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Participant kayas257
Participant
234 Views
Registered: ‎06-03-2018

What would be maximum DMA transfer speed to linux user space with Xilinx AXI DMA?

Hello folks,

 

I am very curious on how much maximum speed we can achieve with AXI DMA considering OS latency.

 

Thanks & Regards,

Kayas Ahmed

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3 Replies
169 Views
Registered: ‎04-20-2017

Re: What would be maximum DMA transfer speed to linux user space with Xilinx AXI DMA?

Axi lite write to start the ddma takes a few us... 

Write to memory I saw around 500mb/sec..

Getting it into userspace is a different game... It depends how the addresses you are writing to with dma  is exposed to linux

Continuous memory allocation and know to userspace is fast (need Kernel driver). The fast and easy way is to use DDr adresses excluded from Linux completely and map over mmap to userspace... It that case you get around 40mb/sec on zynq7000 (I read that it has to do with caching, but not entirely sure why) 

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Participant kayas257
Participant
154 Views
Registered: ‎06-03-2018

Re: What would be maximum DMA transfer speed to linux user space with Xilinx AXI DMA?

Hello,

Thanks for the info, I am trying the same to get data at a higher rate to userspace with custom kernel driver and DMA.

 

 

Thanks & Regrads,

Kayas Ahmed

 

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129 Views
Registered: ‎04-20-2017

Re: What would be maximum DMA transfer speed to linux user space with Xilinx AXI DMA?

checkout that github project...I plan to use it in the future for solving exactly the same problem

https://github.com/ikwzm/udmabuf

 

 

 

 

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