jiangjiguang commented on code in PR #1011: URL: https://github.com/apache/parquet-mr/pull/1011#discussion_r1115471862
########## parquet-column/src/main/java/org/apache/parquet/column/values/bitpacking/ParquetReadRouter.java: ########## @@ -0,0 +1,133 @@ +/* + * 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. + */ +package org.apache.parquet.column.values.bitpacking; + +import org.apache.parquet.bytes.ByteBufferInputStream; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.EOFException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.nio.file.Paths; +import java.util.Arrays; +import java.util.List; +import java.util.Set; +import java.util.stream.Collectors; + +/** + * Utility class for big data applications (such as Apache Spark and Apache Flink). + * For Intel CPU, Flags containing avx512vbmi and avx512_vbmi2 can have better performance gains. + */ +public class ParquetReadRouter { + private static final Logger LOG = LoggerFactory.getLogger(ParquetReadRouter.class); + + private static final int BITS_PER_BYTE = 8; + + // register of avx512 are 512 bits, and can load up to 64 bytes + private static final int BYTES_PER_VECTOR_512 = 64; + + // values are bit packed 8 at a time, so reading bitWidth will always work + private static final int NUM_VALUES_TO_PACK = 8; + + private static final VectorSupport vectorSupport; + + static { + vectorSupport = getSupportVectorFromCPUFlags(); + } + + // Dispatches to use vector when available. Directly call readBatchUsing512Vector() if you are sure about it. + public static void read(int bitWidth, ByteBufferInputStream in, int currentCount, int[] currentBuffer) throws IOException { + switch (vectorSupport) { + case VECTOR_512: + readBatchUsing512Vector(bitWidth, in, currentCount, currentBuffer); + break; + default: + readBatch(bitWidth, in, currentCount, currentBuffer); + } + } + + // Call the method directly if your computer system contains avx512vbmi and avx512_vbmi2 CPU Flags + public static void readBatchUsing512Vector(int bitWidth, ByteBufferInputStream in, int currentCount, int[] currentBuffer) throws IOException { + BytePacker packer = Packer.LITTLE_ENDIAN.newBytePacker(bitWidth); + BytePacker packerVector = Packer.LITTLE_ENDIAN.newBytePackerVector(bitWidth); + int valueIndex = 0; + int byteIndex = 0; + int unpackCount = packerVector.getUnpackCount(); + int inputByteCountPerVector = packerVector.getUnpackCount() / BITS_PER_BYTE * bitWidth; + int totalByteCount = currentCount * bitWidth / BITS_PER_BYTE; + int totalByteCountVector = totalByteCount - BYTES_PER_VECTOR_512; + ByteBuffer buffer = in.slice(totalByteCount); + if (buffer.hasArray()) { + for (; byteIndex < totalByteCountVector; byteIndex += inputByteCountPerVector, valueIndex += unpackCount) { + packerVector.unpackValuesUsingVector(buffer.array(), buffer.arrayOffset() + buffer.position() + byteIndex, currentBuffer, valueIndex); + } + // If the remaining bytes size <= {BYTES_PER_512VECTOR}, the remaining bytes are unpacked by packer + for (; byteIndex < totalByteCount; byteIndex += bitWidth, valueIndex += NUM_VALUES_TO_PACK) { + packer.unpack8Values(buffer.array(), buffer.arrayOffset() + buffer.position() + byteIndex, currentBuffer, valueIndex); + } + } else { + for (; byteIndex < totalByteCountVector; byteIndex += inputByteCountPerVector, valueIndex += unpackCount) { + packerVector.unpackValuesUsingVector(buffer, buffer.position() + byteIndex, currentBuffer, valueIndex); + } + for (; byteIndex < totalByteCount; byteIndex += bitWidth, valueIndex += NUM_VALUES_TO_PACK) { + packer.unpack8Values(buffer, buffer.position() + byteIndex, currentBuffer, valueIndex); + } + } + } + + // Call the method directly if your computer system doesn't contain avx512vbmi and avx512_vbmi2 CPU Flags + public static void readBatch(int bitWidth, ByteBufferInputStream in, int currentCount, int[] currentBuffer) throws EOFException { + BytePacker packer = Packer.LITTLE_ENDIAN.newBytePacker(bitWidth); + int valueIndex = 0; + while (valueIndex < currentCount) { + ByteBuffer buffer = in.slice(bitWidth); + packer.unpack8Values(buffer, buffer.position(), currentBuffer, valueIndex); + valueIndex += NUM_VALUES_TO_PACK; + } + } + + private static VectorSupport getSupportVectorFromCPUFlags() { + try { + String os = System.getProperty("os.name"); + if (os == null || !os.toLowerCase().startsWith("linux")) { + return VectorSupport.NONE; + } + List<String> allLines = Files.readAllLines(Paths.get("/proc/cpuinfo"), StandardCharsets.UTF_8); + for (String line : allLines) { + if (line != null && line.startsWith("flags")) { + int index = line.indexOf(":"); + if (index < 0) { + continue; + } + line = line.substring(index + 1); + Set<String> flagsSet = Arrays.stream(line.split(" ")).collect(Collectors.toSet()); + if (flagsSet.contains("avx512vbmi") && flagsSet.contains("avx512_vbmi2")) { + return VectorSupport.VECTOR_512; + } + } + } Review Comment: @gszadovszky Even though the java vector API can check the CPU Flags(low level check), but if users use java vector api on computer which dose not contain avx512vbmi && avx512_vbmi2, the java vector API how to do ? throw exception? fall back ? Besides, the CPU Flags are becoming more and more, and Java vector api is also increasing. maybe Java vector api dose not know which CPU Flags the users need. I think users should have already known their computer(including CPU Flags). They can decide whether to enable parquet java17 vector optimization. We only need show what CPU Flags needed in README.md For example, velox(https://github.com/facebookincubator/velox) shows only what CPU Flags needed.  -- 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: dev-unsubscr...@parquet.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
