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Altera_Forum's avatar
Altera_Forum
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13 years ago

Bandwidth Calculation of PCIe data Transfer for arria II speed -x1

Hi,

i want to know what is the bandwidth of PCIe data transfer for ARRIA II GX FPGA Board with the Chained DMA Example provided by Altera.When testing with the GUI(which has Jungo drivers for PCIe),it shows as 200MB/s. But actually the speed is much lesser.I calculated on the write_enables generated per second.

Regards

Santosh

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    The attainable throughput depends a lot on the size of the PCIe requests.

    Unless the request comes from some DMA engine that is adequately tied to the PCIe interface throughput will be very bad.

    I'm not sure the typical x86 PC has anything that can generate reasonable length PCIe requests.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Hi,

    I am using Chained DMA Engine example of Altera, which tested for DMA read (PC reading data from FPGA)shows speed as 178MB/s.But the write enables generated by DMA Example is very less i.e 25k/sec. so total throuput comes to 25k *64 Bits =1.6 Mbits/sec.

    So which is the correct speed?