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Local State Space Construction for Compositional Verification of Concurrent Systems Hao Zheng Department of Computer Science and Engineering University of South Florida H. Zheng (CSE USF) Local State Space Construction for Compositional

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Local State Space Construction for Compositional Verification of Concurrent Systems

Hao Zheng

Department of Computer Science and Engineering University of South Florida

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 1 / 19

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Introduction

  • Scope: model checking of finite state concurrent systems.
  • Asynchronous.
  • Communication via shared variables.
  • Applications: communication protocols, multi-thread programs,
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 2 / 19

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Introduction

  • Scope: model checking of finite state concurrent systems.
  • Asynchronous.
  • Communication via shared variables.
  • Applications: communication protocols, multi-thread programs,
  • To present a local state space construction approach.
  • As a key part of a methodology for scalable model checking of

finite state concurrent systems.

  • To addressing state explosion due to the interleavings of

concurrent executions.

  • For local safety verification.
  • To helping partial order reduction to be more effective in global

state space.

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 2 / 19

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Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 6

Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state transition models G1, . . . , Gn

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 7

Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state transition models G1, . . . , Gn Is ϕ verified?

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 8

Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state transition models G1, . . . , Gn Is ϕ verified? Terminate Yes

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 9

Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state transition models G1, . . . , Gn Is ϕ verified? Terminate Yes Behavioral Analysis Transition Dependence Relation Global State Space Search with Partial Order Reduction No

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 10

Overview of the Methodology

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state transition models G1, . . . , Gn Is ϕ verified? Terminate Yes Behavioral Analysis Transition Dependence Relation Global State Space Search with Partial Order Reduction No

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 3 / 19

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SLIDE 11

Outline

  • Background
  • Local state space construction: previous work
  • The thread-modular approach
  • Local state space construction: an improvement
  • Synchronized local state space search
  • Experimental results
  • Discussions and conclusions
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 4 / 19

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SLIDE 12

Background

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 5 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0)

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0) Processes

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0) Variable declarations

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0) Local initial states

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0) Action sets

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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High Level Description: A Simple Example

M1 = (V1, q0, A1); V1 = {l1, x, z}; q0 = (l1 = 0, x = 0, z = 0); A1 = {α1, α2, α3, α4}; where α1 = (l1 = 0 ∧ x > 0, z := x + 1; l1 := 1); α2 = (l1 = 1, x := 0; l1 := 2); α3 = (l1 = 2 ∧ x > 0, z := z ∗ x; l1 := 3); α4 = (l1 = 3, x := 0; z := 0; l1 := 0); M2 = (V2, p0, A2); V2 = {l2, x, y}; p0 = (l2 = 0, x = 0, y = 0); A2 = {β1, β2}; where β1 = (l2 = 0 ∧ y = 0, x := 2; l2 := 1); β2 = (l2 = 1 ∧ x = 0, y := 1; l2 := 0) M3 = (V3, s0, A3); V3 = {l3, x, y}; s0 = (l3 = 0, x = 0, y = 0); A3 = {γ1, γ2}; where γ1 = (l3 = 0 ∧ y = 1, x := 3; l3 := 1); γ2 = (l3 = 1 ∧ x = 0, y := 0; l3 := 0) Guard Assignments

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 6 / 19

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State Graphs

q0 q1 q2 q3 q4 q5 p0 p1 p2 p3 s0 s1 s2 s3 s4 s5 p4 p5

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 7 / 19

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State Graphs

q0 q1 q2 q3 q4 q5 p0 p1 p2 p3 s0 s1 s2 s3 s4 s5 p4 p5

States labeled w.variable assignments

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 7 / 19

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State Graphs

q0 q1 q2 q3 q4 q5 p0 p1 p2 p3 s0 s1 s2 s3 s4 s5 p4 p5

Local transitions

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 7 / 19

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State Graphs

q0 q1 q2 q3 q4 q5 p0 p1 p2 p3 s0 s1 s2 s3 s4 s5 p4 p5

External transitions

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 7 / 19

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Local State Graph Construction

The Thread Modular Model Checking Approach

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state graphs G1, . . . , Gn

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 8 / 19

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Thread Modular Model Checking (TMMC)

  • Each process is verified locally with a derived environment

capturing all possible interactions with its neighbors.

  • For each process, its environment is derived from the guarantees
  • f its neighbors.
  • The guarantee of a process P is a set of state transitions on the

shared variables resulting from executions of process P.

