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Altera_Forum's avatar
Altera_Forum
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18 years ago

can EP2C35+Nios+DM9000 provide 50Mbps throughput?

I am an embedded engineer and used DM9000 NIC with EP2C35+Nios+uClinux-2.6.11 in our project, we find DM9000 only provides

14~15Mpbs transfer throughput! Can DM9000 provides higher throughput? System clock in our project is 50MHz, feed DM9000 with

25MHz clock. Anyone used DM9000 can get 50Mpbs throughput? need your help!

Any successful story using DM9000 get 50Mbps is helpful to me!

3 Replies

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

    Hello,

    I consider 15 Mpbs a realistic performance, if the data is propagated through a software IP stack without hardware accelaretation.

    Regards,

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

    Thanks Frank for you reply!

    So can you give me some advice on how to implement hardware accelaration?

    I found <Nios II Ethernet Acceleration Design Example> from site of Altera, but I

    am not sure the way given by above material has magic power to acclerate NIC

    throughput from 15Mbps to 50Mbps!

    Best Regards

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

    Hello Haishan,

    I think, the "Ethernet Acceleration Example" can help to understand the system characteristics that limit network throughput, although it uses different network controller and OS than you do. The benchmark data from AN440 give a general idea of what could be expected. It seems to indicate, that besides data processing within the TCP stack (e. g. calculating checksums) also network processor interface (in case of LAN91C111 that should be roughly comparable with DM9000) could be a bottleneck. This is somewhat surprizing, cause these devices can transfer data at network speed to and from conventional processors.

    If the DM9000 interface shows similar behaviour as the LAN91C111, the intended 50 MBps seem unattainable. I also wonder, if uClinux could be easily modified to use hardware acceleration and the said "zero copy" operation. It may be easier to design a "hardware" TCP socket independent of Nios and uClinux.

    Best regards,

    Frank