Abstract: Performance of a collection of machines, arranged in a linear sequence of machines that form a linear communication orbit (LCO), is monitored. Multiple machines in the LCO receive, via the LCO, a set of rules (or various subsets of the same set of rules), each rule specifying one or a combination of conditions (e.g., a performance metric and corresponding criterion) for satisfying the rule, evaluate those rules with respect to locally occurring events and local processes, and store results of those evaluations in a local database. In response to a query sent to the machines via the LCO, each of the machines returns a report, including information identifying processes whose performance during the specified time period satisfies at least one rule in the set of one or more rules. Those reports are aggregated and used to generate a merged report reflecting performance information with respect to a set of machines.