Messages in this thread |  | | Subject | Re: [PATCH v2 00/12] Improve Raid5 Lock Contention | From | Guoqing Jiang <> | Date | Sun, 24 Apr 2022 16:00:15 +0800 |
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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. > > [simple] > filename=/dev/md0 > ioengine=libaio > rw=write > direct=1 > size=8G > blocksize=2m > iodepth=16 > runtime=30s > time_based=1 > offset_increment=8G > numjobs=12 >  > (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[1]; 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.
Thanks, Guoqing
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