[RPP] Add rocFFT GPU acceleration for audio spectrogram (AICV-283) by LakshmiKumar23 · Pull Request #11496 · ROCm/rocm-libraries

LakshmiKumar23 · 2026-08-31T17:17:38Z

Summary

This PR adds rocFFT library support for GPU-accelerated FFT in the RPP HIP backend audio spectrogram, replacing the O(N²) manual DFT implementation with O(N log N) rocFFT library calls. This is the GPU counterpart to PR #11146's CPU FFT work.

JIRA: AICV-283

Dependencies

⚠️ This PR depends on #11146 merging first. This branch includes the merge of PR #11146 to integrate the build system changes for dual FFT backend support (CPU: FFTS/in-house FFT, GPU: rocFFT/manual DFT).

Background

CPU Side (HOST Backend) - PR #11146

Before: Used external FFTS library (required dependency)
After: Added in-house CPU FFT algorithm, making FFTS optional

GPU Side (HIP Backend) - This PR

Before: Manual DFT implementation (O(N²) brute force using custom GPU kernels)
- Two kernels: compute_coefficients_hip_tensor + fourier_transform_hip_tensor
- Completely independent of FFTS library (separate code path)
After: rocFFT library acceleration (O(N log N))
- Single magnitude kernel + rocFFT library call
- Plan caching optimization for repeated transforms
- Manual DFT kept as conditional fallback

Key Note: CPU and GPU FFT implementations were always separate - this PR only touches the HIP backend.

Performance Results

Speedup: 1.6x over manual DFT implementation (with plan caching optimization)

Changes Made

1. CMake Infrastructure

New: projects/rpp/cmake/FindROCFFT.cmake - CMake finder module for rocFFT
- Searches TheRock paths and standard ROCm SDK locations
- Creates imported target rocfft::rocfft
Modified: projects/rpp/CMakeLists.txt
- Dual FFT backend support: CPU (FFTS/in-house) + HIP (rocFFT/manual DFT)
- Auto-detection with find_package(ROCFFT QUIET)
- Conditional compilation flag: -DRPP_USE_ROCFFT
- Conditional linking for HIP backend

2. Code Implementation

Modified: projects/rpp/src/modules/tensor/hip/kernel/spectrogram.cpp
- Added rocFFT execution path with #ifdef RPP_USE_ROCFFT
- New kernel: compute_magnitude_from_complex_hip_tensor
  - Converts rocFFT complex output to magnitude (power 1 or 2)
  - Optimized transpose path for FT layout using shared memory
- rocFFT workflow: plan creation → execution → magnitude computation
- Kept manual DFT as #else fallback (will be removed after validation period)

3. Performance Optimization

Modified: projects/rpp/src/include/rpp_handle.hpp
- Moved rocfft_setup()/cleanup() from per-call to Handle ctor/dtor
- Added rocFFT plan cache in HandleImpl (keyed by nfft size)
- Added get_rocfft_plan() helper for plan creation/retrieval
- Eliminates expensive plan recreation on every spectrogram call

4. Documentation

Modified: projects/rpp/CHANGELOG.md
- Added entry for rocFFT GPU acceleration with 1.6x speedup
- Documented in-house CPU FFT from PR (feat) (rpp) : Implement ffts functionality self contained in RPP #11146
- Bumped version to 3.3.0
Modified: projects/rpp/CMakeLists.txt
- Version bump: 3.2.0 → 3.3.0
- Audio support now enabled by default
Modified: projects/rpp/README.md and docs/install/rpp-build.rst
- Documented new FFT backend behavior
- Updated build instructions

Testing

Test Results

HIP Backend: ✅ PASSED
- All audio tests passed including spectrogram
- Golden reference validation successful

Test Coverage

✅ nfft sizes: 256, 512, 1024, 2048
✅ Batch sizes: 1, 3, 8, 16
✅ Layouts: TF (time-frequency) and FT (frequency-time)
✅ Parameters: centerWindows ON/OFF, reflectPadding ON/OFF

Build Validation

Works with both rocFFT present and absent:

# With rocFFT (GPU acceleration)
cmake .. -DBACKEND=HIP -DRPP_AUDIO_SUPPORT=ON
ldd librpp.so | grep rocfft  # ✅ Shows librocfft.so.0

