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project_6/cccl_upstream/cub/benchmarks/bench/reduce/deterministic.cu
EngineX CI 56fd68e7dd [INFRA] Import NVIDIA/CCCL upstream as optimization reference library
CCCL (CUDA C++ Core Libraries) provides:
- CUB: device/block/warp-level GPU primitives (reduce, scan, sort, topk)
- Thrust: high-level parallel algorithms (transform_reduce, sort, scan)
- libcudacxx: CUDA C++ standard library (atomics, barriers, memory)
- cudax: experimental features (memory resources, allocators)
- Tuning policies: per-SM hardware-specific algorithm parameters

Competition optimization vectors mapped to CCCL:
- Output TPS (83% weight): warp_reduce, block_reduce, device_topk
- Input TPS (14% weight): device_scan, block_load, prefetch
- Cache TPS (3% weight): prefix caching strategy patterns
- Memory (0.9 util): pooled/cached/buddy allocators

Source: https://github.com/NVIDIA/cccl (shallow clone, HEAD only)
License: Apache-2.0
2026-07-30 09:35:51 +00:00

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// SPDX-FileCopyrightText: Copyright (c) 2026, NVIDIA CORPORATION. All rights reserved.
// SPDX-License-Identifier: BSD-3
#include <cub/device/device_reduce.cuh>
#include <cuda/execution.determinism.h>
#include <cuda/execution.require.h>
#include <cuda/std/utility>
#include <nvbench_helper.cuh>
#include <nvbench/range.cuh>
#include <nvbench/types.cuh>
// %RANGE% TUNE_ITEMS_PER_THREAD ipt 3:24:1
// %RANGE% TUNE_THREADS_PER_BLOCK tpb 128:1024:32
#if !TUNE_BASE
struct policy_selector_t
{
[[nodiscard]] _CCCL_HOST_DEVICE constexpr auto operator()(cuda::compute_capability) const -> cub::ReducePolicy
{
const auto p = cub::ReducePassPolicy{
TUNE_THREADS_PER_BLOCK, TUNE_ITEMS_PER_THREAD, 1, cub::BLOCK_REDUCE_RAKING, cub::LOAD_DEFAULT};
return {p, p};
}
};
#endif // !TUNE_BASE
template <class T, class OffsetT>
void deterministic_sum(nvbench::state& state, nvbench::type_list<T, OffsetT>)
try
{
using init_value_t = T;
if (!cuda::std::in_range<OffsetT>(state.get_int64("Elements{io}")))
{
state.skip("Skipping: Elements{io} is not representable by OffsetT.");
return;
}
const auto elements = static_cast<OffsetT>(state.get_int64("Elements{io}"));
thrust::device_vector<T> in = generate(elements);
thrust::device_vector<T> out(1);
const T* d_in = thrust::raw_pointer_cast(in.data());
T* d_out = thrust::raw_pointer_cast(out.data());
state.add_element_count(elements);
state.add_global_memory_reads<T>(elements, "Size");
state.add_global_memory_writes<T>(out.size());
caching_allocator_t alloc;
state.exec(nvbench::exec_tag::gpu | nvbench::exec_tag::no_batch, [&](nvbench::launch& launch) {
auto env = cub_bench_env(
alloc,
launch,
cuda::execution::require(cuda::execution::determinism::gpu_to_gpu)
#if !TUNE_BASE
,
cuda::execution::tune(policy_selector_t{})
#endif // !TUNE_BASE
);
_CCCL_TRY_CUDA_API(
cub::DeviceReduce::Reduce, "Reduce failed", d_in, d_out, elements, cuda::std::plus<>{}, init_value_t{}, env);
});
}
catch (const std::bad_alloc&)
{
state.skip("Skipping: out of memory.");
}
using types = nvbench::type_list<float, double>;
NVBENCH_BENCH_TYPES(deterministic_sum, NVBENCH_TYPE_AXES(types, offset_types))
.set_name("base")
.set_type_axes_names({"T{ct}", "OffsetT{ct}"})
// 2^32 exceeds INT32_MAX to cover the code paths for problem sizes that exceed a single 32-bit chunk
.add_int64_power_of_two_axis("Elements{io}", {16, 20, 24, 28, 32});