Thanks for you reply,
I am using local HDD.
After timing out the data I found that on average its taking like this,
#data loading time
data_time.val=0.000
data_time.avg=0.117
measure elapsed time
batch_time.val=0.075
batch_time.avg=0.233
I also made those changes which you have suggested but could’t make any improvement in GPU utilization(still 0 %).