llil4map start                                             
use OpenMP             ( old )    ( next )     ( buf )    (2024-07)
memory consumption     36.6 GB     17.5 GB     16.0 GB     15.0 GB
use boost sort
get properties         12.967s     11.527s     10.402s      7.705s
map to vector           3.244s      1.252s      1.211s      0.743s
vector stable sort     10.265s      8.708s      8.161s      6.546s
write stdout            1.410s      1.388s      1.386s      2.273s
total time             27.887s     22.877s     21.163s     17.268s
    count lines      970195200
    count unique     295755152
29612263 5038456270

       real time     0m43.973s   0m24.872s   0m21.909s   0m17.683s
       user         25m08.532s  22m58.120s  20m56.492s  16m48.601s
       sys           0m55.602s   0m48.783s   0m11.551s   0m08.647s

Note: 2024-07 llil4map_buf2.cc