Disable smoothness.tough_animation_cases on low-end win bots

tools/perf/benchmarks/smoothness.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+import multiprocessing
 
 from core import perf_benchmark
 
 from benchmarks import silk_flags
 from measurements import smoothness
 import page_sets
 import page_sets.key_silk_cases
 from telemetry import benchmark
 
 
@@ skipping 118 matching lines @@
 @benchmark.Disabled('android-reference')  # crbug.com/588786
 @benchmark.Disabled('mac')  # crbug.com/563615
 class SmoothnessToughAnimationCases(_Smoothness):
   test = smoothness.SmoothnessWithRestart
   page_set = page_sets.ToughAnimationCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.tough_animation_cases'
 
+  @classmethod
+  def ShouldDisable(cls, possible_browser):  # http://crbug.com/595737
+    # This test is flaky on low-end windows machine.
+    return (possible_browser.platform.GetOSName() == 'win' and
+            multiprocessing.cpu_count() <= 2)
+
 
 @benchmark.Enabled('android')
 class SmoothnessKeySilkCases(_Smoothness):
   """Measures rendering statistics for the key silk cases without GPU
   rasterization.
   """
   page_set = page_sets.KeySilkCasesPageSet
 
   @classmethod
   def Name(cls):
@@ skipping 367 matching lines @@
   """Measures rendering statistics while scrolling advertisements."""
   page_set = page_sets.SyntheticToughWebglAdCasesPageSet
 
   @classmethod
   def Name(cls):
     return 'smoothness.tough_webgl_ad_cases'
 
   @classmethod
   def ShouldDisable(cls, possible_browser):
     return cls.IsSvelte(possible_browser)  # http://crbug.com/574485