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Roadmap
Performance
modeling
evaluationGeneralized
Stochastic Petri Nets (GSPNs)
Symbolic Hierarchical Automated Reliability and
Performance Evaluator (SHARPE)
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Software Performance
Software developers’ world (vocabulary) is intrinsically distant from performance analysts’ one.
APPLICATIONMODEL
APPLICATIONPERFORMANCE
MODEL
APPLICATIONPERFORMANCE
MODEL
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Performance Notations
Markov process
es
Queueing
Networks
Generalized
Stochastic Petri Nets Stochast
ic Process Algebras
Simulation
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Performance Model Elements : GSPNs
ARC WEIGHTS
Graphical Notation
PLACES
MARKING
X
Px
FLOW
RELATION
TRANSITIONS
Symbols Description
The number of tokens in places defines the marking of the net at a certain time
Arc weights are numbers associated to arcs
The arcs are input, output, or inhibitor and represent the link between places and transitions
Transitions are immediate or timed and represent the system changing state
Places are locations that represent (possibly partial) states of a system
timm ttimed
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GSPNs formal definition
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1
S = ( P , T , I , O , H , M0 )
P1
PLACES INITIAL
MARKING
INPUTTRANSITIONS
(immediate
P2
P3
2
P4
4
t1 t2
or timed)
OUTPUT
INHIBITION
2
PN system
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GSPNs incrementally
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1
P1
P2
P3
t12
2
1
P1
P2
P3
t1
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1
P1
P2
P3
t1
2
t2
3
Petri Net
Stochastic Petri Net
Generalized Stochastic Petri Net
P4
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GSPNs more formal
P is set of placesT is set of transitions, T ∩ P = Ø
I, O, H : T -> Bag(P) with Bag(P) multiset on P
Mo : P ->
t = { p E I (t,p) > 0 } input arcs t = { p E O (t,p) > 0 } output arcs °t = { p E H (t,p) > 0 } inhibitor arcs