Make cpu scaling more robust

Some bots, especially the Nexus 7s, seemed to occasionally
fail when setting the CPU frequency.  I was unable to
repro this behavior, so this is a shotgun approach.

We add a 5 second delay between setting and checking,
checking frequency using scaling_cur_freq instead of
scaling_setspeed, set the min_freq as well as max_freq,
and retry up to 3 times if setting cpu frequency fails.

NOTRY=true
Bug: skia:
Change-Id: Id4d85d8d509c9dba8e3a0e06b5992f5adadf36d2
Reviewed-on: https://skia-review.googlesource.com/78140
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Eric Boren <borenet@google.com>

1 files changed, 169 insertions, 3 deletions

diff --git a/infra/bots/recipes/perf.expected/cpu_scale_failed.json b/infra/bots/recipes/perf.expected/cpu_scale_failed.json
index 1c70a873ab..84161e13ac 100644
--- a/infra/bots/recipes/perf.expected/cpu_scale_failed.json
+++ b/infra/bots/recipes/perf.expected/cpu_scale_failed.json
@@ -540,7 +540,7 @@
     "cmd": [
       "python",
       "-u",
-      "\nimport os\nimport subprocess\nimport sys\nADB = sys.argv[1]\nmodel = sys.argv[2]\ntarget_percent = float(sys.argv[3])\nlog = subprocess.check_output([ADB, 'root'])\n# check for message like 'adbd cannot run as root in production builds'\nif 'cannot' in log:\n  raise Exception('adb root failed')\n\nif model == 'Nexus10':\n  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]\nelif model == 'Nexus7':\n  # Nexus7 claims to support 1300000, but only really allows 1200000\n  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,\n                     860000, 1000000, 1100000, 1200000]\nelse:\n  # Most devices give a list of their available frequencies.\n  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '\n      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])\n\n  # Check for message like '/system/bin/sh: file not found'\n  if available_freqs and '/system/bin/sh' not in available_freqs:\n    available_freqs = sorted(\n        int(i) for i in available_freqs.strip().split())\n  else:\n    raise Exception('Could not get list of available frequencies: %s' %\n                    available_freqs)\n\nmaxfreq = available_freqs[-1]\ntarget = int(round(maxfreq * target_percent))\nfreq = maxfreq\nfor f in reversed(available_freqs):\n  if f <= target:\n    freq = f\n    break\n\nprint 'Setting frequency to %d' % freq\n\nsubprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])\n# If scaling_max_freq is lower than our attempted setting, it won't take.\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])\nactual_freq = subprocess.check_output([ADB, 'shell', 'cat '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed']).strip()\nif actual_freq != str(freq):\n  raise Exception('(actual, expected) (%s, %d)'\n                  % (actual_freq, freq))\n",
+      "\nimport os\nimport subprocess\nimport sys\nimport time\nADB = sys.argv[1]\nmodel = sys.argv[2]\ntarget_percent = float(sys.argv[3])\nlog = subprocess.check_output([ADB, 'root'])\n# check for message like 'adbd cannot run as root in production builds'\nif 'cannot' in log:\n  raise Exception('adb root failed')\n\nif model == 'Nexus10':\n  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]\nelif model == 'Nexus7':\n  # Nexus7 claims to support 1300000, but only really allows 1200000\n  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,\n                     860000, 1000000, 1100000, 1200000]\nelse:\n  # Most devices give a list of their available frequencies.\n  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '\n      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])\n\n  # Check for message like '/system/bin/sh: file not found'\n  if available_freqs and '/system/bin/sh' not in available_freqs:\n    available_freqs = sorted(\n        int(i) for i in available_freqs.strip().split())\n  else:\n    raise Exception('Could not get list of available frequencies: %s' %\n                    available_freqs)\n\nmaxfreq = available_freqs[-1]\ntarget = int(round(maxfreq * target_percent))\nfreq = maxfreq\nfor f in reversed(available_freqs):\n  if f <= target:\n    freq = f\n    break\n\nprint 'Setting frequency to %d' % freq\n\nsubprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])\n# If scaling_max_freq is lower than our attempted setting, it won't take.\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])\ntime.sleep(5)\nactual_freq = subprocess.check_output([ADB, 'shell', 'cat '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()\nif actual_freq != str(freq):\n  raise Exception('(actual, expected) (%s, %d)'\n                  % (actual_freq, freq))\n",
