skpbench: use 3 cores instead of 4 on Pixel C

tools/skpbench/_hardware_pixel_c.py

Index: tools/skpbench/_hardware_pixel_c.py
diff --git a/tools/skpbench/_hardware_pixel_c.py b/tools/skpbench/_hardware_pixel_c.py
index 842ee0c50235b1fbef109448d048cfbb80f51d3d..47f3ec4b0b355078727a9d7f6771a9e0124a1f55 100644
--- a/tools/skpbench/_hardware_pixel_c.py
+++ b/tools/skpbench/_hardware_pixel_c.py
@@ -28,12 +28,19 @@ class HardwarePixelC(HardwareAndroid):
       return
 
     self._adb.shell('\n'.join([
-      # lock cpu clocks.
+      # turn on and lock the first 3 cores.
       '''
-      for N in $(seq 0 3); do
+      for N in 0 1 2; do
+        echo 1 > /sys/devices/system/cpu/cpu$N/online
         echo userspace > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_governor
+        echo %i > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_max_freq
+        echo %i > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_min_freq
         echo %i > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_setspeed
-      done''' % CPU_CLOCK_RATE,
+      done''' % tuple(CPU_CLOCK_RATE for _ in range(3)),
+
+      # turn off the fourth core.
+      '''
+      echo 0 > /sys/devices/system/cpu/cpu3/online''',
 
       # lock gpu/emc clocks.
       '''
@@ -50,9 +57,15 @@ class HardwarePixelC(HardwareAndroid):
       echo auto > /sys/devices/57000000.gpu/pstate
       chown system:system /sys/devices/57000000.gpu/pstate''',
 
-      # unlock cpu clocks.
+      # turn the fourth core back on.
+      '''
+      echo 1 > /sys/devices/system/cpu/cpu3/online''',
+
+      # unlock the first 3 cores.
       '''
-      for N in $(seq 0 3); do
+      for N in 2 1 0; do
+        echo 1912500 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_max_freq
+        echo 51000 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_min_freq
         echo 0 > /sys/devices/system/cpu/cpu$N/cpufreq/scaling_setspeed
         echo interactive >/sys/devices/system/cpu/cpu$N/cpufreq/scaling_governor
       done''']))
@@ -66,18 +79,20 @@ class HardwarePixelC(HardwareAndroid):
     # only issue one shell command in an attempt to minimize interference.
     result = self._adb.check('''\
       cat /sys/class/power_supply/bq27742-0/capacity \
+          /sys/devices/system/cpu/online \
           /sys/class/thermal/thermal_zone7/temp \
           /sys/class/thermal/thermal_zone0/temp \
           /sys/class/thermal/thermal_zone1/temp \
           /sys/class/thermal/thermal_zone7/cdev1/cur_state \
           /sys/class/thermal/thermal_zone7/cdev0/cur_state
-      for N in $(seq 0 3); do
+      for N in 0 1 2; do
         cat /sys/devices/system/cpu/cpu$N/cpufreq/scaling_cur_freq
       done
       cat /sys/devices/57000000.gpu/pstate | grep \*$''')
 
     expectations = \
       [Expectation(int, min_value=30, name='battery', sleeptime=30*60),
+       Expectation(str, exact_value='0-2', name='online cpus'),
        Expectation(int, max_value=40000, name='skin temperature'),
        Expectation(int, max_value=86000, name='cpu temperature'),
        Expectation(int, max_value=87000, name='gpu temperature'),
@@ -85,7 +100,7 @@ class HardwarePixelC(HardwareAndroid):
        Expectation(int, exact_value=0, name='gpu throttle')] + \
       [Expectation(int, exact_value=CPU_CLOCK_RATE,
                    name='cpu_%i clock rate' % i, sleeptime=30)
-       for i in range(4)] + \
+       for i in (0, 1, 2)] + \
       [Expectation(str, exact_value=GPU_EMC_PROFILE, name='gpu/emc profile')]
 
     Expectation.check_all(expectations, result.splitlines())