Provided are a computer program product, system, and method for determining when to send message to a computing node to process items using a machine learning module. A send message threshold indicates a send message parameter value for a send message parameter indicating when to send a message to the computing node with at least one requested item to process. Information related to sending of messages to the computing node to process requested items is provided to a machine learning module to produce a new send message parameter value for the send message parameter indicating when to send the message, which is set to the send message parameter value. A message is sent to the computing node to process at least one item in response to the current value satisfying the condition with respect to the send message parameter value.