Prepare select and partition tuning policies for lookahead

[bernhardmgruber]

Fixes part of: #10075

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between 4874f7f and 4c7f2cd.

📒 Files selected for processing (12)

• cub/benchmarks/bench/partition/flagged.cu
• cub/benchmarks/bench/partition/if.cu
• cub/benchmarks/bench/select/flagged.cu
• cub/benchmarks/bench/select/if.cu
• cub/benchmarks/bench/select/unique.cu
• cub/cub/device/device_partition.cuh
• cub/cub/device/dispatch/dispatch_select_if.cuh
• cub/cub/device/dispatch/tuning/tuning_select_if.cuh
• cub/test/catch2_test_device_partition_env.cu
• cub/test/catch2_test_device_partition_env_api.cu
• cub/test/catch2_test_device_select_env.cu
• cub/test/catch2_test_device_select_env_api.cu

🚧 Files skipped from review as they are similar to previous changes (10)

• cub/cub/device/device_partition.cuh
• cub/benchmarks/bench/select/flagged.cu
• cub/test/catch2_test_device_select_env_api.cu
• cub/benchmarks/bench/partition/flagged.cu
• cub/test/catch2_test_device_partition_env_api.cu
• cub/cub/device/dispatch/dispatch_select_if.cuh
• cub/benchmarks/bench/select/if.cu
• cub/benchmarks/bench/select/unique.cu
• cub/test/catch2_test_device_partition_env.cu
• cub/cub/device/dispatch/tuning/tuning_select_if.cuh

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📝 Walkthrough

Summary by CodeRabbit

• Refactor

  • Updated selection and partition tuning policies to explicitly use the lookback algorithm.
  • Reorganized lookback-related tuning parameters under a nested configuration for clearer, consistent policy construction.
  • Improved policy equality/comparison and string formatting to reflect the new structure.

• Tests

  • Updated device tuning and validation tests, including expected policy descriptions, to match the nested policy layout.
  • Adjusted benchmark policy construction to use the explicit lookback algorithm selection.

Walkthrough

Changes

Lookback tuning policies now use explicit algorithm discriminators and nested payload structs. Device dispatch, benchmarks, and tests are updated to construct and consume the new SelectPolicy and PartitionPolicy layouts.

Suggested labels: libcu++

Suggested reviewers: oleksandr-pavlyk, pauleonix

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[oleksandr-pavlyk]

Generating Doxygen XML...
/home/runner/_work/cccl/cccl/cub/cub/device/dispatch/tuning/tuning_select_if.cuh:72: error: unable to resolve reference to 'DeviceSelect' for \ref command
/home/runner/_work/cccl/cccl/cub/cub/device/dispatch/tuning/tuning_select_if.cuh:72: error: unable to resolve reference to 'DeviceSelect' for \ref command
Error: one or more Doxygen builds failed (see warnings above)

The line 72 reads:

72: //! The selection algorithm used by @ref DeviceSelect

but earlier line 37 seem to be using exact same thing without triggering error:

37: //! The lookback tuning policy for all non-ByKey algorithms in @ref DeviceSelect

[github-actions]

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