# Without rocFFT (fallback to manual DFT)
cmake .. -DBACKEND=HIP -DRPP_AUDIO_SUPPORT=ON # rocFFT not found
# ✅ Builds successfully, uses manual DFT

Future Work

Phase 6: Manual DFT Removal (planned after 1-2 release cycles)

Remove compute_coefficients_hip_tensor and fourier_transform_hip_tensor kernels
Remove all #ifdef RPP_USE_ROCFFT conditional blocks
Make rocFFT a required dependency for HIP audio support
Expected: ~150 lines of code removed, simpler maintenance

Files Changed

New Files:

projects/rpp/cmake/FindROCFFT.cmake

Modified Files:

projects/rpp/CMakeLists.txt - FFT detection, linking, version bump
projects/rpp/src/modules/tensor/hip/kernel/spectrogram.cpp - rocFFT implementation
projects/rpp/src/include/rpp_handle.hpp - Plan caching
projects/rpp/CHANGELOG.md - Release notes
projects/rpp/README.md - Build documentation
projects/rpp/docs/install/rpp-build.rst - Build documentation

Checklist

Code follows project style guidelines
Tests pass on HIP backend
Performance benchmarking completed (1.6x speedup documented)
CHANGELOG.md updated
Version bumped (3.2.0 → 3.3.0)
Documentation updated
Depends on PR (feat) (rpp) : Implement ffts functionality self contained in RPP #11146 (noted in description)

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- Created FindROCFFT.cmake module for rocFFT library detection - Modified CMakeLists.txt to detect rocFFT for HIP backend - Enable audio support with either FFTS (CPU) or rocFFT (HIP) - Link rocFFT only for HIP backend, FFTS only for CPU backend - Set RPP_USE_ROCFFT_LIB=1 when rocFFT is found Co-Authored-By: Claude <noreply@anthropic.com>

Combined changes from users/rrawther/rpp_ffts_host_implementation with our rocFFT GPU implementation: - CPU backend: FFTS library OR in-house FFT (PR #11146) - HIP backend: rocFFT library (our addition) - Both backends now have library-accelerated FFT support - Resolved merge conflicts in CMakeLists.txt Co-Authored-By: Claude <noreply@anthropic.com>

- Fixed FindROCFFT.cmake to search for rocfft.h with PATH_SUFFIXES - Removed 'manual DFT' reference from rocFFT not found message - Verified: librpp.so successfully links librocfft.so.0 Co-Authored-By: Claude <noreply@anthropic.com>

Implements Phase 2 of rocFFT integration: code implementation in spectrogram.cpp Changes: - Add rocFFT header with conditional compilation guard - New kernel: compute_magnitude_from_complex_hip_tensor * Non-vertical: Direct coalesced writes (TF layout) * Vertical: 16x16 shared memory transpose (FT layout) * Supports power=1 (magnitude) and power=2 (squared) - Add rocFFT execution path in hip_exec_spectrogram_tensor * Real-to-complex 1D batch FFT using rocFFT library * Proper resource management and error handling * Specific RPP error codes for different failure scenarios - Preserve manual DFT code as fallback under #else Performance: rocFFT provides O(N log N) vs O(N^2) manual DFT Expected speedup: 3-30x depending on nfft size Build verification: - Clean compile with no warnings - librocfft.so.0 successfully linked - All rocFFT symbols present in librpp.so Co-Authored-By: Claude <noreply@anthropic.com>

Moves rocfft_setup() and rocfft_cleanup() from per-call (in spectrogram) to per-handle lifecycle (Handle constructor/destructor). Before: rocfft_setup/cleanup called on every spectrogram invocation After: Called once when Handle is created/destroyed Performance improvement: ~10% reduction in overhead (143ms → 128ms) Note: rocFFT plan creation/destruction still occurs per-call and is the main performance bottleneck (36x slower than manual DFT for small nfft=512). Future work: implement plan caching for better performance. Co-Authored-By: Claude <noreply@anthropic.com>

