Abstract: According to an example aspect of the present invention, there is provided apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to store group definition information, receive plural reports from a set of distributed-computing entities each report comprising performance information and a transaction identifier, form a group of at least a proper subset of the plural reports based on their respective transaction identifiers and the group definition information, and obtain an aggregate performance report using both the performance information in each one of the reports in the group, and a performance metric of the group.