[dm-devel] [PATCH 1/1] block: Convert hd_struct in_flight from atomic to percpu
Brian King
brking at linux.vnet.ibm.com
Tue Jul 4 20:58:00 UTC 2017
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
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