide Hardware) and BH (Base Hardware) platforms. We will explore the suspected changes made to the function 'llk_unpack_A_hw_configure' and provide a step-by-step guide to reproduce the behavior.

Describe the Bug

The 'eltwise_sfpu' programming example fails on both WH and BH platforms, indicating a potential issue with the SFPU implementation. The error message suggests that the function 'llk_unpack_A_hw_configure' is not configured correctly, leading to a mismatch in function calls.

To Reproduce

To reproduce the behavior, follow these steps:

Step 1: Access tt_metal

Access the tt_metal directory, which contains the necessary files and scripts for building and running the programming examples.

Step 2: Build Programming Examples

Run the build_metal.sh script with the --build-programming-examples flag to build the programming examples.

./build_metal.sh --build-programming-examples

Step 3: Build Eltwise SFPU Example

Navigate to the build/programming_examples directory and run the eltwise_sfpu build script.

./build/programming_examples/eltwise_sfpu

Expected Behavior

The 'eltwise_sfpu' programming example should pass without any errors. However, the current implementation fails, indicating a bug in the SFPU code.

Screenshots

The error message is displayed in the llk_unpack_A_api.h file, highlighting the issue with the function call.

llk_unpack_A_api.h:23:92: error: no matching function for call to '_llk_unpack_A_hw_configure_<false, ckernel::StochRndType::None, true>(const int32_t&, const int32_t&, const uint32_t&, const int&, const uint32_t&)'

Environment Information

The following environment information is relevant to this issue:

Git Commit: ae892c4b3af98936de8ae4ccbdd193727aed4b0a

Suspected Changes

The suspected changes made to the function 'llk_unpack_A_hw_configure' are likely the cause of the issue. The function is not configured correctly, leading to a mismatch in function calls.

Debugging and Resolution

To resolve this issue, we need to investigate the changes made to the function 'llk_unpack_A_hw_configure'. We can start by reviewing the commit history and identifying the specific changes that introduced the bug.

Step 1: Review Commit History

Review the commit history to identify the specific changes made to the function 'llk_unpack_A_hw_configure'.

Step 2: Investigate Changes

Investigate the changes made to the function 'llk_unpack_A_hw_configure' and identify the root cause of the issue.

Step 3: Resolve Issue

Resolve the issue by correcting the function 'llk_unpack_A_hw_configure' and re-building the programming examples.

Conclusion

The 'eltwise_sfpu' programming example fails on both WH and BH platforms due to a suspected issue with the function 'llk_unpack_A_hw_configure'. By following the steps outlined in this article, we can reproduce the behavior, identify the root cause of the issue, and resolve the problem. The suspected changes made to the function 'llk_unpack_A_hw_configure' are likely the cause of the issue, and correcting these changes will resolve the problem.

Future Work

Future work includes:

Investigating the root cause of the issue: Further investigation is required to identify the root cause of the issue and ensure that the corrected function 'llk_unpack_A_hw_configure' is stable and efficient.
Testing and validation: Thorough testing and validation are necessary to ensure that the corrected function 'llk_unpack_A_hw_configure' works correctly on both WH and BH platforms.
Documentation and maintenance: Documentation and maintenance of the corrected function 'llk_unpack_A_hw_configure' are essential to ensure that the changes are properly documented and maintained for future reference.
SFPU Example Code Failing: Eltwise SFPU Bug - Q&A =====================================================

Introduction

In our previous article, we explored the 'eltwise_sfpu' programming example, which fails on both WH (Wide Hardware) and BH (Base Hardware) platforms. We identified the suspected changes made to the function 'llk_unpack_A_hw_configure' as the root cause of the issue. In this article, we will provide a Q&A section to address common questions and concerns related to this issue.

Q&A

Q: What is the SFPU and why is it important?

A: The SFPU (Single Floating-Point Unit) is a crucial component in modern computing architectures, enabling efficient execution of floating-point operations. It is essential for applications that require high-performance computing, such as scientific simulations, machine learning, and data analytics.

Q: What is the 'eltwise_sfpu' programming example and why is it failing?

A: The 'eltwise_sfpu' programming example is a test case that exercises the SFPU functionality. It fails on both WH and BH platforms due to a suspected issue with the function 'llk_unpack_A_hw_configure'.

Q: What are the suspected changes made to the function 'llk_unpack_A_hw_configure'?

A: The suspected changes made to the function 'llk_unpack_A_hw_configure' are likely the cause of the issue. The function is not configured correctly, leading to a mismatch in function calls.

Q: How can I reproduce the behavior?

A: To reproduce the behavior, follow these steps:

Access the tt_metal directory.
Run the build_metal.sh script with the --build-programming-examples flag to build the programming examples.
Navigate to the build/programming_examples directory and run the eltwise_sfpu build script.

Q: What is the expected behavior?

A: The 'eltwise_sfpu' programming example should pass without any errors. However, the current implementation fails, indicating a bug in the SFPU code.

Q: What are the possible causes of the issue?

A: The possible causes of the issue include:

Incorrect configuration of the function 'llk_unpack_A_hw_configure'.
Mismatch in function calls.
Incompatible hardware or software configurations.

Q: How can I resolve the issue?

A: To resolve the issue, follow these steps:

Review the commit history to identify the specific changes made to the function 'llk_unpack_A_hw_configure'.
Investigate the changes made to the function 'llk_unpack_A_hw_configure' and identify the root cause of the issue.
Correct the function 'llk_unpack_A_hw_configure' and re-build the programming examples.

Q: What are the next steps?

A: The next steps include:

Investigating the root cause of the issue and ensuring that the corrected function 'llk_unpack_A_hw_configure' is stable and efficient.
Testing and validation of the corrected function 'llk_unpack_A_hw_configure' on both WH and BH platforms.
Documentation and maintenance of the corrected function 'llk_unpack_A_hw_configure'.

Conclusion

Future Work

Future work includes:

Investigating the root cause of the issue and ensuring that the corrected function 'llk_unpack_A_hw_configure' is stable and efficient.
Testing and validation of the corrected function 'llk_unpack_A_hw_configure' on both WH and BH platforms.
Documentation and maintenance of the corrected function 'llk_unpack_A_hw_configure'.