• K
    Drivers: net-next: hyperv: Increase the size of the sendbuf region · 06b47aac
    KY Srinivasan 提交于
    Intel did some benchmarking on our network throughput when Linux on Hyper-V
    is as used as a gateway. This fix gave us almost a 1 Gbps additional throughput
    on about 5Gbps base throughput we hadi, prior to increasing the sendbuf size.
    The sendbuf mechanism is a copy based transport that we have which is clearly
    more optimal than the copy-free page flipping mechanism (for small packets).
    In the forwarding scenario, we deal only with MTU sized packets,
    and increasing the size of the senbuf area gave us the additional performance.
    For what it is worth, Windows guests on Hyper-V, I am told use similar sendbuf
    size as well.
    
    The exact value of sendbuf I think is less important than the fact that it needs
    to be larger than what Linux can allocate as physically contiguous memory.
    Thus the change over to allocating via vmalloc().
    
    We currently allocate 16MB receive buffer and we use vmalloc there for allocation.
    Also the low level channel code has already been modified to deal with physically
    dis-contiguous memory in the ringbuffer setup.
    
    Based on experimentation Intel did, they say there was some improvement in throughput
    as the sendbuf size was increased up to 16MB and there was no effect on throughput
    beyond 16MB. Thus I have chosen 16MB here.
    
    Increasing the sendbuf value makes a material difference in small packet handling
    
    In this version of the patch, based on David's feedback, I have added
    additional details in the commit log.
    Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    06b47aac
hyperv_net.h 29.4 KB