Multiple Sequential Reader vs Sequential Reader =============================================== Vanilla CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 6176KB/s 114K usec 1544 1 6902KB/s 120K usec 1725 2 7510KB/s 571K usec 1877 1 4564KB/s 680K usec 1141 4 9469KB/s 495K usec 2365 1 3198KB/s 410K usec 799 8 12011KB/s 1178K usec 2999 1 1366KB/s 818K usec 341 16 13285KB/s 1923K usec 3315 1 728KB/s 1816K usec 182 32 13555KB/s 3286K usec 3373 1 391KB/s 3212K usec 97 IO scheduler controller + CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 6622KB/s 109K usec 1655 1 6691KB/s 115K usec 1672 2 5502KB/s 693K usec 1375 1 6373KB/s 419K usec 1593 4 5751KB/s 987K usec 1435 1 6330KB/s 569K usec 1582 8 6969KB/s 1569K usec 1737 1 6086KB/s 120K usec 1521 16 7094KB/s 3140K usec 1766 1 5984KB/s 119K usec 1496 32 6621KB/s 6571K usec 1638 1 5850KB/s 113K usec 1462 dm-ioaband + CFQ ----------------------------------- [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 6788KB/s 109K usec 1697 1 6828KB/s 123K usec 1707 2 6615KB/s 492K usec 1653 1 5914KB/s 605K usec 1478 4 8116KB/s 410K usec 2027 1 4809KB/s 371K usec 1202 8 9277KB/s 1074K usec 2316 1 2864KB/s 756K usec 716 16 11013KB/s 1647K usec 2748 1 1815KB/s 1552K usec 453 32 11388KB/s 3301K usec 2832 1 861KB/s 2427K usec 215 io-throttle + CFQ ----------------------------------- BW limit group1=30 MB/s BW limit group2=30 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 6195KB/s 116K usec 1548 1 6993KB/s 109K usec 1748 2 7451KB/s 583K usec 1862 1 4516KB/s 433K usec 1129 4 9552KB/s 602K usec 2387 1 3001KB/s 583K usec 750 8 12257KB/s 861K usec 3060 1 1386KB/s 815K usec 346 16 13560KB/s 1659K usec 3382 1 718KB/s 1658K usec 179 32 13757KB/s 3482K usec 3422 1 409KB/s 3480K usec 102 BW limit group1=10 MB/s BW limit group2=10 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 4032KB/s 215K usec 1008 1 4076KB/s 170K usec 1019 2 4655KB/s 291K usec 1163 1 2891KB/s 212K usec 722 4 5872KB/s 417K usec 1466 1 1881KB/s 411K usec 470 8 7312KB/s 841K usec 1824 1 853KB/s 816K usec 213 16 7844KB/s 1728K usec 1956 1 503KB/s 1609K usec 125 32 7920KB/s 3417K usec 1969 1 249KB/s 3205K usec 62 BW limit group1=5 MB/s BW limit group2=5 MB/s [Multiple Sequential Reader] [Sequential Reader] nr Agg-bandw Max-latency Agg-iops nr Agg-bandw Max-latency Agg-iops 1 2377KB/s 110K usec 594 1 2415KB/s 120K usec 603 2 2759KB/s 222K usec 689 1 1709KB/s 220K usec 427 4 3314KB/s 420K usec 828 1 1163KB/s 414K usec 290 8 4060KB/s 901K usec 1011 1 527KB/s 816K usec 131 16 4324KB/s 1613K usec 1074 1 311KB/s 1613K usec 77 32 4320KB/s 3235K usec 1067 1 163KB/s 3209K usec 40