1. A method comprising: detecting, by one or more computer processors, a timed-out input/output (I/O) operation; identifying, by the one or more computer processors, each hardware component of a plurality of hardware components involved with the timed-out I/O operation, wherein the hardware components include a plurality of types of hardware components; increasing, by the one or more computer processors, involve counts of each of the identified hardware components; identifying, by one or more computer processors, a plurality of suspicious hardware components based, at least in part, on a hardware hierarchy including one or more of the types of hardware components, wherein: the hardware hierarchy specifies a ranking of suspicious hardware components of different types of hardware components based, at least in part, on subsequently identified timed-out I/O operations; each type of hardware component represents a respective hierarchical level of the hardware hierarchy based, at least in part, on how delays in receipt of instructions are propagated between the plurality of types of hardware components, each hierarchical level of the hardware hierarchy includes no more than one suspicious hardware component, and a suspicious component is a hardware component having a highest involve count within the respective hierarchical level of the hardware hierarchy; and identifying, by the one or more computer processors, a performance-degrading hardware component from among the plurality of suspicious hardware components based, at least in part, on the involve counts and the hardware hierarchy, wherein the performance-degrading hardware component is in a layer of the hardware hierarchy that is lower than all other layers that include suspicious hardware components.