GPU Util Tracker use CUDA_VISIBLE_DEVICES

tensorpack/callbacks/stats.py

@@ -35,16 +35,22 @@ class SendStat(Callback):
 class GPUUtilizationTracker(Callback):
     """ Summarize the average GPU utilization within an epoch"""
 
-    def __init__(self, devices):
+    def __init__(self, devices=None):
         """
         Args:
-            devices (list[int]): physical GPU ids
+            devices (list[int]): physical GPU ids. If None, will use CUDA_VISIBLE_DEVICES
         """
+        if devices is None:
+            env = os.environ.get('CUDA_VISIBLE_DEVICES')
+            assert env is not None, "[GPUUtilizationTracker] Both devices and CUDA_VISIBLE_DEVICES are None!"
+            self._devices = env.split(',')
+        else:
             self._devices = list(map(str, devices))
+        assert len(self._devices), "[GPUUtilizationTracker] No GPU device given!"
 
         self._command = "nvidia-smi --query-gpu=utilization.gpu --format=csv,noheader,nounits -i " + \
             ','.join(self._devices)
-        output, ret = subproc_call(self._command)
+        _, ret = subproc_call(self._command)
         assert ret == 0, "Cannot fetch GPU utilization!"
 
     def _before_train(self):