[GitHub] [parquet-mr] gszadovszky commented on a diff in pull request #1011: PARQUET-2159: java17 vector parquet bit-packing decode optimization

["gszadovszky (via GitHub)" <gi...@apache.org>]

gszadovszky commented on code in PR #1011:
URL: https://github.com/apache/parquet-mr/pull/1011#discussion_r1107005376


##########
parquet-generator/src/main/java/org/apache/parquet/encoding/vectorbitpacking/BitPackingGenerator512Vector.java:
##########
@@ -0,0 +1,67 @@
+/*
+ * 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.encoding.vectorbitpacking;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * This class generates vector bit packers that pack the most significant bit first.
+ * The result of the generation is checked in. To regenerate the code run this class and check in the result.
+ */
+public class BitPackingGenerator512Vector {
+  private static final String CLASS_NAME_PREFIX_FOR_INT = "ByteBitPacking512Vector";
+  private static final String CLASS_NAME_PREFIX_FOR_LONG = "ByteBitPacking512VectorForLong";
+
+  public static void main(String[] args) throws Exception {
+    String basePath = args[0];
+    //TODO: Int for Big Endian
+    //generateScheme(false, true, basePath);
+
+    // Int for Little Endian
+    generateScheme(false, false, basePath);
+
+    //TODO: Long for Big Endian
+    //generateScheme(true, true, basePath);
+
+    //TODO: Long for Little Endian
+    //generateScheme(true, false, basePath);

Review Comment:
   When do we want to implement these TODOs? If it is not for an already upcoming change to address, I would suggest having more detailed descriptions here. Why do we need these? In what circumstances would it couse issues if we do not implement them?



##########
parquet-generator/src/main/java/org/apache/parquet/encoding/vectorbitpacking/BitPackingGenerator512Vector.java:
##########
@@ -0,0 +1,67 @@
+/*
+ * 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.encoding.vectorbitpacking;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * This class generates vector bit packers that pack the most significant bit first.
+ * The result of the generation is checked in. To regenerate the code run this class and check in the result.
+ */

Review Comment:
   Is this comment still stands? I cannot find the generated file checked in. BTW, I don't think it is a good practice to check in generated files. It is better to automatically generate them in `generate-sources` phase and then compile them with the other source files.



##########
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:
   It looks like quite hacky. Doesn't the vector API support this somehow?



##########
parquet-generator/src/main/java/org/apache/parquet/encoding/vectorbitpacking/BitPackingGenerator512Vector.java:
##########
@@ -0,0 +1,67 @@
+/*
+ * 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.encoding.vectorbitpacking;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * This class generates vector bit packers that pack the most significant bit first.
+ * The result of the generation is checked in. To regenerate the code run this class and check in the result.
+ */
+public class BitPackingGenerator512Vector {
+  private static final String CLASS_NAME_PREFIX_FOR_INT = "ByteBitPacking512Vector";
+  private static final String CLASS_NAME_PREFIX_FOR_LONG = "ByteBitPacking512VectorForLong";
+
+  public static void main(String[] args) throws Exception {
+    String basePath = args[0];
+    //TODO: Int for Big Endian
+    //generateScheme(false, true, basePath);
+
+    // Int for Little Endian
+    generateScheme(false, false, basePath);
+
+    //TODO: Long for Big Endian
+    //generateScheme(true, true, basePath);
+
+    //TODO: Long for Little Endian
+    //generateScheme(true, false, basePath);
+  }
+
+  private static void generateScheme(boolean isLong, boolean msbFirst,

Review Comment:
   I do not really get how this generation works. Some description would be great.



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