∀ Process Pi, fix its env. Ei = ∅ ∀ Process Pi, compute its guarantee gi wrt Ei ∃gi st gi is extended? ∀ Process Pi, update its env. Ei = ∪i=jgj Terminate. No Yes

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 9 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 0, 0 0, 0, 0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 0, 0 1, 2, 0

β1

0, 0, 0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 2, 0

β1

0, 0, 0 1, 2, 0

β1

0, 0, 0 0, 2, 0

β1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 2, 0

β1

1, 2, 3 2, 0, 3

α1 α2

0, 0, 0 1, 2, 0

β1

0, 0, 0 0, 2, 0

β1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 2, 0

β1

1, 2, 3 2, 0, 3

α1 α2

0, 0, 0 1, 2, 0

β1

1, 0, 0

α2

0, 0, 0 0, 2, 0

β1

0, 0, 0

α2

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Illustration

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 2, 0

β1

1, 2, 3 2, 0, 3

α1 α2

2, 3, 3 2, 2, 3 3, 3, 9 0, 3, 0 1, 3, 4 2, 0, 4

β1 γ1 α3 γ1 α1 α2

0, 0, 0 1, 2, 0

β1

1, 0, 0

α2

0, 0, 1

β2

0, 3, 1

γ1

0, 0, 0 0, 2, 0

β1

0, 0, 0

α2

0, 0, 1

β2

1, 3, 1

γ1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 10 / 19

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TMMC: Weakness

G1 [l1, x, z] G2 [l2, x, y] G3 [l3, x, y]

0, 0, 0 0, 2, 0

β1

1, 2, 3 2, 0, 3

α1 α2

2, 3, 3 2, 2, 3 3, 3, 9 0, 3, 0 1, 3, 4 2, 0, 4

β

1

γ1 α3 γ1 α1 α2

0, 0, 0 1, 2, 0

β1

1, 0, 0

α2

0, 0, 1

β2

0, 3, 1

γ1

0, 0, 0 0, 2, 0

β1

0, 0, 0

α2

0, 0, 1

β2

1, 3, 1

γ1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 11 / 19

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Improved Local State Graph Construction

The Synchronized Local State Space Search Approach

Parallel composition of communicating processes M1 . . . Mn | = ϕ Local State Space Construction & Verification Local state graphs G1, . . . , Gn

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 12 / 19

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Local State Space Search (LS3)

  • Construct local state graphs by searching joint state space of

communicating processes.

  • Extend the local SGs resulting from interactions among processes.
  • Avoiding adding external transitions in wrong states.

Algorithm

∀ Process Pi, initialize Gi with initi ∀ Processes Pi and Pj, search their joint state space Gij Extend Gi and Gj wrt Gij ∃ Process Pi st Gi extended with new transitions? Terminate. No Yes

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 13 / 19

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SLIDE 34

LS3: Illustration

localSearch() G1 G2 G3

M1, M2 q0 p0 s0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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LS3: Illustration

localSearch() G1 G2 G3

M1, M2 q0, p0 q1, p1 q2, p1 q3, p2 q3, p3 β1 α1 α2 β2 q0 p0 s0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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LS3: Illustration

localSearch() G1 G2 G3

M1, M2 q0, p0 q1, p1 q2, p1 q3, p2 q3, p3 β1 α1 α2 β2 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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LS3: Illustration

localSearch() G1 G2 G3

M2, M3 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 38

LS3: Illustration

localSearch() G1 G2 G3

M2, M3 p0, s0 p1, s1 β1 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 39

LS3: Illustration

localSearch() G1 G2 G3

M2, M3 p0, s0 p1, s1 β1 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0 s1 β1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 40

LS3: Illustration

localSearch() G1 G2 G3

M1, M3 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0 s1 β1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 41

LS3: Illustration

localSearch() G1 G2 G3

M1, M3 q0, s0 q1, s1 q2, s1 q3, s2 β1 α1 α2 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0 s1 β1

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 42

LS3: Illustration

localSearch() G1 G2 G3

M1, M3 q0, s0 q1, s1 q2, s1 q3, s2 β1 α1 α2 q0 q1 q2 q3 β1 α1 α2 p0 p1 p2 p3 β1 α2 β2 s0 s1 β1 s2 α2

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 14 / 19

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SLIDE 43

LS3: Illustration: Final Results

G1 G2 G3

q0 q1 q2 q3 q4 q5 β1 α1 α2 γ1 α3 α4 q0 p1 p2 p3 p4 p5 β1 α2 β2 γ1 α4 γ2 s0 s1 s2 s3 s4 s5 β1 α2 β2 γ1 α4 γ2

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 15 / 19

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SLIDE 44

Experiment 1

  • Experimented on small examples to show that LS3 is capable of

avoiding extra states added into local SGs.

phil peterson.3 syzmanski.4 Mono (9, 9, 9, 9) (2627, 2421, 2745) (4311, 4415, 4383, 4352) TMMC (16, 16, 16, 16) (2997, 2952, 2952) (5875, 6125, 6250, 6375) LS3 (9, 9, 9, 9) (2627, 2421, 2745) (5201, 5453, 5598, 5755)

Mono: construct local SGs while searching the global state space of the whole system.

