com.google.devtools.build.lib.actions.LocalHostResourceManagerLinux.java Source code

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Here is the source code for com.google.devtools.build.lib.actions.LocalHostResourceManagerLinux.java

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// Copyright 2016 The Bazel Authors. All rights reserved.
//
// Licensed 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 com.google.devtools.build.lib.actions;

import com.google.common.base.Splitter;
import com.google.common.io.Files;
import com.google.devtools.build.lib.unix.ProcMeminfoParser;
import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.HashSet;
import java.util.Set;

/**
 * This class estimates the local host's resource capacity for Linux.
 */
public class LocalHostResourceManagerLinux {
    private static String cpuInfoContent = null;

    private static final Splitter NEWLINE_SPLITTER = Splitter.on('\n').omitEmptyStrings();
    private static final String CPU_INFO_FILE = "/proc/cpuinfo";
    private static final String MEM_INFO_FILE = "/proc/meminfo";

    private static int getLogicalCpuCount() throws IOException {
        String content = getCpuInfoContent();
        return getLogicalCpuCountHelper(content);
    }

    private static int getPhysicalCpuCount(int logicalCpuCount) throws IOException {
        String content = getCpuInfoContent();
        return getPhysicalCpuCountHelper(logicalCpuCount, content);
    }

    private static double getMemoryInMb() throws IOException {
        return getMemoryInMbHelper(MEM_INFO_FILE);
    }

    public static ResourceSet getLocalHostResources() {
        try {
            int logicalCpuCount = getLogicalCpuCount();
            int physicalCpuCount = getPhysicalCpuCount(logicalCpuCount);
            double ramMb = getMemoryInMb();

            boolean hyperthreading = (logicalCpuCount != physicalCpuCount);
            final double EFFECTIVE_CPUS_PER_HYPERTHREADED_CPU = 0.6;
            return ResourceSet.create(ramMb,
                    logicalCpuCount * (hyperthreading ? EFFECTIVE_CPUS_PER_HYPERTHREADED_CPU : 1.0), 1.0,
                    Integer.MAX_VALUE);
        } catch (IOException | IllegalArgumentException e) {
            return null;
        }
    }

    private static String getCpuInfoContent() throws IOException {
        if (cpuInfoContent == null) {
            cpuInfoContent = readContent(CPU_INFO_FILE);
        }
        return cpuInfoContent;
    }

    private static String readContent(String filename) throws IOException {
        return Files.toString(new File(filename), Charset.defaultCharset());
    }

    /**
     * For testing purposes only. Do not use it.
     */
    public static int getLogicalCpuCountHelper(String content) throws IOException {
        int count = 0;
        Iterable<String> lines = NEWLINE_SPLITTER.split(content);
        for (String line : lines) {
            if (line.startsWith("processor")) {
                count++;
            }
        }
        if (count == 0) {
            throw new IllegalArgumentException("Can't get logical CPU count");
        }
        return count;
    }

    public static int getPhysicalCpuCountHelper(int logicalCpuCount, String content) throws IOException {
        // CPU count
        Iterable<String> lines = NEWLINE_SPLITTER.split(content);
        Set<String> uniq = new HashSet<>();
        for (String line : lines) {
            if (line.startsWith("physical id")) {
                uniq.add(line);
            }
        }
        int cpuCount = uniq.size();
        if (cpuCount == 0) {
            cpuCount = logicalCpuCount;
        }

        // core per CPU
        uniq = new HashSet<>();
        for (String line : lines) {
            if (line.startsWith("core id")) {
                uniq.add(line);
            }
        }
        int coresPerCpu = uniq.size();
        if (coresPerCpu == 0) {
            coresPerCpu = 1;
        }

        return cpuCount * coresPerCpu;
    }

    public static double getMemoryInMbHelper(String memInfoFileName) throws IOException {
        ProcMeminfoParser memInfo = new ProcMeminfoParser(memInfoFileName);
        double ramMb = ProcMeminfoParser.kbToMb(memInfo.getTotalKb());
        return ramMb;
    }
}