Intel® Distribution of OpenVINO™ Toolkit
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USB 2.0 bottleneck?

idata
Community Manager
377 Views

Hi all,

 

In my current configuration I'm using a raspberry pi 3 with the movidius ncs. Based on this article:

 

https://movidius.github.io/blog/ncs-rpi3-mobilenets/

 

It's possible to get >15FPS with a network with a size of 224_224. Now I'm using MobilenetSSD caffe implementation from NCS Appzoo folder and I can only get ~5FPS. Based on profiling data it could be much more faster. The network size in case of MobilenetSSD is 300_300, which results 300_300_3*16 bit = 4320000 bit = 540kB per frame, which is ~2.5MB/s in case of 5FPS. What do you think guys, is it possible that the USB 2.0 might be the bottleneck?

 

Best,

 

David
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2 Replies
idata
Community Manager
152 Views

Well it is simple math in my opinion. Raspbery pi shares EVERYTHING on one bus. This means the ONE usb 2.0 bus(which is split to 4 usb 2.0 ports) and the 100Gb/s ethernet port. If you are only using the usb bus for one thing, or the ethernet port without the usb ports, it will be around 11MB/s. But example if you download/upload with 5MB/s, you only have left 5-6MB/s for the usb2 port. I don't know your concept, but if you get your feed from the network, it sucks bandwidth from usb. And these are real numbers, because i download to my pi all the time at 11MB/s and copy files with average 10-13MB/s as well. Hope it helps.

idata
Community Manager
152 Views

Sorry it is 100Mb/s, but I think you realized it :)

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