1. 08 Oct, 2009 1 commit
    • Eric Dumazet's avatar
      udp: dynamically size hash tables at boot time · f86dcc5a
      Eric Dumazet authored
      UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for
      several setups.
      
      4000 active UDP sockets -> 32 sockets per chain in average. An
      incoming frame has to lookup all sockets to find best match, so long
      chains hurt latency.
      
      Instead of a fixed size hash table that cant be perfect for every
      needs, let UDP stack choose its table size at boot time like tcp/ip
      route, using alloc_large_system_hash() helper
      
      Add an optional boot parameter, uhash_entries=x so that an admin can
      force a size between 256 and 65536 if needed, like thash_entries and
      rhash_entries.
      
      dmesg logs two new lines :
      [    0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes)
      [    0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes)
      
      Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non
      debugging spinlocks.
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f86dcc5a
  2. 07 Oct, 2009 39 commits