set default log dir for TensorboardLoggerHook

examples/config_cifar10.py

@@ -14,7 +14,7 @@ lr_config = dict(policy='step', step=2)
 # runtime settings
 work_dir = './demo'
 gpus = range(2)
-dist_params = dict(backend='gloo')  # gloo is much slower than nccl
+dist_params = dict(backend='nccl')
 data_workers = 2  # data workers per gpu
 checkpoint_config = dict(interval=1)  # save checkpoint at every epoch
 workflow = [('train', 1), ('val', 1)]
@@ -28,5 +28,5 @@ log_config = dict(
     interval=50,  # log at every 50 iterations
     hooks=[
         dict(type='TextLoggerHook'),
-        # dict(type='TensorboardLoggerHook', log_dir=work_dir + '/log'),
+        # dict(type='TensorboardLoggerHook'),
     ])

mmcv/runner/hooks/logger/tensorboard.py

+import os.path as osp
+
 from .base import LoggerHook
 from ...utils import master_only
 
 
 class TensorboardLoggerHook(LoggerHook):
 
-    def __init__(self, log_dir, interval=10, ignore_last=True,
+    def __init__(self,
+                 log_dir=None,
+                 interval=10,
+                 ignore_last=True,
                  reset_flag=True):
         super(TensorboardLoggerHook, self).__init__(interval, ignore_last,
                                                     reset_flag)
@@ -18,6 +23,8 @@ class TensorboardLoggerHook(LoggerHook):
             raise ImportError('Please install tensorflow and tensorboardX '
                               'to use TensorboardLoggerHook.')
         else:
+            if self.log_dir is None:
+                self.log_dir = osp.join(runner.work_dir, 'tf_logs')
             self.writer = SummaryWriter(self.log_dir)
 
     @master_only