  • A special case of LS3 applied to all processes.
  • Used as the baseline to compare the results from TMMC and LS3.
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 16 / 19

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SLIDE 45

Experiment 1

  • Experimented on small examples to show that LS3 is capable of

avoiding extra states added into local SGs.

phil peterson.3 syzmanski.4 Mono (9, 9, 9, 9) (2627, 2421, 2745) (4311, 4415, 4383, 4352) TMMC (16, 16, 16, 16) (2997, 2952, 2952) (5875, 6125, 6250, 6375) LS3 (9, 9, 9, 9) (2627, 2421, 2745) (5201, 5453, 5598, 5755)

Mono: construct local SGs while searching the global state space of the whole system.

  • A special case of LS3 applied to all processes.
  • Used as the baseline to compare the results from TMMC and LS3.
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 16 / 19

slide-46
SLIDE 46

Experiment 1

  • Experimented on small examples to show that LS3 is capable of

avoiding extra states added into local SGs.

phil peterson.3 syzmanski.4 Mono (9, 9, 9, 9) (2627, 2421, 2745) (4311, 4415, 4383, 4352) TMMC (16, 16, 16, 16) (2997, 2952, 2952) (5875, 6125, 6250, 6375) LS3 (9, 9, 9, 9) (2627, 2421, 2745) (5201, 5453, 5598, 5755)

Mono: construct local SGs while searching the global state space of the whole system.

  • A special case of LS3 applied to all processes.
  • Used as the baseline to compare the results from TMMC and LS3.
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 16 / 19

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SLIDE 47

Experiment 2

Method Time Mem State counts of local state graphs brp TMMC 2.7 174 (5600∗, 2226∗, 351694∗, 295∗, 84, 30) LS3 9.8 214 (1368, 1496, 25091, 77, 35, 14) iprotocol TMMC 8.8 408 (19, 1256∗, 53, 18104∗, 110627∗, 283444∗) LS3 10.1 68 (19, 230, 29, 2647, 3656, 23747) lamport TMMC 15.9 106 (9344∗, 9344∗, 9344∗, 9344∗, 9344∗) LS3 24.8 143 (8800, 8800, 8800, 8800, 8800) lann TMMC 1.3 15 (250, 250, 250, 250, 566, 560, 561, 412) LS3 4.3 33 (250, 248, 248, 248, 566, 554, 555, 408) peterson.4 TMMC TO − (124535∗, 104922∗, 104088∗, 103319∗) LS3 10.9 88.5 (13573, 12993, 12869, 12801) syzmanski.5 TMMC 59.4 198 (35000∗, 36250∗, 36875∗, 37500∗, 38125∗) LS3 59.1 211 (30684∗, 31934∗, 32659∗, 33444∗, 34265∗)

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 17 / 19

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SLIDE 48

Discussions & Conclusions

  • Presented an improved local state space construction method

LS3.

  • A key part of a methodology to address the state explosion

problem due to interleavings of concurrent executions.

  • LS3 can produce local SGs with less unreachable states.
  • LS3 may incur noticeable time/mem. overhead.
  • Need to balance between size & accuracy of local SGs and cost of

time & memory.

  • Good target applications are loosely coupled systems.
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 18 / 19

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SLIDE 49

Discussions & Conclusions

  • Presented an improved local state space construction method

LS3.

  • A key part of a methodology to address the state explosion

problem due to interleavings of concurrent executions.

  • LS3 can produce local SGs with less unreachable states.
  • LS3 may incur noticeable time/mem. overhead.
  • Need to balance between size & accuracy of local SGs and cost of

time & memory.

  • Good target applications are loosely coupled systems.
  • Future work:
  • Improve the LS3 method further.
  • Combine TMMC and LS3 for their advantages.
  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 18 / 19

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SLIDE 50

Thank you

and

Questions?

  • H. Zheng (CSE USF)

Local State Space Construction for Compositional Verification of Concurrent Systems 19 / 19