Port-xen archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: Dom0 bad network performance



Suggestions

  - post the dmesg lines for the network interface (minus mac addr, if
    you are paranoid) from both GENERIC and XEN3_DOM0.   It is
    possible that this issue is related to not only Xen but
    also the driver for the particular network interface

  - run iperf to localhost both ways.  That exercises TCP and the
    user/kernel path for data, but not the physical network interface

  - For any network issues, I recommend doing "netstat -s" before and
    after a test, and then diffing the results, trying to understand the
    origin of all counter changes.   For example in your case, there
    probably shouldn't be any dropped packets.  So if that increments --
    or more importantly some other counter none of us have thought
    about -- that's interesting.

  - Run iperf in UDP mode.  This separates TCP's congestion reaction
    from ability to push packets.

  - This is hard, and probably not that useful in this case, but
    graphics/xplot-devel has a script tcpdump2xplot, which probably
    needs updating for tcpdump format drift, that is really useful for
    visualizing tcp behavior.  But if netstat -s shows no drops, this
    isn't so useful here.

Attachment: signature.asc
Description: PGP signature



Home | Main Index | Thread Index | Old Index