Remove incremental heuristic from workers, as it was not really useful.

--
MOS_MIGRATED_REVID=115800229

1 files changed, 7 insertions, 47 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java b/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
index e2b99beee3..3433e98706 100644
--- a/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
+++ b/src/main/java/com/google/devtools/build/lib/worker/WorkerSpawnStrategy.java
@@ -18,8 +18,6 @@ import static java.nio.charset.StandardCharsets.UTF_8;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
-import com.google.common.eventbus.EventBus;
-import com.google.common.eventbus.Subscribe;
 import com.google.common.hash.HashCode;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;
@@ -28,7 +26,6 @@ import com.google.devtools.build.lib.actions.ActionInput;
 import com.google.devtools.build.lib.actions.ActionInputFileCache;
 import com.google.devtools.build.lib.actions.ActionInputHelper;
 import com.google.devtools.build.lib.actions.ActionStatusMessage;
-import com.google.devtools.build.lib.actions.ChangedFilesMessage;
 import com.google.devtools.build.lib.actions.ExecException;
 import com.google.devtools.build.lib.actions.ExecutionStrategy;
 import com.google.devtools.build.lib.actions.Executor;
@@ -37,7 +34,6 @@ import com.google.devtools.build.lib.actions.SpawnActionContext;
 import com.google.devtools.build.lib.actions.UserExecException;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.concurrent.ThreadSafety;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.events.EventHandler;
 import com.google.devtools.build.lib.standalone.StandaloneSpawnStrategy;
@@ -55,16 +51,16 @@ import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * A spawn action context that launches Spawns the first time they are used in a persistent mode and
  * then shards work over all the processes.
  */
-@ExecutionStrategy(name = { "worker" }, contextType = SpawnActionContext.class)
-final class WorkerSpawnStrategy implements SpawnActionContext {
-  public static final String REASON_HEURISTIC =
-      "Not using worker strategy, because incrementalHeuristic says no";
+@ExecutionStrategy(
+  name = {"worker"},
+  contextType = SpawnActionContext.class
+)
+public final class WorkerSpawnStrategy implements SpawnActionContext {
   public static final String REASON_NO_FLAGFILE =
       "Not using worker strategy, because last argument does not contain a @flagfile";
   public static final String REASON_NO_TOOLS =
@@ -72,8 +68,6 @@ final class WorkerSpawnStrategy implements SpawnActionContext {
 
   private final Path execRoot;
   private final WorkerPool workers;
-  private final IncrementalHeuristic incrementalHeuristic;
-  private final StandaloneSpawnStrategy standaloneStrategy;
   private final WorkerOptions options;
   private final boolean verboseFailures;
   private final int maxRetries;
@@ -81,16 +75,12 @@ final class WorkerSpawnStrategy implements SpawnActionContext {
   public WorkerSpawnStrategy(
       BlazeDirectories blazeDirs,
       OptionsClassProvider optionsProvider,
-      EventBus eventBus,
       WorkerPool workers,
       boolean verboseFailures,
       int maxRetries) {
     Preconditions.checkNotNull(optionsProvider);
     this.options = optionsProvider.getOptions(WorkerOptions.class);
-    this.incrementalHeuristic = new IncrementalHeuristic(options.workerMaxChangedFiles);
-    eventBus.register(incrementalHeuristic);
     this.workers = Preconditions.checkNotNull(workers);
-    this.standaloneStrategy = new StandaloneSpawnStrategy(blazeDirs.getExecRoot(), verboseFailures);
     this.execRoot = blazeDirs.getExecRoot();
     this.verboseFailures = verboseFailures;
     this.maxRetries = maxRetries;
@@ -101,6 +91,8 @@ final class WorkerSpawnStrategy implements SpawnActionContext {
       throws ExecException, InterruptedException {
     Executor executor = actionExecutionContext.getExecutor();
     EventHandler eventHandler = executor.getEventHandler();
+    StandaloneSpawnStrategy standaloneStrategy =
+        Preconditions.checkNotNull(executor.getContext(StandaloneSpawnStrategy.class));
 
     if (executor.reportsSubcommands()) {
       executor.reportSubcommand(
@@ -111,14 +103,6 @@ final class WorkerSpawnStrategy implements SpawnActionContext {
           spawn.asShellCommand(executor.getExecRoot()));
     }
 
-    if (!incrementalHeuristic.shouldUseWorkers()) {
-      if (options.workerVerbose) {
-        eventHandler.handle(Event.info(REASON_HEURISTIC));
-      }
-      standaloneStrategy.exec(spawn, actionExecutionContext);
-      return;
-    }
-
     // We assume that the spawn to be executed always gets a @flagfile argument, which contains the
     // flags related to the work itself (as opposed to start-up options for the executed tool).
     // Thus, we can extract the last element from its args (which will be the @flagfile), expand it
@@ -285,28 +269,4 @@ final class WorkerSpawnStrategy implements SpawnActionContext {
   public boolean willExecuteRemotely(boolean remotable) {
     return false;
   }
-
-  /**
-   * For installation with remote execution, non-incremental builds may be slowed down by the
-   * persistent worker system. To avoid this we only use workers for builds where few files
-   * changed.
-   */
-  @ThreadSafety.ThreadSafe
-  private static class IncrementalHeuristic {
-    private final AtomicBoolean fewFilesChanged = new AtomicBoolean(false);
-    private int limit = 0;
-
-    public boolean shouldUseWorkers() {
-      return limit == 0 || fewFilesChanged.get();
-    }
-
-    IncrementalHeuristic(int limit) {
-      this.limit = limit;
-    }
-
-    @Subscribe
-    public void changedFiles(ChangedFilesMessage msg) {
-      fewFilesChanged.set(msg.getChangedFiles().size() <= limit);
-    }
-  }
 }