Starting conditions for post-mortem debugging using deterministic replay of real-time systems

Huselius, Joel; Sundmark, Daniel; Thane, Henrik

doi:10.1109/emrts.2003.1212741

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…The approach targets real-time systems but the authors omit to show how to cope with real-time constraints when recording internal data variables. Other approaches exist, e.g., [5], [10], and [19]. However, they are all associated with substantial overhead for checkpointing and are in no way real-time capable.…”

Section: Obtaining Starting Conditionsmentioning

confidence: 96%

A Comprehensive Solution for Deterministic Replay Debugging of SoftPLC Applications

Prähofer

Schatz

Wirth

et al. 2011

IEEE Trans. Ind. Inf.

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Deterministic replay debugging is an approach to finding bugs in deployed software. It records an application run in the field so that it can deterministically be replayed offline in a development system for debugging purposes. To enable deterministic replay debugging, it is necessary to record all external influences and sources of nondeterminism in the original program run. From that trace log and from a known initial state, the program can be replayed deterministically without requiring any connection to the original environment.In this paper, we present a solution for deterministic replay debugging of hard real-time multitasking SoftPLC applications written in the IEC 61131-3 languages. By taking advantage of the special properties of these programs and by careful engineering, our technique allows recording a SoftPLC application run in the field with minimal overhead and obeying real-time constraints. In later phases, which are offline, the original program run is reconstructed from the minimal information recorded so it can be replayed for debugging. In comparison to previous work, our solution has several advantages: Instead of recording task scheduling information, it reconstructs the task interleaving based on data dependencies, thereby significantly simplifying the recording phase. Additionally, it incorporates a technique for periodically capturing the complete internal state of the system, which can later be used as a starting point for replay.We present the conceptual basis of our approach, a tool chain which provides deterministic replay debugging to the user as a set of fully automated tools, and an evaluation as well as an industrial case study for validating the approach.

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Section: Obtaining Starting Conditionsmentioning

confidence: 96%

A Comprehensive Solution for Deterministic Replay Debugging of SoftPLC Applications

Prähofer

Schatz

Wirth

et al. 2011

IEEE Trans. Ind. Inf.

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show abstract

“…After a system crash, the execution recording is collected, e.g., by means of exception or error handlers, and analyzed (I-C) in order to facilitate a deterministic reproduction (a replay execution) of the crashed execution. As an example of an analysis problem, a long-running execution might result in the truncation of the recording, and a new suitable starting point for the replay execution has to be determined [11].…”

Section: A Execution Replaymentioning

confidence: 99%

Pinpointing Interrupts in Embedded Real-Time Systems Using Hashed Execution Contexts

Sundmark

Ermedahl

Starner

2009

IEEE Trans. Ind. Inf.

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Cyclic debugging is the process of iteratively re-executing a failed execution in order to determine the cause of the failure, i.e., the bug. In this process, being able to correctly reproduce the faulty execution is an absolute necessity. In sequential, deterministic, non-real-time software, this reproducibility is inherent. However, when the execution is preempted by interrupts, this has severe effects on program reproducibility, since, during the reproduction, it is required for interrupts to occur at the exact same instructions. Previously, this problem has been solved using instruction counters, that induce large execution-time perturbations, or by special hardware solutions which impose a risk of inexact results. In this paper, we propose an alternative method for pinpointing interrupts using hashed values of selected parts of the program execution context. Although our method in some cases can be ambiguous, we show that it serves as a pragmatic method for pinpointing and reproducing interrupts in embedded real-time systems. Moreover, our method does not rely on special hardware or compilers, is simple to implement and use, and requires little execution-time and memory.Index Terms-Debugging aids, real-time systems and embedded systems.

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Starting conditions for post-mortem debugging using deterministic replay of real-time systems

Cited by 2 publications

References 16 publications

A Comprehensive Solution for Deterministic Replay Debugging of SoftPLC Applications

A Comprehensive Solution for Deterministic Replay Debugging of SoftPLC Applications

Pinpointing Interrupts in Embedded Real-Time Systems Using Hashed Execution Contexts

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