Use System#nanoTime() in the server timeout thread because it's monotonous, unlike System#currentTimeMillis().

--
MOS_MIGRATED_REVID=127697254

1 files changed, 14 insertions, 8 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/server/GrpcServerImpl.java b/src/main/java/com/google/devtools/build/lib/server/GrpcServerImpl.java
index 519a439af5..e3e95b4740 100644
--- a/src/main/java/com/google/devtools/build/lib/server/GrpcServerImpl.java
+++ b/src/main/java/com/google/devtools/build/lib/server/GrpcServerImpl.java
@@ -25,6 +25,7 @@ import com.google.devtools.build.lib.server.CommandProtos.PingRequest;
 import com.google.devtools.build.lib.server.CommandProtos.PingResponse;
 import com.google.devtools.build.lib.server.CommandProtos.RunRequest;
 import com.google.devtools.build.lib.server.CommandProtos.RunResponse;
+import com.google.devtools.build.lib.util.BlazeClock;
 import com.google.devtools.build.lib.util.Clock;
 import com.google.devtools.build.lib.util.ExitCode;
 import com.google.devtools.build.lib.util.Preconditions;
@@ -34,10 +35,6 @@ import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.protobuf.ByteString;
 
-import io.grpc.Server;
-import io.grpc.netty.NettyServerBuilder;
-import io.grpc.stub.StreamObserver;
-
 import java.io.IOException;
 import java.io.OutputStream;
 import java.lang.reflect.Field;
@@ -49,10 +46,15 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.UUID;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 
 import javax.annotation.concurrent.GuardedBy;
 
+import io.grpc.Server;
+import io.grpc.netty.NettyServerBuilder;
+import io.grpc.stub.StreamObserver;
+
 /**
  * gRPC server class.
  *
@@ -65,6 +67,8 @@ public class GrpcServerImpl extends RPCServer implements CommandServerGrpc.Comma
   // part correct?
   private static final Charset CHARSET = Charset.forName("ISO-8859-1");
 
+  private static final long NANOSECONDS_IN_MS = TimeUnit.MILLISECONDS.toNanos(1);
+
   private class RunningCommand implements AutoCloseable {
     private final Thread thread;
     private final String id;
@@ -223,15 +227,17 @@ public class GrpcServerImpl extends RPCServer implements CommandServerGrpc.Comma
 
       while (true) {
         if (!wasIdle && idle) {
-          shutdownTime = System.currentTimeMillis() + ((long) maxIdleSeconds) * 1000;
+          shutdownTime = BlazeClock.nanoTime()
+              + ((long) maxIdleSeconds) * 1000L * NANOSECONDS_IN_MS;
         }
 
         try {
           if (idle) {
             Verify.verify(shutdownTime > 0);
-            long waitTime = shutdownTime - System.currentTimeMillis();
+            long waitTime = shutdownTime - BlazeClock.nanoTime();
             if (waitTime > 0) {
-              runningCommands.wait(waitTime);
+              // Round upwards so that we don't busy-wait in the last millisecond
+              runningCommands.wait((waitTime + NANOSECONDS_IN_MS - 1) / NANOSECONDS_IN_MS);
             }
           } else {
             runningCommands.wait();
@@ -242,7 +248,7 @@ public class GrpcServerImpl extends RPCServer implements CommandServerGrpc.Comma
 
         wasIdle = idle;
         idle = runningCommands.isEmpty();
-        if (wasIdle && idle && System.currentTimeMillis() >= shutdownTime) {
+        if (wasIdle && idle && BlazeClock.nanoTime() >= shutdownTime) {
           break;
         }
       }