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Altera_Forum
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9 years ago

USB Bulk IN slow on Cyclone V

In our company we have a custom board using Cyclone V 5CSEBA2U19C8SN and USB 3300. We use Linux 4.1.15, build it with Buildroot 2015.11.1. One of my tasks is to setup USB Gadget subsystem. I use comb...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

Hi,

It's a bit difficult problem. I think that you are probably using the OTG core of the SoC system, but there are various kinds of buffering in the Linux system. Therefore, if you write data to these buffers, you can postpone later processing that takes time, but in case of reading, you need to prepare the data to be transferred. This preparation time may be one of the reasons for lowering the transfer rate.

Although it may not be easy, but using the kernel profiler (OProfile?) is one method to watch the kernel process.

Kazu