[test] Dump processes when test driver hangs

This prints the current v8-specific processes on linux whenever the
test driver emits a heart beat (i.e. no output for 30 seconds).

This is to investigate the cause of currently hanging tests on linux.

Bug: v8:9145
Change-Id: I857bb6d1c5f0b0917c64cdc0aa6076c6633f9dd6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1578438
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60941}

tools/testrunner/testproc/progress.py

@@ -7,12 +7,19 @@ from __future__ import print_function
 
 import json
 import os
+import platform
+import subprocess
 import sys
 import time
 
 from . import base
 
 
+# Base dir of the build products for Release and Debug.
+OUT_DIR = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..', '..', '..', 'out'))
+
+
 def print_failure_header(test):
   if test.output_proc.negative:
     negative_marker = '[negative] '
@@ -120,11 +127,26 @@ class VerboseProgressIndicator(SimpleProgressIndicator):
     self._print('Done running %s %s: %s' % (
       test, test.variant or 'default', outcome))
 
+  # TODO(machenbach): Remove this platform specific hack and implement a proper
+  # feedback channel from the workers, providing which tests are currently run.
+  def _print_processes_linux(self):
+    if platform.system() == 'Linux':
+      try:
+        cmd = 'ps -aux | grep "%s"' % OUT_DIR
+        output = subprocess.check_output(cmd, shell=True)
+        self._print('List of processes:')
+        for line in (output or '').splitlines():
+          # Show only command with process info cut off.
+          self._print(line[line.index(OUT_DIR):])
+      except:
+        pass
+
   def _on_heartbeat(self):
     if time.time() - self._last_printed_time > 30:
       # Print something every 30 seconds to not get killed by an output
       # timeout.
       self._print('Still working...')
+      self._print_processes_linux()
 
 
 class DotsProgressIndicator(SimpleProgressIndicator):