1# Copyright 2019 The TensorFlow Authors. All Rights Reserved. 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14# ============================================================================== 15"""Contains function to log if devices are compatible with mixed precision.""" 16 17import itertools 18 19from tensorflow.python.framework import config 20from tensorflow.python.platform import tf_logging 21 22 23_COMPAT_CHECK_PREFIX = 'Mixed precision compatibility check (mixed_float16): ' 24_COMPAT_CHECK_OK_PREFIX = _COMPAT_CHECK_PREFIX + 'OK' 25_COMPAT_CHECK_WARNING_PREFIX = _COMPAT_CHECK_PREFIX + 'WARNING' 26_COMPAT_CHECK_WARNING_SUFFIX = ( 27 'If you will use compatible GPU(s) not attached to this host, e.g. by ' 28 'running a multi-worker model, you can ignore this warning. This message ' 29 'will only be logged once') 30 31 32def _dedup_strings(device_strs): 33 """Groups together consecutive identical strings. 34 35 For example, given: 36 ['GPU 1', 'GPU 2', 'GPU 2', 'GPU 3', 'GPU 3', 'GPU 3'] 37 This function returns: 38 ['GPU 1', 'GPU 2 (x2)', 'GPU 3 (x3)'] 39 40 Args: 41 device_strs: A list of strings, each representing a device. 42 43 Returns: 44 A copy of the input, but identical consecutive strings are merged into a 45 single string. 46 """ 47 new_device_strs = [] 48 for device_str, vals in itertools.groupby(device_strs): 49 num = len(list(vals)) 50 if num == 1: 51 new_device_strs.append(device_str) 52 else: 53 new_device_strs.append('%s (x%d)' % (device_str, num)) 54 return new_device_strs 55 56 57def _log_device_compatibility_check(policy_name, gpu_details_list): 58 """Logs a compatibility check if the devices support the policy. 59 60 Currently only logs for the policy mixed_float16. 61 62 Args: 63 policy_name: The name of the dtype policy. 64 gpu_details_list: A list of dicts, one dict per GPU. Each dict 65 is the device details for a GPU, as returned by 66 `tf.config.experimental.get_device_details()`. 67 """ 68 if policy_name != 'mixed_float16': 69 # TODO(b/145686977): Log if the policy is 'mixed_bfloat16'. This requires 70 # checking if a TPU is available. 71 return 72 supported_device_strs = [] 73 unsupported_device_strs = [] 74 for details in gpu_details_list: 75 name = details.get('device_name', 'Unknown GPU') 76 cc = details.get('compute_capability') 77 if cc: 78 device_str = '%s, compute capability %s.%s' % (name, cc[0], cc[1]) 79 if cc >= (7, 0): 80 supported_device_strs.append(device_str) 81 else: 82 unsupported_device_strs.append(device_str) 83 else: 84 unsupported_device_strs.append( 85 name + ', no compute capability (probably not an Nvidia GPU)') 86 87 if unsupported_device_strs: 88 warning_str = _COMPAT_CHECK_WARNING_PREFIX + '\n' 89 if supported_device_strs: 90 warning_str += ('Some of your GPUs may run slowly with dtype policy ' 91 'mixed_float16 because they do not all have compute ' 92 'capability of at least 7.0. Your GPUs:\n') 93 elif len(unsupported_device_strs) == 1: 94 warning_str += ('Your GPU may run slowly with dtype policy mixed_float16 ' 95 'because it does not have compute capability of at least ' 96 '7.0. Your GPU:\n') 97 else: 98 warning_str += ('Your GPUs may run slowly with dtype policy ' 99 'mixed_float16 because they do not have compute ' 100 'capability of at least 7.0. Your GPUs:\n') 101 for device_str in _dedup_strings(supported_device_strs + 102 unsupported_device_strs): 103 warning_str += ' ' + device_str + '\n' 104 warning_str += ('See https://developer.nvidia.com/cuda-gpus for a list of ' 105 'GPUs and their compute capabilities.\n') 106 warning_str += _COMPAT_CHECK_WARNING_SUFFIX 107 tf_logging.warning(warning_str) 108 elif not supported_device_strs: 109 tf_logging.warning( 110 '%s\n' 111 'The dtype policy mixed_float16 may run slowly because ' 112 'this machine does not have a GPU. Only Nvidia GPUs with ' 113 'compute capability of at least 7.0 run quickly with ' 114 'mixed_float16.\n%s' % (_COMPAT_CHECK_WARNING_PREFIX, 115 _COMPAT_CHECK_WARNING_SUFFIX)) 116 elif len(supported_device_strs) == 1: 117 tf_logging.info('%s\n' 118 'Your GPU will likely run quickly with dtype policy ' 119 'mixed_float16 as it has compute capability of at least ' 120 '7.0. Your GPU: %s' % (_COMPAT_CHECK_OK_PREFIX, 121 supported_device_strs[0])) 122 else: 123 tf_logging.info('%s\n' 124 'Your GPUs will likely run quickly with dtype policy ' 125 'mixed_float16 as they all have compute capability of at ' 126 'least 7.0' % _COMPAT_CHECK_OK_PREFIX) 127 128 129_logged_compatibility_check = False 130 131 132def log_device_compatibility_check(policy_name): 133 """Logs a compatibility check if the devices support the policy. 134 135 Currently only logs for the policy mixed_float16. A log is shown only the 136 first time this function is called. 137 138 Args: 139 policy_name: The name of the dtype policy. 140 """ 141 global _logged_compatibility_check 142 if _logged_compatibility_check: 143 return 144 _logged_compatibility_check = True 145 gpus = config.list_physical_devices('GPU') 146 gpu_details_list = [config.get_device_details(g) for g in gpus] 147 _log_device_compatibility_check(policy_name, gpu_details_list) 148