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XIO2213B throughput when connect two 1394 devices

Terry Wu
Expert 1680 points

Other Parts Discussed in Thread: XIO2213B

Dear Experts,

This chip PCIe GEN 1 x1 is 2.5Gbps , If we connect two 1394b HDD. It should be no bandwidth problem,right ?

In fact, we connect single 1394b HDD , max throughput is 80 MB/s using Crystal Diskmark tool.

But problem is when we connect 2st 1394b device. data rate from 80MB/s drop to 40MB/s..... XIO2213B EVM get same result.

O/S is Win7

Please kindly share your experience. TKS !

  • 0
    TI__Guru* 76130 points

    Hello,

    We are going to replicate the issue and provide feedback.

    Have you tried with different HDDs?

    Regards.

  • 0 in reply to Elias Villegas M.
    Expert 1680 points

    Dear Sir,

    Sorry that no more 1394B devices on hand to verify it.

    Can you  reduplicate it  in your side ? 

    Is it no problem to let two 1394B devices full speed working under XIO2213B downstream ports ?

    TKS!

  • 0 in reply to Terry Wu
    TI__Mastermind 36085 points

    Hello terry,

        There is no problem to connect two 1394b devices under the XIO2213b, however the throughput depends on several factors like the PCIe bus load, the system load, the compatibility between devices and the speed of the HDD. The 80MB/s data looks good as an optimal bus speed, now if you connect more than  one device remember that the OHCI controller will share the total bandwidth available, so is expected to see a drop on the throughput.

    Regards,

    Diego. 

  • 0 in reply to Diego Cortes
    Expert 1680 points

    Dear Diego,

    We try to use SSD replace system HDD , this is want to ignore system HDD bandwidth problem but also get same result.

    Just plug 2st 1394b HDD and don't access it . 1st HDD speed drop from 80MB/s to 1/2 ( 40MB/s) <= Is it reasonable ?

    BTW. Do you have  test data for our reference ?

    Many thanks your support !

  • 0 in reply to Terry Wu
    TI__Mastermind 36085 points

    Hello Terry,

        When you said "Just plug 2st 1394b HDD and don't access it" what you mean is that this second device is not being recognized by the system and at the same time the speed from the 1st HDD drops about 1/2, is it correct?

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    Expert 1680 points

    Dear Diego,

    Yes ! Just need to plug 2st 1394 HDD could see throughput drop .

    Do you have devices can help to reduplicate ?

    I also need to know can XOP2213B fulfill three downstream ports if no bottleneck problem on upstream PCIe port .Like: USB 3.0 Host or Hub.

    Thanks in advance !

  • 0 in reply to Terry Wu
    TI__Mastermind 36085 points

    Hello Terry,

       We do not have devices to reproduce the issue, now the initial 80MB/s is a good throughput, however behavior of the 2nd disc is very unusual. Coud you confirm more cases of the issue?

       -Only 2nd HDD connected. 

       -Connect first the 2nd HDD and then the first one.

    Regarding to the possible bottleneck, there is nothing to worry about, since the 1394b data rate is lower than PCIe.

    Regards,

    Diego.