Bottleneck analysis is a performance monitoring technique that identifies execution states of a workload and the frequency of each state. When the results of this analysis are averaged over time, it is possible to find which states (such as waiting for CPU) prevent the workload from achieving its service goal. Identification and easing of bottlenecks is a key part of performance management.
This workspace displays resource contention information for the address space you selected from the Address Space CPU Utilization Summary table in the Address Space Overview workspace. It shows which workloads are using the resources that the impacted workload needs, which allows you to determine how various workloads are interfering with each other. This helps you to reduce degradation of the monitored workloads.
At the top of the workspace is the Execution States table, which provides a snapshot of any non-zero execution states that this particular job or address space is in for this period. This table contains three columns: Attribute, Percent, and Resource. Each attribute listed under the Attribute heading is one whose percentage value is greater than 0.0 in the Address Space Bottlenecks Detail workspace. The Percent column shows the percentage of time associated with an attribute for the specific address space in question. The Resource column only applies to enqueues and I/O waits. For an I/O Wait, it lists the device type, the volume serial number, and the device address. For an enqueue, it lists the enqueue major name.
The Active I/O Wait row contains a link to the DASD MVS Devices workspace. The Enqueue Wait attribute row contains a link to the Enqueue and Reserve Summary workspace.
The workspace also contains an Impactors for Job Name bar chart, which shows which address spaces are impacting the favored address space, how they are impacting it, and to what extent they are impacting it.
The Address Space Bottlenecks Detail - Contention (%) by Resource table
shows detailed information about the waits the address space is experiencing
for various resources. By default, the Tape Mount column has a preset
threshold (GT 0.0) that provides an informational alert
when the job is being delayed for a tape mount.
The Impact Analysis for Job Name table view provides the same information as the Impactors for Job Name bar chart, along with the Job Name, address space ID, and the percentage of the total delay for which each impactor is responsible.
You can link to this workspace from the Address Space Overview workspace.
See also:
Address Space Overview Workspace
Organization of
system-level predefined workspaces
Attribute groups used by system-level predefined workspaces