For performance purposes, OS monitoring should include all of the following except:

The selection of print spooling as an element that typically does not require constant monitoring for performance purposes is based on the relative impact it has on overall system performance compared to other metrics. Print spooling involves temporarily storing print jobs in memory until they can be printed, and while it is necessary to ensure that printing tasks are managed effectively, it usually does not contribute significantly to the performance bottlenecks of an operating system.

In contrast, monitoring disk space, disk I/O usage, and CPU usage is crucial for maintaining system performance. Disk space is pivotal since running out of storage can lead to system failures. Disk I/O usage provides insights into how efficiently data is being read from and written to disk, which directly affects application performance. CPU usage is critical as it helps assess whether the processor is being over or under-utilized, ensuring that the system is operating efficiently without bottlenecks.

Thus, while print spooling is important for print management, its performance implications are generally less critical than those of the other options listed, making it the least essential focus for OS performance monitoring.