Multiple Sequential Reader vs Sequential Reader =============================================== Vanilla CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 6325KB/s 6325KB/s 6176KB/s 114K usec 1 6902KB/s 120K usec 2 4588KB/s 3102KB/s 7510KB/s 571K usec 1 4564KB/s 680K usec 4 3242KB/s 1158KB/s 9469KB/s 495K usec 1 3198KB/s 410K usec 8 1775KB/s 459KB/s 12011KB/s 1178K usec 1 1366KB/s 818K usec 16 943KB/s 296KB/s 13285KB/s 1923K usec 1 728KB/s 1816K usec 32 511KB/s 148KB/s 13555KB/s 3286K usec 1 391KB/s 3212K usec IO scheduler controller + CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 6781KB/s 6781KB/s 6622KB/s 109K usec 1 6691KB/s 115K usec 2 3758KB/s 1876KB/s 5502KB/s 693K usec 1 6373KB/s 419K usec 4 2100KB/s 671KB/s 5751KB/s 987K usec 1 6330KB/s 569K usec 8 1023KB/s 355KB/s 6969KB/s 1569K usec 1 6086KB/s 120K usec 16 520KB/s 130KB/s 7094KB/s 3140K usec 1 5984KB/s 119K usec 32 245KB/s 86KB/s 6621KB/s 6571K usec 1 5850KB/s 113K usec dm-ioaband + CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 6951KB/s 6951KB/s 6788KB/s 109K usec 1 6828KB/s 123K usec 2 3949KB/s 2825KB/s 6615KB/s 492K usec 1 5914KB/s 605K usec 4 2532KB/s 1389KB/s 8116KB/s 410K usec 1 4809KB/s 371K usec 8 1443KB/s 658KB/s 9277KB/s 1074K usec 1 2864KB/s 756K usec 16 856KB/s 312KB/s 11013KB/s 1647K usec 1 1815KB/s 1552K usec 32 634KB/s 94KB/s 11388KB/s 3301K usec 1 861KB/s 2427K usec io-throttle + CFQ ----------------------------------- BW limit group1=30 MB/s BW limit group2=30 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 6343KB/s 6343KB/s 6195KB/s 116K usec 1 6993KB/s 109K usec 2 4583KB/s 3046KB/s 7451KB/s 583K usec 1 4516KB/s 433K usec 4 2945KB/s 1324KB/s 9552KB/s 602K usec 1 3001KB/s 583K usec 8 1804KB/s 473KB/s 12257KB/s 861K usec 1 1386KB/s 815K usec 16 942KB/s 265KB/s 13560KB/s 1659K usec 1 718KB/s 1658K usec 32 462KB/s 143KB/s 13757KB/s 3482K usec 1 409KB/s 3480K usec BW limit group1=10 MB/s BW limit group2=10 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 4128KB/s 4128KB/s 4032KB/s 215K usec 1 4076KB/s 170K usec 2 2880KB/s 1886KB/s 4655KB/s 291K usec 1 2891KB/s 212K usec 4 1912KB/s 888KB/s 5872KB/s 417K usec 1 1881KB/s 411K usec 8 1032KB/s 432KB/s 7312KB/s 841K usec 1 853KB/s 816K usec 16 540KB/s 259KB/s 7844KB/s 1728K usec 1 503KB/s 1609K usec 32 291KB/s 111KB/s 7920KB/s 3417K usec 1 249KB/s 3205K usec BW limit group1=5 MB/s BW limit group2=5 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 2434KB/s 2434KB/s 2377KB/s 110K usec 1 2415KB/s 120K usec 2 1639KB/s 1186KB/s 2759KB/s 222K usec 1 1709KB/s 220K usec 4 1114KB/s 648KB/s 3314KB/s 420K usec 1 1163KB/s 414K usec 8 567KB/s 366KB/s 4060KB/s 901K usec 1 527KB/s 816K usec 16 329KB/s 179KB/s 4324KB/s 1613K usec 1 311KB/s 1613K usec 32 178KB/s 70KB/s 4320KB/s 3235K usec 1 163KB/s 3209K usec