• Stephan Gatzka's avatar
    firewire: net: Use posted writes · a74477db
    Stephan Gatzka authored
    Change memory region to ohci "middle address space". This effectively
    reduces the number of packets by 50%.
    
    [Stefan R.:]  This eliminates 1394 ack packets and improved throughput
    by a few percent in some tests with an S400a connection with and without
    gap count optimization.  Since firewire-net taxes the AR-req DMA unit of
    a FireWire controller much more than firewire-sbp2 (which uses the
    middle address space with PCI posted writes too), this commit also
    changes a related error printk into a ratelimited one as a precaution.
    
    Side note:  The IPv4-over-1394 drivers of Mac OS X 10.4, Windows XP SP3,
    and the Thesycon 1394 bus driver for Windows all use the middle address
    space too.
    Signed-off-by: default avatarStephan Gatzka <stephan@gatzka.org>
    Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
    a74477db
net.c 43.1 KB