Hi, When I am using fio to do some tests, I find a problem. I am using a client with a 10Gb NIC to do the test case of sequential read, and the configuration file is below: //version 2.0.8 global] iodepth=256 runtime=600 ioengine=libaio direct=1 size=30g filename=/dev/vdb ramp_time=10 [seq-read-64k] rw=read bs=64k iodepth_batch_submit=8 iodepth_batch_complete=8 we know the bandwidth can reach nearly 1100MB/s without the parameter of rate. It will finish fio in about 30 seconds, because the size is 30g. first, when I set ramp_time to 10, the fio result is below: seq-read-64k: (groupid=0, jobs=1): err= 0: pid=26840 read : io=20016MB, bw=1105.8MB/s, iops=17677 , runt= 18102msec second, when I set ramp_time to 35, the fio result is below: seq-read-64k: (groupid=0, jobs=1): err= 0: pid=26861 read : io=30720MB, bw=1102.3MB/s, iops=17636 , runt= 27870msec According to these, we can summary: 1. When we set ramp_time less than the time of fio finish read(we call it fftime for short), then Runt = fftime - ramptime 2. When we set ramp_time greater than the time of fio finish read(we call it fftime for short), then Runt = fftime My requirement is: I want to use ramp time to warm up 50 seconds, and then collect iostat data, but fio has finished after 30 seconds, so I will collect all empty data. Could we not calculate time and io size during ramp time in runt time, or do I have some mistakes to understand it? -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