       "adb.1.0.35",
       "NexusPlayer",
       "0.6"
@@ -560,6 +560,7 @@
       "@@@STEP_LOG_LINE@python.inline@import os@@@",
       "@@@STEP_LOG_LINE@python.inline@import subprocess@@@",
       "@@@STEP_LOG_LINE@python.inline@import sys@@@",
+      "@@@STEP_LOG_LINE@python.inline@import time@@@",
       "@@@STEP_LOG_LINE@python.inline@ADB = sys.argv[1]@@@",
       "@@@STEP_LOG_LINE@python.inline@model = sys.argv[2]@@@",
       "@@@STEP_LOG_LINE@python.inline@target_percent = float(sys.argv[3])@@@",
@@ -603,9 +604,174 @@
       "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
       "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])@@@",
       "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@time.sleep(5)@@@",
+      "@@@STEP_LOG_LINE@python.inline@actual_freq = subprocess.check_output([ADB, 'shell', 'cat '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()@@@",
+      "@@@STEP_LOG_LINE@python.inline@if actual_freq != str(freq):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  raise Exception('(actual, expected) (%s, %d)'@@@",
+      "@@@STEP_LOG_LINE@python.inline@                  % (actual_freq, freq))@@@",
+      "@@@STEP_LOG_END@python.inline@@@",
+      "@@@STEP_EXCEPTION@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "\nimport os\nimport subprocess\nimport sys\nimport time\nADB = sys.argv[1]\nmodel = sys.argv[2]\ntarget_percent = float(sys.argv[3])\nlog = subprocess.check_output([ADB, 'root'])\n# check for message like 'adbd cannot run as root in production builds'\nif 'cannot' in log:\n  raise Exception('adb root failed')\n\nif model == 'Nexus10':\n  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]\nelif model == 'Nexus7':\n  # Nexus7 claims to support 1300000, but only really allows 1200000\n  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,\n                     860000, 1000000, 1100000, 1200000]\nelse:\n  # Most devices give a list of their available frequencies.\n  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '\n      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])\n\n  # Check for message like '/system/bin/sh: file not found'\n  if available_freqs and '/system/bin/sh' not in available_freqs:\n    available_freqs = sorted(\n        int(i) for i in available_freqs.strip().split())\n  else:\n    raise Exception('Could not get list of available frequencies: %s' %\n                    available_freqs)\n\nmaxfreq = available_freqs[-1]\ntarget = int(round(maxfreq * target_percent))\nfreq = maxfreq\nfor f in reversed(available_freqs):\n  if f <= target:\n    freq = f\n    break\n\nprint 'Setting frequency to %d' % freq\n\nsubprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])\n# If scaling_max_freq is lower than our attempted setting, it won't take.\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])\ntime.sleep(5)\nactual_freq = subprocess.check_output([ADB, 'shell', 'cat '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()\nif actual_freq != str(freq):\n  raise Exception('(actual, expected) (%s, %d)'\n                  % (actual_freq, freq))\n",
+      "adb.1.0.35",
+      "NexusPlayer",
+      "0.6"
+    ],
+    "env": {
+      "BUILDTYPE": "Debug",
+      "CHROME_HEADLESS": "1",
+      "PATH": "<PATH>:RECIPE_PACKAGE_REPO[depot_tools]",
+      "SKIA_OUT": "[START_DIR]/out"
+    },
+    "infra_step": true,
+    "name": "Scale CPU to 0.600000 (attempt 2)",
+    "timeout": 30,
+    "~followup_annotations": [
+      "step returned non-zero exit code: 1",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import os@@@",
+      "@@@STEP_LOG_LINE@python.inline@import subprocess@@@",
+      "@@@STEP_LOG_LINE@python.inline@import sys@@@",
+      "@@@STEP_LOG_LINE@python.inline@import time@@@",
+      "@@@STEP_LOG_LINE@python.inline@ADB = sys.argv[1]@@@",
+      "@@@STEP_LOG_LINE@python.inline@model = sys.argv[2]@@@",
+      "@@@STEP_LOG_LINE@python.inline@target_percent = float(sys.argv[3])@@@",
+      "@@@STEP_LOG_LINE@python.inline@log = subprocess.check_output([ADB, 'root'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@# check for message like 'adbd cannot run as root in production builds'@@@",
+      "@@@STEP_LOG_LINE@python.inline@if 'cannot' in log:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  raise Exception('adb root failed')@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@if model == 'Nexus10':@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]@@@",
+      "@@@STEP_LOG_LINE@python.inline@elif model == 'Nexus7':@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Nexus7 claims to support 1300000, but only really allows 1200000@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,@@@",
