diff --git a/src/daemon/PhutilDaemon.php b/src/daemon/PhutilDaemon.php
--- a/src/daemon/PhutilDaemon.php
+++ b/src/daemon/PhutilDaemon.php
@@ -47,6 +47,7 @@
   const MESSAGETYPE_BUSY = 'busy';
   const MESSAGETYPE_IDLE = 'idle';
   const MESSAGETYPE_DOWN = 'down';
+  const MESSAGETYPE_HIBERNATE = 'hibernate';
 
   const WORKSTATE_BUSY = 'busy';
   const WORKSTATE_IDLE = 'idle';
@@ -125,6 +126,35 @@
     return $this->inGracefulShutdown;
   }
 
+  final protected function shouldHibernate($duration) {
+    // Don't hibernate if we don't have very long to sleep.
+    if ($duration < 5) {
+      return false;
+    }
+
+    // Never hibernate if we're part of a pool and could scale down instead.
+    // We only hibernate the last process to drop the pool size to zero.
+    if ($this->getScaledownDuration()) {
+      return false;
+    }
+
+    // Don't hibernate for too long.
+    $duration = max($duration, phutil_units('3 minutes in seconds'));
+
+    $this->emitOverseerMessage(
+      self::MESSAGETYPE_HIBERNATE,
+      array(
+        'duration' => $duration,
+      ));
+
+    $this->log(
+      pht(
+        'Preparing to hibernate for %s second(s).',
+        new PhutilNumber($duration)));
+
+    return true;
+  }
+
   final protected function sleep($duration) {
     $this->notifyReceived = false;
     $this->willSleep($duration);
diff --git a/src/daemon/PhutilDaemonHandle.php b/src/daemon/PhutilDaemonHandle.php
--- a/src/daemon/PhutilDaemonHandle.php
+++ b/src/daemon/PhutilDaemonHandle.php
@@ -192,8 +192,18 @@
   }
 
   private function scheduleRestart() {
-    $this->logMessage('WAIT', pht('Waiting to restart process.'));
-    $this->restartAt = time() + self::getWaitBeforeRestart();
+    // Wait a minimum of a few sceconds before restarting, but we may wait
+    // longer if the daemon has initiated hibernation.
+    $default_restart = time() + self::getWaitBeforeRestart();
+    if ($default_restart >= $this->restartAt) {
+      $this->restartAt = $default_restart;
+    }
+
+    $this->logMessage(
+      'WAIT',
+      pht(
+        'Waiting %s second(s) to restart process.',
+        new PhutilNumber($this->restartAt - time())));
   }
 
   /**
@@ -352,6 +362,16 @@
           $this->shouldRestart = false;
           $this->shouldShutdown = true;
           break;
+        case PhutilDaemon::MESSAGETYPE_HIBERNATE:
+          $config = idx($structure, 1);
+          $duration = (int)idx($config, 'duration', 0);
+          $this->restartAt = time() + $duration;
+          $this->logMessage(
+            'ZZZZ',
+            pht(
+              'Process is preparing to hibernate for %s second(s).',
+              new PhutilNumber($duration)));
+          break;
         default:
           // If we can't parse this or it isn't a message we understand, just
           // emit the raw message.