ceph/src/boost/boost/sort/spreadsort/detail/constants.hpp

   1 //constant definitions for the Boost Sort library
   2
   3 //          Copyright Steven J. Ross 2001 - 2014
   4 // Distributed under the Boost Software License, Version 1.0.
   5 //    (See accompanying file LICENSE_1_0.txt or copy at
   6 //          http://www.boost.org/LICENSE_1_0.txt)
   7
   8 //  See http://www.boost.org/libs/sort for library home page.
   9 #ifndef BOOST_SORT_SPREADSORT_DETAIL_CONSTANTS
  10 #define BOOST_SORT_SPREADSORT_DETAIL_CONSTANTS
  11 namespace boost {
  12 namespace sort {
  13 namespace spreadsort {
  14 namespace detail {
  15 //Tuning constants
  16 //This should be tuned to your processor cache;
  17 //if you go too large you get cache misses on bins
  18 //The smaller this number, the less worst-case memory usage.
  19 //If too small, too many recursions slow down spreadsort
  20 enum { max_splits = 11,
  21 //It's better to have a few cache misses and finish sorting
  22 //than to run another iteration
  23 max_finishing_splits = max_splits + 1,
  24 //Sets the minimum number of items per bin.
  25 int_log_mean_bin_size = 2,
  26 //Used to force a comparison-based sorting for small bins, if it's faster.
  27 //Minimum value 1
  28 int_log_min_split_count = 9,
  29 //This is the minimum split count to use spreadsort when it will finish in one
  30 //iteration.  Make this larger the faster std::sort is relative to integer_sort.
  31 int_log_finishing_count = 31,
  32 //Sets the minimum number of items per bin for floating point.
  33 float_log_mean_bin_size = 2,
  34 //Used to force a comparison-based sorting for small bins, if it's faster.
  35 //Minimum value 1
  36 float_log_min_split_count = 8,
  37 //This is the minimum split count to use spreadsort when it will finish in one
  38 //iteration.  Make this larger the faster std::sort is relative to float_sort.
  39 float_log_finishing_count = 4,
  40 //There is a minimum size below which it is not worth using spreadsort
  41 min_sort_size = 1000 };
  42 }
  43 }
  44 }
  45 }
  46 #endif