How can I know the cpu and net bandwidth required for my transaction to be completed?

Question

Before pushing an action on blockchain, how do I find out the minimum amount of cpu and net bandwidth required for my transaction to be completed? If there is no way to know such thing, then how do I decide how much EOS do I delegate to my account (I want to minimise the amount of EOS delegated)

Answer 1

CPU bandwidth depends on execution time and net bandwidth depends on the transaction size (bytes). The only way to know is to measure, either on the mainnet or on a similarly-loaded testnet. CPU bandwidth will vary between producers.

Option A:

• Run cleos get account and look at the used fields under net bandwidth and cpu bandwidth
• Issue the transaction
• Run cleos get account and subtract the fields

Option B:

• Issue the transaction
• Get these fields from the transaction from the block: cpu_usage_us and net_usage_words

cleos get account example:

$ cleos get account useraaaaaaaa

net bandwidth: (averaged over 3 days)
     staked:   50335451.0469 SYS           (total stake delegated from account to self)
     delegated:       0.0000 SYS           (total staked delegated to account from others)
     used:               384 bytes
     available:        38.46 Gb   
     limit:            38.46 Gb   

cpu bandwidth: (averaged over 3 days)
     staked:   50335451.0469 SYS           (total stake delegated from account to self)
     delegated:       0.0000 SYS           (total staked delegated to account from others)
     used:             17.05 ms   
     available:        0.676 hr   
     limit:            0.676 hr