Showing papers on "Rollback published in 2023"

Effective Access to the Committed Global State in Speculative Parallel Discrete Event Simulation on Multi-core Machines

Abstract: Output production and predicate detection are critical in speculative parallel discrete event simulation, since they need to take place accessing past state values—which have become committed—rather than the current state of the simulation objects, which is possibly affected by causality errors related to speculative event processing. In this article, we present an architecture that enables an effective management of the access to the committed state of any simulation object while still guaranteeing: (i) minimal impact on the forward execution of the simulation in terms of synchronization (and rollback generation) and (ii) highly balanced distribution of the tasks among all the threads running the simulation application. Our architecture is devised for speculative simulation engines running on top of shared-memory parallel machines, where worker threads full share the simulation workload. We exploit kernel-level facilities—targeting the Linux operating system—and user level ones, which work together for enabling a suited wall-clock-time collocation of the threads’ activities for the access to the committed global state of the simulation. We integrated our proposal within the USE (Ultimate Share-Everything) open-source simulation platform, and provide an experimental assessment of it.

Differences in Database Containers

Abstract: I’m old enough to remember the days when Oracle database administrators managed rollback segments by hand. When Oracle introduced automatic undo retention, people (myself included) balked at the idea, confident that it couldn’t manage rollback appropriately. Years later, I can’t imagine a world without that feature!

A Novel Fast Recovery Method for HT Tamper in Embedded Processor

Abstract: Nowadays, embedded processors face various hardware security issues such as hardware trojans (HT) and code tamper attacks. In this paper, a novel cycle-level recovery method for HT tamper in embedded processor is proposed, which consists two units, a General-Purpose Register (GPRs) backup unit and a PC rollback unit. The former one is designed to replace original register files with backup function extra. And the latter one is composed for rollback operations based on the exact PC address corresponding to the wrong instruction. If a HT tamper is detected, the backup unit works in conjunction with PC rollback unit allowing the processor to resume the instruction execution. The proposed method has been implanted into a RISC-V core of PULpino, and the experimental results show that the processor can restore from fault state caused by inserted HT in real time with the latency of 7 clock cycles, including 2 clock cycles for detection.

Cross‐Orogen Granite Migration as an Indicator of Slab Rollback Along Eastern Gondwana

Abstract: Slab rollback during subduction plays a key role in controlling continental growth at convergent plate boundaries. The dynamics of currently subducting slabs can be precisely constrained using geophysical techniques. In contrast, ancient episodes of slab rollback can be difficult to constrain, yet are critical to unlocking the tectonic evolution of long-lived orogens such as the Phanerozoic Australian Tasmanides of eastern Gondwana. Recognition of ancient slab rollback relies on the identification of the progressive migration of magmatic arcs. Here, we investigate the timing and isotopic variation of ∼90 km of the trans-orogen migration of the Carboniferous Bathurst Batholith as a potential indicator of slab rollback. U–Pb–Hf isotopes, combined with a regional zircon Hf isotope data set, suggest that the eastward migration of the batholith over ∼18 Myr, from 340.1 to 322.4 Ma, records a maximum slab steepening rate of ∼0.6–1.2° Myr−1 in a relatively stable trench setting. These results provide a magmatic record of Carboniferous slab rollback and establish a missing link between the long-lived Lachlan and New England orogens of the eastern Gondwanan Tasmanides.

Between Containment and Rollback: The United States and the Cold War in Germany By Christian F. Ostermann. Stanford: Stanford University Press, 2021. Pp. xix + 392. Cloth $45. ISBN: 978-1503606784.

Abstract: Between Containment and Rollback: The United States and the Cold War in Germany By Christian F. Ostermann. Stanford: Stanford University Press, 2021. Pp. xix + 392. Cloth $45. ISBN: 978-1503606784. - Volume 56 Issue 1

Christian F. Ostermann. Between Containment and Rollback: The United States and the Cold War in Germany.

