I wrote a article about this subject with how 3140 and 3160 latency levels compare and also how to calculate the theoretical maximum IOps based on type and quantity of hard disk in a RAID-DP based aggregate.
you will need to be in Priveleged Mode - Advanced.
From there you can work out your read/write % and actually work out how to fix it, DO NOT Involve netapp support - they will read off a script and ask for a perfstat then a week later they will say "buy more disk" rather than, oh you have high latency? maybe you need to re-balance the aggregate? or reallocate or add jumbo frames or anything constructive lol.