1 #!/usr/bin/python 2 # 3 # Copyright (c) 2012 The Chromium Authors. All rights reserved. 4 # Use of this source code is governed by a BSD-style license that can be 5 # found in the LICENSE file. 6 7 import logging 8 9 from autotest_lib.client.bin import test, utils 10 from autotest_lib.client.common_lib import error 11 12 class kernel_CpufreqMinMax(test.test): 13 """ 14 Test to ensure cpufreq user min/max limits can be set and reset. 15 16 Test the kernel's ability to change the min and max cpufreq values 17 in both directions. I.e. we must be able to lower the max 18 frequency and then raise it back up again, and raise the minimum 19 frequency and lower it back again. The test on the max is to make 20 sure that thermal throttling will work correctly, and the test on 21 the min is just for symmetry. 22 """ 23 version = 1 24 25 sys_cpufreq_path = '/sys/devices/system/cpu/cpu0/cpufreq/' 26 27 def _test_freq_set(self, freqs, filename): 28 """ 29 Iteratively write frequencies into a file and check the file. 30 31 This is a helper function for testing the min and max 32 given an ordered list, it sets each frequency in the list and 33 then checks to make sure it really got set, and raises an 34 error if it doesn't match. 35 36 @param freqs: a list of frequencies to set 37 @param filename: the filename in the cpufreq directory to use 38 """ 39 for freq in freqs: 40 logging.info('setting %s to %d' % (filename, freq)) 41 f = open(self.sys_cpufreq_path + filename, 'w') 42 f.write(str(freq)) 43 f.close() 44 45 f = open(self.sys_cpufreq_path + filename, 'r') 46 cur_freq = int(f.readline()) 47 f.close() 48 49 if (cur_freq != freq): 50 logging.info('%s was set to %d instead of %d' % 51 (filename, cur_freq, freq)) 52 raise error.TestFail('unable to set %s to %d' % 53 (filename, freq)) 54 55 56 def run_once(self): 57 available_freqs = [] 58 # When the Intel P-state driver is used, the driver implements an 59 # internal governer which selects the currect P-state automatically. 60 # Any value between cpuinfo_min_freq and cpuinfo_max_freq is allowed 61 # for scaling_max_freq and scaling_min_freq. Setting them is 62 # equivalent to setting max_perf_pct and min_perf_pct under 63 # /sys/devices/system/cpu/intel_pstate/. 64 f = open(self.sys_cpufreq_path + 'scaling_driver', 'r') 65 if ('intel_pstate\n' == f.read()): 66 fmin = open(self.sys_cpufreq_path + 'cpuinfo_min_freq', 'r') 67 fmax = open(self.sys_cpufreq_path + 'cpuinfo_max_freq', 'r') 68 available_freqs = map(int, [fmin.read(), fmax.read()]) 69 fmin.close() 70 fmax.close() 71 72 # generate a list of frequencies between min and max 73 step = (available_freqs[1] - available_freqs[0]) / 4 74 if step: 75 available_freqs = range(available_freqs[0], 76 available_freqs[1] + 1, step) 77 f.close() 78 79 if not available_freqs: 80 f = open(self.sys_cpufreq_path + 'scaling_available_frequencies', 'r') 81 available_freqs = sorted(map(int, f.readline().split())) 82 f.close() 83 84 # exit if there are not at least two frequencies 85 if (len(available_freqs) < 2): 86 return 87 88 # get current maximum scaling frequency 89 f = open(self.sys_cpufreq_path + 'scaling_max_freq', 'r') 90 max_freq = int(f.readline()) 91 f.close() 92 93 if max_freq < available_freqs[-1]: 94 logging.info( 95 'Current maximum frequency %d is lower than available maximum %d', 96 max_freq, available_freqs[-1]) 97 # Board is probably thermally throttled 98 if not utils.wait_for_cool_machine(): 99 raise error.TestFail('Could not get cold machine.') 100 101 # set max to 2nd to highest frequency, then the highest 102 self._test_freq_set(available_freqs[-2:], 'scaling_max_freq') 103 104 # set to min 2nd to lowest frequency, then the lowest 105 self._test_freq_set(reversed(available_freqs[:2]), 106 'scaling_min_freq') 107
