pitrou commented on code in PR #46963: URL: https://github.com/apache/arrow/pull/46963#discussion_r2191998662
########## cpp/src/arrow/util/byte_stream_split_internal.cc: ########## @@ -0,0 +1,124 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#include "arrow/util/byte_stream_split_internal.h" +#include "arrow/util/dispatch_internal.h" + +#include <array> + +namespace arrow::util::internal { + +using ::arrow::internal::DispatchLevel; +using ::arrow::internal::DynamicDispatch; + +/************************ + * Decode dispatching * + ************************/ + +template <int kNumStreams> +struct ByteStreamSplitDecodeDynamic { + using FunctionType = decltype(&ByteStreamSplitDecodeScalar<kNumStreams>); + using Implementation = std::pair<DispatchLevel, FunctionType>; + + constexpr static auto implementations() { + return std::array { + Implementation { + DispatchLevel::NONE, +#if defined(ARROW_HAVE_NEON) + // We always expect Neon to be available on Arm64 + &ByteStreamSplitDecodeSimd<xsimd::neon64, kNumStreams>, +#elif defined(ARROW_HAVE_SSE4_2) + // We always expect SSE4.2 to be available on x86_64 + &ByteStreamSplitDecodeSimd<xsimd::sse4_2, kNumStreams>, +#else + &ByteStreamSplitDecodeScalar<kNumStreams>, +#endif + } + , +#if defined(ARROW_HAVE_RUNTIME_AVX2) + Implementation{ + DispatchLevel::AVX2, + &ByteStreamSplitDecodeSimd<xsimd::avx2, kNumStreams>, + }, +#endif + }; + } +}; + +template <int kNumStreams> +void ByteStreamSplitDecodeSimdDispatch(const uint8_t* data, int width, int64_t num_values, + int64_t stride, uint8_t* out) { + static const DynamicDispatch<ByteStreamSplitDecodeDynamic<kNumStreams>> dispatch; + return dispatch.func(data, width, num_values, stride, out); +} + +template void ByteStreamSplitDecodeSimdDispatch<2>(const uint8_t*, int, int64_t, int64_t, + uint8_t*); +template void ByteStreamSplitDecodeSimdDispatch<4>(const uint8_t*, int, int64_t, int64_t, + uint8_t*); +template void ByteStreamSplitDecodeSimdDispatch<8>(const uint8_t*, int, int64_t, int64_t, + uint8_t*); + +/************************ + * Encode dispatching * + ************************/ + +template <int kNumStreams> +struct ByteStreamSplitEncodeDynamic { + using FunctionType = decltype(&ByteStreamSplitEncodeScalar<kNumStreams>); + using Implementation = std::pair<DispatchLevel, FunctionType>; + + constexpr static auto implementations() { + return std::array { + // Limited interest for performance on builds without a minimum SIMD level + // So we put SSE4.2 and NEON as a base level. Review Comment: Let's remove this comment as it's not the actual reason. ```suggestion ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
