Uploaded image for project: 'Lustre'
  1. Lustre
  2. LU-11618

implement ladvise rpc_size for optimized performance



    • New Feature
    • Status: Open
    • Minor
    • Resolution: Unresolved
    • None
    • None
    • None
    • 9223372036854775807


      Originally, the maximum RPC size for bulk I/O can be controlled by
      per-OSC parameter max_pages_per_rpc. Whenever it is possible, the
      OSC will do bulk I/O as large as max_pages_per_rpc for better
      performance. Thus, changing the value of max_pages_per_rpc usually
      affects the I/O performance a lot. However, due to the I/O pattern
      difference, not all applications can get the best performance with
      the same value of max_pages_per_rpc.

      We want to add a new type of ladvise to enabling applications to
      set different RPC sizes for different files. max_pages_per_rpc is
      still the upper limit of the RPC size in all cases. And new
      parameter default_pages_per_rpc has been added and its value is
      the default RPC size. If a ladvise of rpc_size is given to a file,
      the RPC size of the file will be changed according to the ladvise.
      But the maximum RPC size will still limited by max_pages_per_rpc.

      The RPC size of a file configured by ladivse is neither a global
      attribute nor a persistent attribute. Each client may have
      different RPC size for the same file. And the RPC size of the file
      will change back to default_pages_per_rpc when the hint kept in
      memory is lost due to memory shrinkage.


        Issue Links



              lixi_wc Li Xi
              lixi_wc Li Xi
              0 Vote for this issue
              5 Start watching this issue