1. 01 Mar, 2017 1 commit
    • Jason Wang's avatar
      vhost: introduce O(1) vq metadata cache · f8894913
      Jason Wang authored
      When device IOTLB is enabled, all address translations were stored in
      interval tree. O(lgN) searching time could be slow for virtqueue
      metadata (avail, used and descriptors) since they were accessed much
      often than other addresses. So this patch introduces an O(1) array
      which points to the interval tree nodes that store the translations of
      vq metadata. Those array were update during vq IOTLB prefetching and
      were reset during each invalidation and tlb update. Each time we want
      to access vq metadata, this small array were queried before interval
      tree. This would be sufficient for static mappings but not dynamic
      mappings, we could do optimizations on top.
      
      Test were done with l2fwd in guest (2M hugepage):
      
         noiommu  | before        | after
      tx 1.32Mpps | 1.06Mpps(82%) | 1.30Mpps(98%)
      rx 2.33Mpps | 1.46Mpps(63%) | 2.29Mpps(98%)
      
      We can almost reach the same performance as noiommu mode.
      Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
      Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      f8894913
  2. 27 Feb, 2017 11 commits
  3. 19 Feb, 2017 11 commits
  4. 18 Feb, 2017 1 commit
  5. 17 Feb, 2017 16 commits