| /** |
| * |
| * 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.bookkeeper.common.util.affinity.impl; |
| |
| import edu.umd.cs.findbugs.annotations.SuppressFBWarnings; |
| |
| import java.io.IOException; |
| import java.nio.charset.Charset; |
| import java.nio.charset.StandardCharsets; |
| import java.nio.file.Files; |
| import java.nio.file.Path; |
| import java.nio.file.Paths; |
| import java.nio.file.StandardOpenOption; |
| import java.util.SortedSet; |
| import java.util.TreeSet; |
| |
| import lombok.experimental.UtilityClass; |
| import lombok.extern.slf4j.Slf4j; |
| |
| import org.apache.commons.lang3.StringUtils; |
| |
| @UtilityClass |
| @Slf4j |
| class IsolatedProcessors { |
| |
| private static final Charset ENCODING = StandardCharsets.US_ASCII; |
| |
| private static final String ISOLATED_CPU_PATH = "/sys/devices/system/cpu/isolated"; |
| |
| @SuppressFBWarnings("DMI_HARDCODED_ABSOLUTE_FILENAME") |
| static SortedSet<Integer> get() throws IOException { |
| return parseProcessorRange(new String(Files.readAllBytes(Paths.get(ISOLATED_CPU_PATH)), ENCODING)); |
| } |
| |
| static SortedSet<Integer> parseProcessorRange(String range) { |
| SortedSet<Integer> processors = new TreeSet<>(); |
| |
| for (String part : StringUtils.trim(range).split(",")) { |
| if (part.contains("-")) { |
| // This is a range, eg: 1-5 with both edges included |
| String[] parts = part.split("-"); |
| int first = Integer.parseInt(parts[0]); |
| int last = Integer.parseInt(parts[1]); |
| |
| for (int i = first; i <= last; i++) { |
| processors.add(i); |
| } |
| } else if (!part.isEmpty()) { |
| processors.add(Integer.parseInt(part)); |
| } |
| } |
| |
| return processors; |
| } |
| |
| /** |
| * Instruct Linux to disable a particular CPU. This is used to disable hyper-threading on a particular core, by |
| * shutting down the cpu that shares the same core. |
| */ |
| static void disableCpu(int cpu) throws IOException { |
| changeCpuStatus(cpu, false); |
| } |
| |
| static void enableCpu(int cpu) throws IOException { |
| changeCpuStatus(cpu, true); |
| } |
| |
| /** |
| * Instruct Linux to disable a particular CPU. This is used to disable hyper-threading on a particular core, by |
| * shutting down the cpu that shares the same core. |
| */ |
| private static void changeCpuStatus(int cpu, boolean enable) throws IOException { |
| Path cpuPath = Paths.get(String.format("/sys/devices/system/cpu/cpu%d/online", cpu)); |
| |
| boolean currentState = Integer |
| .parseInt(StringUtils.trim(new String(Files.readAllBytes(cpuPath), ENCODING))) != 0; |
| |
| if (currentState != enable) { |
| Files.write(cpuPath, (enable ? "1\n" : "0\n").getBytes(ENCODING), StandardOpenOption.TRUNCATE_EXISTING); |
| log.info("{} CPU {}", enable ? "Enabled" : "Disabled", cpu); |
| } |
| } |
| } |