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project_6/cccl_upstream/cub/benchmarks/bench/scan/exclusive/base.cuh
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) 2011-2026, NVIDIA CORPORATION. All rights reserved.
// SPDX-License-Identifier: BSD-3
#pragma once
#include <cub/device/device_scan.cuh>
#include <cuda/std/__functional/invoke.h>
#include <nvbench_helper.cuh>
#include "../policy_selector.h"
template <typename T, typename OffsetT>
static void basic(nvbench::state& state, nvbench::type_list<T, OffsetT>)
try
{
using init_value_t = T;
using accum_t [[maybe_unused]] = ::cuda::std::__accumulator_t<op_t, init_value_t, T>;
using offset_t = cub::detail::choose_offset_t<OffsetT>;
#if USES_LOOKAHEAD()
static_assert(sizeof(offset_t) == sizeof(size_t)); // lookahead scan uses size_t internally
#endif // USES_LOOKAHEAD()
const auto elements = static_cast<std::size_t>(state.get_int64("Elements{io}"));
if (sizeof(offset_t) == 4 && elements > std::numeric_limits<offset_t>::max())
{
state.skip("Skipping: input size exceeds 32-bit offset type capacity.");
return;
}
thrust::device_vector<T> input = generate(elements);
thrust::device_vector<T> output(elements);
const T* d_input = thrust::raw_pointer_cast(input.data());
T* d_output = thrust::raw_pointer_cast(output.data());
state.add_element_count(elements);
state.add_global_memory_reads<T>(elements, "Size");
state.add_global_memory_writes<T>(elements);
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
#if !TUNE_BASE
,
cuda::execution::tune(policy_selector<accum_t>{})
#endif // !TUNE_BASE
);
_CCCL_TRY_CUDA_API(
cub::DeviceScan::ExclusiveScan,
"ExclusiveScan failed",
d_input,
d_output,
op_t{},
init_value_t{},
static_cast<offset_t>(input.size()),
env);
});
}
catch (const std::bad_alloc&)
{
state.skip("Skipping: out of memory.");
}
// __half and __nv_bfloat16 are added for full (non-tuning) runs; CUB has fast paths for them (see #9587).
#ifdef TUNE_T
using value_types = nvbench::type_list<TUNE_T>;
#else
using value_types =
push_back_t<all_types
# if _CCCL_HAS_NVFP16() && _CCCL_CTK_AT_LEAST(12, 2)
,
__half
# endif
# if _CCCL_HAS_NVBF16() && _CCCL_CTK_AT_LEAST(12, 2)
,
__nv_bfloat16
# endif
>;
#endif
NVBENCH_BENCH_TYPES(basic, NVBENCH_TYPE_AXES(value_types, scan_offset_types))
.set_name("base")
.set_type_axes_names({"T{ct}", "OffsetT{ct}"})
.add_int64_power_of_two_axis("Elements{io}", nvbench::range(16, 32, 4));