Hi All,
I have check out on the pytorch-summary source code and find the input size is calculate as follow :
 # assume 4 bytes/number (float on cuda).
total_input_size = abs(np.prod(sum(input_size, ()))
                           * batch_size * 4. / (1024 ** 2.))

The 8GB memory seems like it will multiply those 2 tensors shape together :
224 * 224 * 3 * 224 * 224 * 3
Then *4  = 90634715136 / (1024^2) = 86436
which match the display.
So I misunderstand that it would get the input size by following the forward function.
To consider in my case , the input size of the model should be (224 * 244 * 6 * 4)/(1024^2) = 1.148MB ?
Thanks,
Dick