I used the MLlib of spark to run some experiments, such as the lasso, and linear regression etc. I just use the given model in MLlib: LassoWithSGD, LinearRegressionWithSGD. but I found that the count operation is very slow , just as show below, it seems get stuck.


   My spark version is 0.9, memory of each node is 80G. the size of dataset is about 8G., and I run in 30 nodes.

   Any suggestion is thankful .