TRANSFORMATION OF UML DESIGN MODEL INTO
PERFORMANCE MODEL
A Model-Driven Framework
Ramrao Wagh, Umesh Bellur, Bernard Menezes
Indian Institute of Technology, Bombay, Powai, Mumbai, India
Keywords: Software Performance, Model Transformation, UML, MDA.
Abstract: Software Performance Engineering is receiving increasing attention in today’s software dominated world.
Compared to research work in performance evaluation in hardware and networks, this field is still in its
nascent stage. Many methods have been proposed but majority of them are unable to adapt in the software
development life-cycle dominated by professionals without substantial performance engineering
background. We propose UPE - a Model Driven Software Performance Engineering Framework to facilitate
performance engineering within software development life cycle, based on OMG’s MDA initiative.
1 INTRODUCTION
For a large and complex software systems such as
Enterprise systems designed using distributed
technology, it is of paramount importance that the
stakeholders are satisfied that the proposed system
will meet necessary functional as well as non
functional requirements. As development of such
systems is costly it is necessary to get a realistic
estimate of the level of quality requirements likely to
be achieved, before the resources are committed for
the project. The best possible time to make reliable
estimates that are dependable, especially for
performance, is at architectural design stage since
performance in terms of response time of software,
throughput and device utilization is dependent on the
behavioral as well as structural aspects of the
software design model.
Since UML(Infra, 2003)(Super, 2003) is being
increasingly used to express design, our overall
research work is aimed at devising performance
analysis methods applicable to software design
models expressed using UML artifacts.
This paper is structured as follows. In section 2
we look at the related work and the limitations of
this work; Section 3 then presents our solution
framework UPE that is based on MDA, section 5
will present the conclusion.
2 RELATED WORK
Over the last decade there has been a steady rise in
the number of performance prediction methods for
software systems at design stage (WOSP,98-05).
Majority of these methods follow an approach where
a performance model is constructed for the target
software and later evaluated. All these methods are
broadly based on at least one of the following
performance models: Queuing Network Model, Petri
Nets, Process Algebra, Markov Chains, Simulation
(Balsamo,2004). One of the major drawbacks of
majority of these methods is that one has to
manually construct the performance model by
studying the software system. As average software
developer is not conversant with performance
modeling, a specialist may be needed to carry out
the performance modeling.
Although number of UML based methods have
been proposed for the performance estimation from
software design (Balsamo, 2004), they still suffer
from the following major drawbacks in general:
Restricted to use of particular set of UML
diagrams
There is no proper way of specifying
performance parameters
No provision to represent the performance results
back into the model
Transformation methods are not based on
standards
They are tailored towards use of specific, often
proprietary performance analysis tools
576
Wagh R., Bellur U. and Menezes B. (2006).
TRANSFORMATION OF UML DESIGN MODEL INTO PERFORMANCE MODEL - A Model-Driven Framework.
In Proceedings of the Eighth International Conference on Enterprise Information Systems - ISAS, pages 576-579
DOI: 10.5220/0002469605760579
Copyright
c
SciTePress
Make use of UML designs that are stored in
lengthy and verbose XML form.
We will briefly mention three recent important
methods.
The Core Scenario Model (CSM) (Petriu, 2004)
extracts the relevant performance information
scattered implicitly and explicitly around various
UML diagrams into a single CSM which will then
facilitate the conversion into any desired
performance model that can be executed by
performance tools. Two transformations are required
i.e. from UML model to CSM (U2C) and from CSM
to Performance model (C2P). Authors propose to
use QVT(QVT, 2003) for these transformations but
due to non-availability of tools are currently using
XSLT based transformations.
(Skene, 2003) apply the Model driven
performance analysis to a distributed middleware
based enterprise application developed using EJBs.
They use MDA supported lightweight extension
mechanism using different UML profiles and
merging them to represent the design model.
Specifically UML profile for SPT and EJB are
merged to define a joint profile. A simple profile to
represent queuing network model is specified as
Analysis profile. Lack of tool support has been cited
as the reason for not automating the transformations
defined.
(D’Ambrogio, 2005) proposes a comprehensive
framework for achieving interoperability amongst
various tools based on MDA approach. Considering
the lack and shortcomings of existing tools and
specifications, they prescribe a three layer approach
comprising of a technology independent
metamodeling layer (MML), technology specific
model implementation layer (MIL) and tool layer
(TL) to exploit use of available technologies and
tools built on MDA and XML. Due to lack of proper
tool support for implementing QVT transformations,
XML based technologies such as XSLT/XQuery is
used for transformation.
Many of the drawbacks mentioned earlier are
still retained in these three representative methods.