Cache rocFFT plans in Handle to avoid expensive plan creation/destruction on every spectrogram call. Plans are keyed by (nfft, batchCount) composite key and destroyed when the Handle is released. Performance improvement: spectrogram now runs 1.6x faster than manual DFT (2.11ms vs 3.37ms avg per batch). - Add rocfft_plan_cache map to HandleImpl (keyed by nfft << 32 | batchCount) - Add get_rocfft_plan() helper to create/retrieve cached plans - Fix namespace mismatch (declaration now in namespace rpp) - Fix AUDIO_SUPPORT preprocessor guard Co-Authored-By: Claude <noreply@anthropic.com>

- Bump version from 3.2.0 to 3.3.0 for rocFFT integration - Enable RPP_AUDIO_SUPPORT by default (no external FFT dependency) - Add changelog entry for rocFFT GPU acceleration and in-house CPU FFT - Update README and build docs to reflect new defaults and FFT backends Co-Authored-By: Claude <noreply@anthropic.com>

therock-pr-bot · 2026-08-31T17:22:30Z

✅ All Checks Passed — Ready for Review

Check	Status	Details
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🧪 Unit Test	⚠️ Warning	Error: Source/code files changed without an accompanying unit test. Expected: add at least one test file named like `test_<name>.py` / `test_<name>.cpp` (or `<name>_test.`). Current:* code file(s) changed: `projects/rpp/src/include/common/cpu/rpp_cpu_fft.hpp`, `projects/rpp/src/include/tensor/hip_tensor_executors.hpp`, `projects/rpp/src/modules/handle_hip.cpp`, `projects/rpp/src/modules/tensor/cpu/kernel/spectrogram.cpp`, `projects/rpp/src/modules/tensor/hip/kernel/spectrogram.cpp` (+1 more); no test file found
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- Reformat function signatures to meet line length requirements - Add blank line after include directives - Consolidate single-line if statements Co-Authored-By: Claude <noreply@anthropic.com>

- Break long comment lines - Reformat long assignment statements - Adjust hipMemsetAsync formatting Co-Authored-By: Claude <noreply@anthropic.com>

Apply clang-format to fix all remaining formatting issues: - Line length compliance - Proper indentation alignment - Consistent spacing Co-Authored-By: Claude <noreply@anthropic.com>

therock-pr-bot · 2026-08-31T17:51:15Z

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levxn and others added 14 commits August 6, 2026 05:34

Fix cutout_dropout/grid_dropout/erase to honor ROI offset when applyi…

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Merge branch 'develop' into users/levxn/fix-dropout-erase-partial-roi…

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implementation for ffts within RPP removing the dependancy on third_p…

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Merge remote-tracking branch 'origin/develop' into users/rrawther/rpp…

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merge with develop

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fix pre-commit failures

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LakshmiKumar23 self-assigned this Aug 31, 2026

github-actions Bot added documentation project: rpp labels Aug 31, 2026

LakshmiKumar23 added test_type:standard If enabled, the PR will run standard tests test:rpp and removed documentation labels Aug 31, 2026

assistant-librarian Bot added the organization: ROCm label Aug 31, 2026

Fix clang-format issues

bc26149

- Reformat function signatures to meet line length requirements - Add blank line after include directives - Consolidate single-line if statements Co-Authored-By: Claude <noreply@anthropic.com>

github-actions Bot added the documentation label Aug 31, 2026

LakshmiKumar23 and others added 2 commits August 31, 2026 10:40

Fix additional clang-format issues in spectrogram.cpp

a09cbfa

- Break long comment lines - Reformat long assignment statements - Adjust hipMemsetAsync formatting Co-Authored-By: Claude <noreply@anthropic.com>

Run clang-format on all modified files

07b00c5

Apply clang-format to fix all remaining formatting issues: - Line length compliance - Proper indentation alignment - Consistent spacing Co-Authored-By: Claude <noreply@anthropic.com>

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[RPP] Add rocFFT GPU acceleration for audio spectrogram (AICV-283) - #11496

[RPP] Add rocFFT GPU acceleration for audio spectrogram (AICV-283)#11496
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LakshmiKumar23 commented Aug 31, 2026

Summary

Dependencies

Background

CPU Side (HOST Backend) - PR #11146

GPU Side (HIP Backend) - This PR

Performance Results

Changes Made

1. CMake Infrastructure

2. Code Implementation

3. Performance Optimization

4. Documentation

Testing

Test Results

Test Coverage

Build Validation

Future Work

Files Changed

Checklist

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