arm64 swap-related question

Hello,

What's the default granularity with swapping on recent -current 
on arm64?

ie. whats the smallest size of data that is swapped out. 1k? 4k? Where
can I find this info? Can it be set/tuned? How to see what it currently is?
I'd like to set it to 32k if possible. Read performance on this disk 
for swap tops out at 60MB/s with a 32k block size.

For bs=512 it's 1349 kB/s
For bs=4k it's 11MB/s

context: the thing I'm trying to work around is poor swap performance 
on this arch/hardware.
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