More specifically, Out of these three methods, the
one proposed by D’Ambrogio looks most promising
as a complete but complex framework is defined by
them to achieve transformation by using proposed
standards as well as combining it with existing
technologies. However, their target performance
model is not generic. On the other hand the idea of
representing an intermediate performance model in
CSM is also promising as it combines all the
performance related information in one place before
a complex transformation is applied. Approach by
Skene is more tied to a particular platform, i.e, EJB,
but could be applied to any other problem domain by
merging suitable domain information.
3 UNIFIED PERFORMANCE
ENGINEERING FRAMEWORK
We propose a Model Driven Framework based on
various MDA(MDA, 2003) standards. Figure 1
depicts the overall UPE framework. All the
metamodel as well as transformations are based on
MOF(MOF, 2003). We claim that basing the design
model as well as analysis models on same
metamodel i.e. MOF will facilitate easy
transformation.
The main advantage of this approach is that
performance estimation can be done continuously
during the design stage. It will also maintain the
performance parameters separate from the design
model so as not to clutter the design model during
development. Another advantage will be that
transformation will be based on metamodel level
that will be expressed in a high-level model
transformation language compared to complex XML
based transformations.
We present the UPE approach in more details in
the following sub-sections by describing the various
models and the required transformations:
3.1 Design Model
As design evolves during the development process,
any of the UML features deemed fit by the
developers are to be used. Organizations usually
follow some process standards such as Unified
process, which prescribe the set of diagrams to be
used at different stages. However, in the initial stage,
we will focus on Use case diagram to represent the
workload, activity diagram to represent the
scenarios, and deployment diagram to represent the
resource allocations. In particular we will be using
UML 2.0 notations and diagrams as well as any
PSM specific profiles such as CORBA or J2EE.
3.2 Performance View
We propose a novel idea of defining performance
views to represent performance related input as well
as results based on the concept described in MOF
QVT (QVTP, 2003). This mechanism will allow any
other view, say, security model, to be described
without interfering with performance model on the
same design model. This will be an editable view
that will allow the selected UML diagrams from the
design model to be annotated with performance data
TRANSFORMATION OF UML DESIGN MODEL INTO PERFORMANCE MODEL - A Model-Driven Framework
577
by using an extension of UML profile for SPT(SPT,
2001).
3.3 Intermediate Performance
Model
From this performance view, the intermediate
performance model that combines performance
related information from all the design artifacts and
performance view is generated. This will involve a
transformation that will create the Intermediate
Performance model by systematically analyzing
each of the activity diagrams and combining their
information into one performance model. The IPM
metamodel is closely related to CSM approach of
(Petriu, 2004).
3.4 Performance Analysis Model
The transformation of this IPM will result in the
performance model of choice such as Queuing
Network Model, SPA, Stochastic Petri Nets, etc.
These different transformations need to be designed
to achieve the desired performance model. This
model then will generate the parameters that will be
submitted to the Performance tool for solving the
model.
3.5 Transformations
Various model transformations will be needed for
converting Design Model annotated with
performance into Intermediate Performance model
and for transforming Intermediate performance
Model into Performance Analysis Model.
An editable view generation is required for
performance annotations to be specified on the
software design model.
3.6 Feedback
The results from the performance tools will be sent
back and represented in the performance view. This
will also need similar reverse transformations which
we are not currently focusing upon.
As QVT based approach will lead to
standardization in the model transformation field, we
are planning to use one of the suggested approaches
for our research work. We will be using OCL 2.0
(OCL, 2003) , MTL from QVT Partners (Biju, 2003)
that is based on the relational approach (Akehurst,
2003) Although some of the required specification
standards are not completed by the standards body,
we will apply the concepts, not from the point of
view of complying with the standards but in a way
to validate them for a specific domain such as
Design Model
(UCD, AD,
Performance
View
Intermediate
Performance
Model
MOF
UML
metamodel
Perf View
metamodel
IPM
Metamodel
Performance
Metamodel
Performance
Model
V
T
T
V
T
InstanceOf
View
Transformation
Figure 1: Unified Performance Engineering Framework.
ICEIS 2006 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
578
performance. We are hopeful that this may
contribute to the field of model driven development
by identifying shortcomings and proposing
alternative solutions.
4 CONCLUSIONS
We have outlined UPE - a framework for model
driven software performance engineering in this
paper. The need for such an approach was
established; the relevant standards and technologies
that are under various stages of completion
themselves were described. Since the underlying
field of MDD itself is in a high state of flux, it is a
challenge to devise an approach that will be adaptive
to such changing scenario.
As model driven paradigm is increasingly being
embraced by researchers and industry, We are
hopeful that we can contribute to this pool of
knowledge by applying this approach to the domain
of Software Performance Engineering thereby
validating the same and making performance
analysis an integral part of the software development
activity.
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