LMDB slower than using ImageData

[Barry]

Hi

So i ran using ImageData, feeding in 3 channel png images.

That took about 22 seconds on average to do 5 iterations in my network.

Then I ran using LMDB Data, feeding in 8 channel images

That took about 190 seconds on average to do 5 iterations in the same network.

I know my comparison is not quite 1 to 1 because with the png files I am using 3 channel images, and with the LMDB files I am using 8 channel images.

But I wouldn't expect the difference to be so much worse

I also get 2 or 3 "blocking_queue.cpp:50] Waiting for data" messages between every iteration, when using the LMDB files, never with the png files.

Is that normal?

Both the png and lmdb files are on the same hard drive, which is the computers main internal hard drive

Any thoughts?

[Barry]

As an additional note, the longer I train using the LMDB, the more time each batch takes. This was not the case when using png files.

The 5 iterations that was taking about 3 minutes originally is now taking 9 minutes.

Memory usage is staying constant, and I am not touching the machine, nothing else is running.