WIESS 2000 Abstract
Meeting Performance Goals with the HP-UX Workload Manager
Indira Subramanian, Cliff McCarthy, and Michael Murphy, Hewlett-Packard Co.
The HP-UX Workload Manager helps workloads meet
user-specified performance goals by dynamically adjusting
their access to resources such as CPU. We implemented this
workload manager as a part of a feedback control system,
using existing resource control and performance instrumentation
Successful consolidation of multiple workloads on to a
single server demands that users be guaranteed consistent
levels of workload performance. Users should be able to
define Service Level Objectives (SLO), specifying the performance
goals they seek and their relative importance. To
achieve target performance consistently, applications' access
to resources such as CPU and memory must be adjusted automatically.
Workload managers can be classified in to two categories.
An entitlement-based manager allocates resources based on
a specification of resource entitlements. Goal-based workload
managers adjust the resources allocated to a workload,
based on a specification of performance goals.
Entitlement-based and goal-based workload managers
have been supported in some commercial and experimental
systems. Several UNIX OS vendors implement entitlement-based
resource managers, which do not use any feed-back
mechanism to meet performance goals. IBM's OS/390
goal-based workload manager (WLM) employs extensive instrumentation
to gather detailed information about an appli-cation's
resource needs, and adjusts resource allocations.
Adjusting the use of system resources to meet response
time goals has been in wide use in Transaction Processing
(TP). Several experimental transaction processing sys-tems
have exploited feedback mechanisms to meet response
The HP-UX Workload Manager is distinct from the sys-tems
discussed above that also use feedback control to adjust
resources. First, the workload manager does not monitor
workload performance directly. Instead, it receives a work-load's
performance data through an API from a performance
monitor created by the application provider (or system administrator).
Second, the workload manager uses a simple
proportional controller to determine the resources that must
be allocated to a workload. Third, the workload manager has
been designed to take advantage of the existing infrastructure
of tools that includes Process Resource Manager (PRM),
and the Event Monitoring Service (EMS, which raises an
alarm when a performance goal is not being met). Fourth,
unlike TP monitors, which handle workload management
exclusively for transaction processing systems, the HP-UX
Workload Manager can handle a wide variety of application