A very, very strange result on MobileNet

[ZinuoCai]

I have recently used your code to evaluate mobilenet. My results show that GPU's performance is not as good as CPU's.

Here are my environments.

mxnet == 1.7.0
Ununtu 20.1
CUDA  10.2
Nvidia GTX 1070 Ti

Here my CPU results.

start mobilenet1.0 speed benchmark
mxnet: 0 time 5.468854904174805
mxnet: 1 time 5.232152938842773
mxnet: 2 time 5.269920825958252
mxnet: 3 time 5.603036880493164
mxnet: 4 time 5.499334335327148
mxnet: 5 time 5.205817222595215
mxnet: 6 time 5.577330589294434
mxnet: 7 time 5.659034252166748
mxnet: 8 time 5.7265305519104
mxnet: 9 time 6.112978458404541
mxnet: mobilenet1.0 5.205774307250977 5.535458087921143 6.112930774688721

Here my GPU results.

start mobilenet1.0 speed benchmark
mxnet: 0 time 40.76141119003296
mxnet: 1 time 40.58210611343384
mxnet: 2 time 41.749138832092285
mxnet: 3 time 40.48752307891846
mxnet: 4 time 40.23917198181152
mxnet: 5 time 40.33033847808838
mxnet: 6 time 40.38513660430908
mxnet: 7 time 40.24947166442871
mxnet: 8 time 40.08643388748169
mxnet: 9 time 39.98572111129761
mxnet: mobilenet1.0 39.98570203781128 40.48562288284302 41.74911975860596