Multiple Random Writer vs Random Reader =============================================== Vanilla CFQ ----------------------------------- [Multiple Random Writer] [Random Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 64018KB/s 64018KB/s 62517KB/s 353K usec 1 190KB/s 96 msec 2 35298KB/s 35257KB/s 68899KB/s 208K usec 1 76KB/s 2416 msec 4 16387KB/s 14662KB/s 60630KB/s 3746K usec 1 106KB/s 2308K usec 8 5106KB/s 3492KB/s 33335KB/s 2995K usec 1 193KB/s 2292K usec 16 3676KB/s 3002KB/s 51807KB/s 2283K usec 1 72KB/s 2298K usec 32 2169KB/s 1480KB/s 56882KB/s 1990K usec 1 35KB/s 1093 msec IO scheduler controller + CFQ ----------------------------------- [Multiple Random Writer] [Random Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 20369KB/s 20369KB/s 19892KB/s 877K usec 1 255KB/s 137K usec 2 14347KB/s 14288KB/s 27964KB/s 1010K usec 1 228KB/s 117K usec 4 6996KB/s 6701KB/s 26775KB/s 1362K usec 1 221KB/s 180K usec 8 2849KB/s 2770KB/s 22007KB/s 2660K usec 1 250KB/s 485K usec 16 1463KB/s 1365KB/s 22384KB/s 2606K usec 1 254KB/s 115K usec 32 799KB/s 681KB/s 22404KB/s 2879K usec 1 266KB/s 107K usec dm-ioaband + CFQ ----------------------------------- [Multiple Random Writer] [Random Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 62355KB/s 62355KB/s 60893KB/s 82885 usec 1 197KB/s 118 msec 2 34853KB/s 34848KB/s 68068KB/s 625K usec 1 65KB/s 2335 msec 4 16526KB/s 16184KB/s 63662KB/s 1005K usec 1 69KB/s 1540 msec 8 6303KB/s 4508KB/s 39472KB/s 2037K usec 1 180KB/s 1479K usec 16 2762KB/s 2564KB/s 41654KB/s 820K usec 1 59KB/s 3350 msec 32 700KB/s 595KB/s 19668KB/s 2440K usec 1 17KB/s 4090 msec io-throttle + CFQ ----------------------------------- BW limit group1=30 MB/s BW limit group2=30 MB/s [Multiple Random Writer] [Random Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 21920KB/s 21920KB/s 21406KB/s 1017K usec 1 353KB/s 432K usec 2 14291KB/s 9626KB/s 23357KB/s 1832K usec 1 362KB/s 177K usec 4 7130KB/s 5135KB/s 24736KB/s 1336K usec 1 348KB/s 425K usec 8 3165KB/s 2949KB/s 23792KB/s 2133K usec 1 336KB/s 146K usec 16 1653KB/s 1406KB/s 23694KB/s 2198K usec 1 337KB/s 115K usec 32 793KB/s 717KB/s 23198KB/s 2195K usec 1 330KB/s 192K usec BW limit group1=10 MB/s BW limit group2=10 MB/s [Multiple Random Writer] [Random Reader] nr Max-bandw Min-bandw Agg-bandw Max-latency nr Agg-bandw Max-latency 1 7903KB/s 7903KB/s 7718KB/s 1037K usec 1 474KB/s 103K usec 2 4496KB/s 4428KB/s 8715KB/s 1091K usec 1 450KB/s 553K usec 4 2153KB/s 1827KB/s 7914KB/s 2042K usec 1 458KB/s 108K usec 8 1129KB/s 1087KB/s 8688KB/s 1280K usec 1 432KB/s 98215 usec 16 606KB/s 527KB/s 8668KB/s 2303K usec 1 426KB/s 90609 usec 32 312KB/s 259KB/s 8599KB/s 2557K usec 1 441KB/s 95283 usec