Hi all, I just run an experiment in SSD RAID0, I am running a read I/O with write noise in the background for 30 seconds. I use numjobs=64 to simulate intense write noise. But I want to cap the write noise to certain IOPS using `rate_iops` parameter. I know that the rate_iops parameter capped the iops per job not the cumulative iops from all the jobs. But I found something unusual here, when I set the write rate_iops=100k (a very large iops) the actual iops reach 1066k, so I can assume that each job's iops is around 1066k/64 = 16657. The P99 read latency from this experiment is 162530us. However, when I set the rate_iops=16657 with the same numjobs, the cumulative iops is close to the previous measurement (1046k). But, the P99 read latency is 68682us, way smaller than the previous measurement. I am expecting similar large read latencies from both measurements since the cumulative write iops is the same, around 1050k. But the results show the opposite. Here is the jobfile for the first exp: https://raw.githubusercontent.com/fadhilkurnia/research/master/v1-false/raid_test_100kwps.fio here is the result from the first exp: https://raw.githubusercontent.com/fadhilkurnia/research/master/v1-false/raid_test_100kwps.output and here is the jobfile for the last exp: https://raw.githubusercontent.com/fadhilkurnia/research/master/v2/raid_test_1066kwps.fio result from the last exp: https://raw.githubusercontent.com/fadhilkurnia/research/master/v2/raid_test_1066kwps.output I don't fully understand how rate_iops works, so is this problem related to it? or it is because I set the rate too big? and is there any explanation of why this happened?
