I'm trying to put together a simple util that will help me during
performance tuning, It will grab a bunch of values from different
snapshots and the db/dbm cfg, and print out different values, and if a
certain threshold value is reached, some information of which parameter
that might be increased/decreased to improve perfomance. Simple Example

bp_hit_ratio =  (1 - ( (bp data phys rd + bp inx phys rd) / (bp data
logic rd + pool index logical rd) ))
print bp_hit_ratio
if (bp_hit_ratio < 0.9)
   print Low bp_hit_ratio. Concider increasing bufferpool size

For NUM_IOCLEANERS I have only seen rather vauge statements such as:

Increase NUM_IOCLEANERS if "Buffer pool data writes" is much bigger
than "Asynchronous pool data page writes." or if "Dirty page steal
cleaner triggers" / "Dirty page steal cleaner triggers + ..." is too
high.

I understand that it is impossible to exactly define "much bigger" or
"too high" but as a rule of thumb, when would you concider increasing
NUM_IOCLEANERS regarding "Buffer pool data writes" vs "Dirty page steal
cleaner triggers", 2 times,5 time,10 times,100 times or something
completely different. And the same goes for ratio between Dirty page
steal cleaners and Dirty page steal cleaners + Dirty page threshold
cleaner triggers + LSN Gap cleaner triggers.

Thanx in advance
/Lennart