• Rusty Russell's avatar
    virtio: harsher barriers for rpmsg. · 7b21e34f
    Rusty Russell authored
    We were cheating with our barriers; using the smp ones rather than the
    real device ones.  That was fine, until rpmsg came along, which is
    used to talk to a real device (a non-SMP CPU).
    
    Unfortunately, just putting back the real barriers (reverting
    d57ed95d) causes a performance regression on virtio-pci.  In
    particular, Amos reports netbench's TCP_RR over virtio_net CPU
    utilization increased up to 35% while throughput went down by up to
    14%.
    
    By comparison, this branch is in the noise.
    
    Reference: https://lkml.org/lkml/2011/12/11/22Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
    7b21e34f
virtio_mmio.c 12.6 KB