On 07/03/2017 08:20 PM, Ming Lei wrote: >> Right. So the two modes I'm running in are: >> >> 1. 80 null_blk devices, each with one submit_queue, with one fio job per null_blk device, >> so 80 threads total. 80 logical CPUs >> 2. 1 null_blk device, with 80 submit_queues, 80 fio jobs, 80 logical CPUs. >> >> In theory, the two should result in similar numbers. >> >> Here are the commands and fio configurations: >> >> Scenario #1 >> modprobe null_blk submit_queues=80 nr_devices=1 irqmode=0 >> >> FIO config: >> [global] >> buffered=0 >> invalidate=1 >> bs=4k >> iodepth=64 >> numjobs=80 >> group_reporting=1 >> rw=randrw >> rwmixread=100 >> rwmixwrite=0 >> ioengine=libaio >> runtime=60 >> time_based >> >> [job1] >> filename=/dev/nullb0 > > IMO it should be more reasonable to use single null_blk with 80 queues > via setting submit_queues as 80 than simply 80 null_blks. So suggest to switch > to test 80 queues in your future test. That should be what my Scenario #1 covers. Thanks, Brian -- Brian King Power Linux I/O IBM Linux Technology Center