+      "@@@STEP_LOG_LINE@python.inline@                     860000, 1000000, 1100000, 1200000]@@@",
+      "@@@STEP_LOG_LINE@python.inline@else:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Most devices give a list of their available frequencies.@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '@@@",
+      "@@@STEP_LOG_LINE@python.inline@      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Check for message like '/system/bin/sh: file not found'@@@",
+      "@@@STEP_LOG_LINE@python.inline@  if available_freqs and '/system/bin/sh' not in available_freqs:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    available_freqs = sorted(@@@",
+      "@@@STEP_LOG_LINE@python.inline@        int(i) for i in available_freqs.strip().split())@@@",
+      "@@@STEP_LOG_LINE@python.inline@  else:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    raise Exception('Could not get list of available frequencies: %s' %@@@",
+      "@@@STEP_LOG_LINE@python.inline@                    available_freqs)@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@maxfreq = available_freqs[-1]@@@",
+      "@@@STEP_LOG_LINE@python.inline@target = int(round(maxfreq * target_percent))@@@",
+      "@@@STEP_LOG_LINE@python.inline@freq = maxfreq@@@",
+      "@@@STEP_LOG_LINE@python.inline@for f in reversed(available_freqs):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  if f <= target:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    freq = f@@@",
+      "@@@STEP_LOG_LINE@python.inline@    break@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@print 'Setting frequency to %d' % freq@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@# If scaling_max_freq is lower than our attempted setting, it won't take.@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@time.sleep(5)@@@",
+      "@@@STEP_LOG_LINE@python.inline@actual_freq = subprocess.check_output([ADB, 'shell', 'cat '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()@@@",
+      "@@@STEP_LOG_LINE@python.inline@if actual_freq != str(freq):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  raise Exception('(actual, expected) (%s, %d)'@@@",
+      "@@@STEP_LOG_LINE@python.inline@                  % (actual_freq, freq))@@@",
+      "@@@STEP_LOG_END@python.inline@@@",
+      "@@@STEP_EXCEPTION@@@"
+    ]
+  },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "\nimport os\nimport subprocess\nimport sys\nimport time\nADB = sys.argv[1]\nmodel = sys.argv[2]\ntarget_percent = float(sys.argv[3])\nlog = subprocess.check_output([ADB, 'root'])\n# check for message like 'adbd cannot run as root in production builds'\nif 'cannot' in log:\n  raise Exception('adb root failed')\n\nif model == 'Nexus10':\n  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]\nelif model == 'Nexus7':\n  # Nexus7 claims to support 1300000, but only really allows 1200000\n  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,\n                     860000, 1000000, 1100000, 1200000]\nelse:\n  # Most devices give a list of their available frequencies.\n  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '\n      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])\n\n  # Check for message like '/system/bin/sh: file not found'\n  if available_freqs and '/system/bin/sh' not in available_freqs:\n    available_freqs = sorted(\n        int(i) for i in available_freqs.strip().split())\n  else:\n    raise Exception('Could not get list of available frequencies: %s' %\n                    available_freqs)\n\nmaxfreq = available_freqs[-1]\ntarget = int(round(maxfreq * target_percent))\nfreq = maxfreq\nfor f in reversed(available_freqs):\n  if f <= target:\n    freq = f\n    break\n\nprint 'Setting frequency to %d' % freq\n\nsubprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])\n# If scaling_max_freq is lower than our attempted setting, it won't take.\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])\nsubprocess.check_output([ADB, 'shell', 'echo %d > '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])\ntime.sleep(5)\nactual_freq = subprocess.check_output([ADB, 'shell', 'cat '\n    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()\nif actual_freq != str(freq):\n  raise Exception('(actual, expected) (%s, %d)'\n                  % (actual_freq, freq))\n",
+      "adb.1.0.35",
+      "NexusPlayer",
+      "0.6"
+    ],
+    "env": {
+      "BUILDTYPE": "Debug",
+      "CHROME_HEADLESS": "1",
+      "PATH": "<PATH>:RECIPE_PACKAGE_REPO[depot_tools]",
