The unpredictable factors are:

  1. 21 different CPUs (and even those 21 CPUs are constantly changing based on BP voting)
  2. Potentially different max-transaction-time for each BP (can a dApp developer even see these values for each BP?)
  3. Virtual memory will drastically slowdown transactions in an unpredictable way

How do dApp developers manage max-transaction-time with all these unpredictable factors?

1 Answer 1


dApp developers don't really need to manage max-transaction-time. This is not the way to plan your dApp.

Your share of CPU is determined by your share of the EOS tokens you delegate towards CPU as a percent of total CPU.

In case of over capacity, you will enjoy additional CPU processing power.

Regarding the unpredictable factors:

  1. 21 different CPUs, they take turns processing transactions in a round robin method so you can take the average of the 21 top BPs. Yes this list is dynamic and changes with votes changing. You can Add some of the top stand by block producers, perhaps this will improve the estimate. Also, consider that Block Producers will upgrade their hardware and the EOSIO software will also be improved. There are even plans to create custom CPUs with optimizations for EOSIO.

  2. max-transaction-time can be tweaked by each block producer. There are reasonable default values for all parameters and you can assume that most will just settle with those. A block producer that changes this too much risks dropping transactions that other block producers will be able to process. This will make it a lower quality block producer and voting will be reduced for it.

  3. No virtual memory is allowed. This is why RAM is such an interesting topic for debate.

  • Thank you again (you answered my other question too haha). Follow up questions: do you know the reasonable default values for max-transaction-time (I keep hearing 150ms) and/or a way to see the configs for each BP? And regarding virtual memory: so Dan talking about virtual memory was about research for the future?
    – PunchPlump
    Jul 19, 2018 at 18:13
  • Future research, yes. More data from the field will help fine tune this. I don't know how to get the config of a specific bp.
    – Ami Heines
    Jul 19, 2018 at 18:25

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