Re: [PATCH v2 00/12] Improve Raid5 Lock Contention
From: Logan Gunthorpe
Date: Mon Apr 25 2022 - 11:41:35 EST
On 2022-04-24 02:00, Guoqing Jiang wrote:
> On 4/22/22 12:02 AM, Logan Gunthorpe wrote:
>> On 2022-04-21 02:45, Xiao Ni wrote:
>>> Could you share the commands to get the test result (lock contention
>>> and performance)?
>> Sure. The performance we were focused on was large block writes. So we
>> setup raid5 instances with varying number of disks and ran the following
>> fio script directly on the drive.
>> (We also played around with tuning this but didn't find substantial
>> changes once the bottleneck was hit)
> Nice, I suppose other IO patterns keep the same performance as before.
>> We tuned md with parameters like:
>> echo 4 > /sys/block/md0/md/group_thread_cnt
>> echo 8192 > /sys/block/md0/md/stripe_cache_size
>> For lock contention stats, we just used lockstat; roughly like:
>> echo 1 > /proc/sys/kernel/lock_stat
>> fio test.fio
>> echo 0 > /proc/sys/kernel/lock_stat
>> cat /proc/lock_stat
>> And compared the before and after.
> Thanks for your effort, besides the performance test, please try to run
> mdadm test suites to avoid regression.
Yeah, is there any documentation for that? I tried to look into it but
couldn't figure out how it's run.
I do know that lkp-tests has run it on this series as I did get an error
from it. But while I'm pretty sure that error has been resolved, I was
never able to figure out how to run them locally.