On 7/22/22 02:51, Wang You wrote:
The test hardware is: Kunpeng-920, HW-SAS3508+(MG04ACA400N * 2), RAID0.
What is MG04ACA400N? The test results suggest that it is an SSD but this is something that should be mentioned explicitly.
- The test hardware is: Hygon C86, MG04ACA400N
What is 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 above results are low enough such that these could come from a hard disk. However, the test results are hard to interpret since the I/O pattern is neither perfectly sequential nor perfectly random (32 sequential jobs). Please provide separate measurements for sequential and random I/O.
The above results show that this patch makes reading from a hard disk slower. Isn't the primary use case of mq-deadline to make reading from hard disks faster? So why should these two patches be applied if these slow down reading from a hard disk?
Thanks, Bart.
