| // Copyright 2023 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.metrics; |
| |
| import static com.google.common.collect.ImmutableSetMultimap.toImmutableSetMultimap; |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| |
| import com.google.auto.value.AutoValue; |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.base.Splitter; |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.ImmutableSetMultimap; |
| import com.google.common.flogger.GoogleLogger; |
| import com.google.devtools.build.lib.clock.Clock; |
| import java.io.BufferedReader; |
| import java.io.IOException; |
| import java.io.InputStreamReader; |
| import java.time.Duration; |
| import java.time.Instant; |
| import java.util.List; |
| import java.util.function.Function; |
| |
| /** |
| * Helps to collect infomation about all process using ps command. Works for Linux and MacOS systems |
| */ |
| public class PsInfoCollector { |
| private static final GoogleLogger logger = GoogleLogger.forEnclosingClass(); |
| // Updates snapshots no more than once per interval. Running ps is somewhat slow and should not be |
| // done too often. |
| private static final Duration MIN_COLLECTION_INTERVAL = Duration.ofMillis(500); |
| private static final PsInfoCollector instance = new PsInfoCollector(); |
| |
| public static PsInfoCollector instance() { |
| return instance; |
| } |
| |
| private PsSnapshot currentPsSnapshot; |
| |
| // prevent construction |
| private PsInfoCollector() {} |
| |
| /** |
| * If ps snapshot was outdated will update it, and then returns resource consumption snapshot of |
| * processes subtrees based on collected ps snapshot. |
| */ |
| public synchronized ResourceSnapshot collectResourceUsage( |
| ImmutableSet<Long> processIds, Clock clock) { |
| Instant now = clock.now(); |
| if (currentPsSnapshot == null |
| || Duration.between(currentPsSnapshot.getCollectionTime(), now) |
| .compareTo(MIN_COLLECTION_INTERVAL) |
| > 0) { |
| |
| updatePsSnapshot(clock); |
| } |
| |
| ImmutableMap.Builder<Long, Integer> pidToMemoryInKb = ImmutableMap.builder(); |
| for (Long pid : processIds) { |
| PsInfo psInfo = currentPsSnapshot.getPidToPsInfo().get(pid); |
| if (psInfo == null) { |
| continue; |
| } |
| pidToMemoryInKb.put(pid, collectMemoryUsageOfDescendants(psInfo, currentPsSnapshot)); |
| } |
| |
| return ResourceSnapshot.create( |
| pidToMemoryInKb.buildOrThrow(), currentPsSnapshot.getCollectionTime()); |
| } |
| |
| /** Updates current snapshot of all processes state, using ps command. */ |
| private void updatePsSnapshot(Clock clock) { |
| // TODO(b/279003887): add exception if we couldn't collect the metrics. |
| ImmutableMap<Long, PsInfo> pidToPsInfo = collectDataFromPs(); |
| |
| ImmutableSetMultimap<Long, PsInfo> pidToChildrenPsInfo = |
| pidToPsInfo.values().stream() |
| .collect(toImmutableSetMultimap(PsInfo::getParentPid, Function.identity())); |
| |
| currentPsSnapshot = PsSnapshot.create(pidToPsInfo, pidToChildrenPsInfo, clock.now()); |
| } |
| |
| /** Collects memory usage for every process. */ |
| @VisibleForTesting |
| ImmutableMap<Long, PsInfo> collectDataFromPs() { |
| try { |
| Process psProcess = buildPsProcess(); |
| return collectDataFromPsProcess(psProcess); |
| } catch (IOException e) { |
| logger.atWarning().withCause(e).log("Error while executing command ps"); |
| return ImmutableMap.of(); |
| } |
| } |
| |
| static ImmutableMap<Long, PsInfo> collectDataFromPsProcess(Process psProcess) { |
| BufferedReader psOutput = |
| new BufferedReader(new InputStreamReader(psProcess.getInputStream(), UTF_8)); |
| |
| ImmutableMap.Builder<Long, PsInfo> psInfos = ImmutableMap.builder(); |
| |
| try { |
| // The output of the above ps command looks similar to this: |
| // PID PPID RSS |
| // 211706 1 222972 |
| // 2612333 211706 6180 |
| // We skip over the first line (the header) and then parse the PID and the resident memory |
| // size in kilobytes. |
| String output = null; |
| boolean isFirst = true; |
| while ((output = psOutput.readLine()) != null) { |
| if (isFirst) { |
| isFirst = false; |
| continue; |
| } |
| List<String> line = Splitter.on(" ").trimResults().omitEmptyStrings().splitToList(output); |
| if (line.size() != 3) { |
| logger.atWarning().log("Unexpected length of split line %s %d", output, line.size()); |
| continue; |
| } |
| |
| long pid = Long.parseLong(line.get(0)); |
| long parentPid = Long.parseLong(line.get(1)); |
| int memoryInKb = Integer.parseInt(line.get(2)); |
| |
| psInfos.put(pid, PsInfo.create(pid, parentPid, memoryInKb)); |
| } |
| } catch (IllegalArgumentException | IOException e) { |
| logger.atWarning().withCause(e).log("Error while parsing psOutput: %s", psOutput); |
| } |
| |
| return psInfos.buildOrThrow(); |
| } |
| |
| private static Process buildPsProcess() throws IOException { |
| return new ProcessBuilder("ps", "-e", "-o", "pid,ppid,rss").start(); |
| } |
| |
| /** Recursively collects total memory usage of all descendants of the process. */ |
| private static int collectMemoryUsageOfDescendants(PsInfo psInfo, PsSnapshot psSnapshot) { |
| int currentMemoryInKb = psInfo.getMemoryInKb(); |
| for (PsInfoCollector.PsInfo childrenPsInfo : |
| psSnapshot.getPidToChildrenPsInfo().get(psInfo.getPid())) { |
| currentMemoryInKb += collectMemoryUsageOfDescendants(childrenPsInfo, psSnapshot); |
| } |
| |
| return currentMemoryInKb; |
| } |
| |
| /** Parsed information about process collected after ps command call. */ |
| @AutoValue |
| abstract static class PsInfo { |
| public abstract long getPid(); |
| |
| public abstract long getParentPid(); |
| |
| public abstract int getMemoryInKb(); |
| |
| public static PsInfo create(long pid, long parentPid, int memoryinKb) { |
| return new AutoValue_PsInfoCollector_PsInfo(pid, parentPid, memoryinKb); |
| } |
| } |
| |
| /** Contains structurized information from ps command. */ |
| @AutoValue |
| abstract static class PsSnapshot { |
| abstract ImmutableMap<Long, PsInfo> getPidToPsInfo(); |
| |
| abstract ImmutableSetMultimap<Long, PsInfo> getPidToChildrenPsInfo(); |
| |
| abstract Instant getCollectionTime(); |
| |
| static PsSnapshot create( |
| ImmutableMap<Long, PsInfo> pidToPsInfo, |
| ImmutableSetMultimap<Long, PsInfo> pidToChildrenPsInfo, |
| Instant collectionTime) { |
| return new AutoValue_PsInfoCollector_PsSnapshot( |
| pidToPsInfo, pidToChildrenPsInfo, collectionTime); |
| } |
| } |
| } |