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Altera_Forum's avatar
Altera_Forum
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12 years ago

Altera DMA throughput calculation?

I have a Cyclone V and I am connecting a DMA read master to an On Chip RAM and the write master to the DDR Controller.

It seems like I am getting 600MB/sec throughput, which looks too much! Is it possible or is there something wrong? How can I calc the max throughput?

The system is running at 100Mhz and my data width is 64 bits. Theorically I could achieve (64*100.000.000)/8) 800MB/sec. So 600MB/sec looks possible. Is this right? I am comparing the onchip data with the ddr data and it matches but it looks to good to be true...

Cheers

1 Reply

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

    First time I've seen someone ask if they're getting too much throughput. :)

    The fact that you're checking it on-chip seems promising. The controller does a lot of things to help efficiency. The high-level stuff in the handbook includes:

    Command and Data Reordering

    Bank Management

    Streaming Reads and Writes

    Bank Interleaving

    Predictive Bank Management

    Build-in Burst Adaptor

    etc.

    Efficiency is always dependent on the reads and writes, but a lot of this smooths out the low corner-cases for much better efficiency.