sp_sysmon can give you information about Adaptive Server system behavior before and after tuning. Study the entire report to understand the full impact of the changes you make. Sometimes removing one performance bottleneck reveals another. Similarly, tuning efforts might improve performance in one area while actually causing performance degradation in another area.
In addition to pointing out areas for tuning work, sp_sysmon output is valuable in determining when further tuning will not pay off in additional performance gains. It is just as important to know when to stop tuning Adaptive Server, or when the problem resides elsewhere, as it is to know what to tune.
A single sp_sysmon run presents resource utilization during the specific time interval. Make sure that the time intervals you use clearly represent the workload and situation for which you are tuning Adaptive Server.
Other information can contribute to interpreting sp_sysmon output:
Information on the configuration parameters in use, from sp_configure or the configuration file
Information on the cache configuration and cache bindings, from sp_cacheconfig and sp_helpcache
Information on disk devices, segments, and the objects stored on them
