Scalability issue with multiple NVMe Devices with one core

[Roy Shterman]

On 10/13/2016 5:18 PM, Keith Busch wrote:
> On Thu, Oct 13, 2016 at 08:44:37AM +0300, Roy Shterman wrote:
>> scenario is when running traffic over 1 NVMe Device with 1 core I'm getting
>> X IOPS and Y% core utilization.
>>
>> In my perception, when adding more NVMe Devices I should see some linearity
>> of the above results, but I'm getting only a small improvement in IOPS and
>> still not getting 100% (or closer ) in CPU utilization.
>>
>> Any suggestions?
> How are you generating IO?

fio --group_reporting --rw=randread --bs=4k --numjobs=1 --ramp_time=30 
--iodepth=1 --runtime=300 --direct=1 --time_based --loops=1 
--ioengine=libaio --invalidate=1 --randrepeat=1 --norandommap --exitall 
--name task_nvme0n1 --filename=/dev/nvme0n1