+      "SKIA_OUT": "[START_DIR]/out"
+    },
+    "infra_step": true,
+    "name": "Scale CPU to 0.600000 (attempt 3)",
+    "timeout": 30,
+    "~followup_annotations": [
+      "step returned non-zero exit code: 1",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@import os@@@",
+      "@@@STEP_LOG_LINE@python.inline@import subprocess@@@",
+      "@@@STEP_LOG_LINE@python.inline@import sys@@@",
+      "@@@STEP_LOG_LINE@python.inline@import time@@@",
+      "@@@STEP_LOG_LINE@python.inline@ADB = sys.argv[1]@@@",
+      "@@@STEP_LOG_LINE@python.inline@model = sys.argv[2]@@@",
+      "@@@STEP_LOG_LINE@python.inline@target_percent = float(sys.argv[3])@@@",
+      "@@@STEP_LOG_LINE@python.inline@log = subprocess.check_output([ADB, 'root'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@# check for message like 'adbd cannot run as root in production builds'@@@",
+      "@@@STEP_LOG_LINE@python.inline@if 'cannot' in log:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  raise Exception('adb root failed')@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@if model == 'Nexus10':@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = [200000, 300000, 400000, 500000, 600000, 700000, 800000]@@@",
+      "@@@STEP_LOG_LINE@python.inline@elif model == 'Nexus7':@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Nexus7 claims to support 1300000, but only really allows 1200000@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = [51000, 102000, 204000, 340000, 475000, 640000, 760000,@@@",
+      "@@@STEP_LOG_LINE@python.inline@                     860000, 1000000, 1100000, 1200000]@@@",
+      "@@@STEP_LOG_LINE@python.inline@else:@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Most devices give a list of their available frequencies.@@@",
+      "@@@STEP_LOG_LINE@python.inline@  available_freqs = subprocess.check_output([ADB, 'shell', 'cat '@@@",
+      "@@@STEP_LOG_LINE@python.inline@      '/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@  # Check for message like '/system/bin/sh: file not found'@@@",
+      "@@@STEP_LOG_LINE@python.inline@  if available_freqs and '/system/bin/sh' not in available_freqs:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    available_freqs = sorted(@@@",
+      "@@@STEP_LOG_LINE@python.inline@        int(i) for i in available_freqs.strip().split())@@@",
+      "@@@STEP_LOG_LINE@python.inline@  else:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    raise Exception('Could not get list of available frequencies: %s' %@@@",
+      "@@@STEP_LOG_LINE@python.inline@                    available_freqs)@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@maxfreq = available_freqs[-1]@@@",
+      "@@@STEP_LOG_LINE@python.inline@target = int(round(maxfreq * target_percent))@@@",
+      "@@@STEP_LOG_LINE@python.inline@freq = maxfreq@@@",
+      "@@@STEP_LOG_LINE@python.inline@for f in reversed(available_freqs):@@@",
+      "@@@STEP_LOG_LINE@python.inline@  if f <= target:@@@",
+      "@@@STEP_LOG_LINE@python.inline@    freq = f@@@",
+      "@@@STEP_LOG_LINE@python.inline@    break@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@print 'Setting frequency to %d' % freq@@@",
+      "@@@STEP_LOG_LINE@python.inline@@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo \"userspace\" > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor'])@@@",
+      "@@@STEP_LOG_LINE@python.inline@# If scaling_max_freq is lower than our attempted setting, it won't take.@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@subprocess.check_output([ADB, 'shell', 'echo %d > '@@@",
       "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed' % freq])@@@",
+      "@@@STEP_LOG_LINE@python.inline@time.sleep(5)@@@",
       "@@@STEP_LOG_LINE@python.inline@actual_freq = subprocess.check_output([ADB, 'shell', 'cat '@@@",
-      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed']).strip()@@@",
+      "@@@STEP_LOG_LINE@python.inline@    '/sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq']).strip()@@@",
       "@@@STEP_LOG_LINE@python.inline@if actual_freq != str(freq):@@@",
       "@@@STEP_LOG_LINE@python.inline@  raise Exception('(actual, expected) (%s, %d)'@@@",
       "@@@STEP_LOG_LINE@python.inline@                  % (actual_freq, freq))@@@",
@@ -682,7 +848,7 @@
   },
   {
     "name": "$result",
-    "reason": "Failed build steps: Scale CPU to 0.600000, Scale CPU to 0.600000",
+    "reason": "Failed build steps: Scale CPU to 0.600000, Scale CPU to 0.600000 (attempt 2), Scale CPU to 0.600000 (attempt 3), Scale CPU to 0.600000 (attempt 3)",
     "recipe_result": null,
     "status_code": 1
   }