Re: [PATCH 2/2] block/mq-deadline: Prioritize first request

[Wang You]

>> The test hardware is:
>> Kunpeng-920, HW-SAS3508+(MG04ACA400N * 2), RAID0.
> Please also provide performance numbers for a single hard disk and with 
> no RAID controller between the host and the hard disk.

> Thanks,

> Bart.

Hi,

Yesterday I found another server without raid controller to test a same HDD, 
but the performance(The data is not stable, so I tested it many times) wasn't 
what I expected.

Also I tested a SSD with raid contriller on a previous Kunpeng server and 
the performance improved, but that's not always the case with SSDs on 
other servers.

This may indicate that the raid controller plays an important role in this, 
so I'm not sure if this patch really has the desired effect.

Thanks,

Wang.


The test hardware is:
Hygon C86, MG04ACA400N

The test command is:
fio -ioengine=psync -lockmem=1G -buffered=0 -time_based=1 -direct=1 -iodepth=1 
-thread -bs=512B -size=110g -numjobs=32 -runtime=300 -group_reporting 
-name=read -filename=/dev/sdc -ioscheduler=mq-deadline -rw=read[,write,rw]

The following is the test data:
origin/master:
read iops: 15463	write iops: 5949	rw iops: 574,576

nr_sched_batch = 1:
read iops: 15082	write iops: 6283	rw iops: 783,786

nr_sched_batch = 1, use deadline_head_request:
read iops: 15368	write iops: 6575	rw iops: 907,906


The test hardware is:
Kunpeng-920, HW-SAS3508 + Samsung SSD 780, RAID0.

The test command is:
fio -ioengine=psync -lockmem=1G -buffered=0 -time_based=1 -direct=1 -iodepth=1 
-thread -bs=512B -size=110g -numjobs=16 -runtime=300 -group_reporting 
-name=read -filename=/dev/sda -ioscheduler=mq-deadline -rw=read[,write,rw]

The following is the test data:
origin/master:
read iops: 115399       write iops: 136801      rw iops: 58082,58084

nr_sched_batch = 1, use deadline_head_request:
read iops: 136473       write iops: 184646      rw iops: 56460,56454