Block cache might be too small

What I want to do

I need to configure Block cache in the latest Dgraph .
Can you please explain what are the 3 parameters in the percentage option ?

What I did

I have started the alpha with below commands
op1 : nohup dgraph alpha --my= --zero= --cache size-mb=1024 --cache percentage=50,30,20 --security whitelist= &

op 2 :

nohup dgraph alpha --my= --zero= --cache size-mb=1024 --cache percentage=0,70,30 --security whitelist= &

Dgraph metadata

Dgraph version : v21.03.2
Dgraph codename : rocket-2
Dgraph SHA-256 : 00a53ef6d874e376d5a53740341be9b822ef1721a4980e6e2fcb60986b3abfbf
Commit SHA-1 : b17395d33
Commit timestamp : 2021-08-26 01:11:38 -0700
Branch : HEAD
Go version : go1.16.2
jemalloc enabled : true

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