Abstract: Journal Article Christian F. Ostermann. Between Containment and Rollback: The United States and the Cold War in Germany. Get access Christian F. Ostermann. Between Containment and Rollback: The United States and the Cold War in Germany. Stanford, CA: Stanford University Press, 2021. Pp. xix, 392. Cloth $45.00. Hermann Wentker Hermann Wentker Institut für Zeitgeschichte München – Berlin, Germany Email: wentker@ifz-muenchen.de Search for other works by this author on: Oxford Academic Google Scholar The American Historical Review, Volume 128, Issue 2, June 2023, Pages 1032–1034, https://doi.org/10.1093/ahr/rhad200 Published: 22 June 2023

The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling

Abstract: The origin and tectonic evolution of the Gibraltar Arc system is the result of a complex geodynamic evolution involving the convergence of the Eurasian and African plates and the dynamic impact of the Gibraltar slab. Although geologic and geophysical data collected in the last few years have increased our knowledge of the Gibraltar Arc region, it is still unclear which are the mechanical links between the Gibraltar slab and the past deformation of the overriding Alboran lithosphere, as well as to which degree this subduction system is presently active. In this study, we use 2D numerical modelling to investigate the impact of the Gibraltar slab dynamics on the deformation of the overriding Alboran lithosphere. Our model simulates a WE generic vertical section at an approximate latitude of 36°N and considers an initial setup at about Burdigalian times (∼20 Ma), when the subduction front position is relatively well constrained by recent tectonic reconstructions. Our modelling shows a switch in the overriding plate (OP) stress state from extensional stresses during the slab rollback to compressional stresses near the trench when the rollback velocity decreases, caused by the change in slab-induced mantle flow. We also find that much of the crustal and lithospheric deformation occur during fast slab rollback and OP extension in the first 10 Myr of evolution, while after that only moderate deformation associated with subduction is predicted. Finally, we find that despite the subduction rollback ceases, the ongoing motion of the deeper portion of the slab induces a mantle flow that causes some amount of west-directed basal drag of the Alboran lithosphere. This basal drag generates interplate compresional stresses compatible with the distribution of intermediate-depth earthquakes in western Alboran.

Shirakami: A Hybrid Concurrency Control Protocol for Tsurugi Relational Database System

Abstract: Modern real-world transactional workloads such as bills of materials or telecommunication billing need to process both short transactions and long transactions. Recent concurrency control protocols do not cope with such workloads since they assume only classical workloads (i.e., YCSB and TPC-C) that have relatively short transactions. To this end, we proposed a new concurrency control protocol Shirakami. Shirakami has two sub-protocols. Shirakami-LTX protocol is for long transactions based on multiversion concurrency control and Shirakami-OCC protocol is for short transactions based on Silo. Shirakami naturally integrates them with write preservation method and epoch-based synchronization. Shirakami is a module in Tsurugi system, which is a production-purpose relational database system.

SvTPM: SGX-based Virtual Trusted Platform Modules for Cloud Computing

Abstract: Virtual Trusted Platform Modules (vTPMs) are widely used in commercial cloud platforms (e.g., VMware Cloud, Google Cloud, and Microsoft Azure) to provide virtual root-of-trust and security services for virtual machines. Unfortunately, current state-of-the-art vTPM implementations for cloud computing cannot provide strong protection for vTPMs at run-time and suffer from poor performance under binding vTPMs to a physical TPM. In this paper, we propose SvTPM, an SGX-based virtual trusted platform module, which provides complete life cycle protection of vTPMs in the cloud and does not rely on the physical TPM. SvTPM provides strong isolation protection so malicious cloud tenants or even cloud administrators cannot access vTPM's private keys or any other sensitive data. In this paper, we implement a prototype of SvTPM, which identifies and solves a couple of critical security challenges for vTPM protection with SGX, such as NVRAM rollback attacks, NVRAM binding attacks, and vTPM rollback attacks. SvTPM also shows how to establish trust between vTPM and SGX Platform. Our performance evaluation shows that the NVRAM launch time of SvTPM is $1700\times$ faster than vTPM built upon hardware TPM. In TPM standard command evaluation, we find that SvTPM incurs negligible performance overhead while providing strong isolation and protection. To our knowledge, SvTPM is the first practical work to solve the critical security challenges of securing vTPM using SGX.

On the Measurement of Performance Metrics for Virtualization-Enhanced Architectures

Abstract: Cloud computing facilitates resource sharing among multiple users. Although sharing leads to the effective utilization of resources, it raises many security concerns. Hence, virtualization-enabled processors, which are used in cloud computing, are enhanced to provide security. This has put a pressing demand for the measurement of performance metrics for virtualization-enhanced architectures. However, this is a challenging task. Most of the existing simulators do not simulate security-related enhancements in virtualzation-enhanced architectures. Also, software-based simulators are slow. This paper proposes an approach for hardware-based simulation of security-related enhancements in virtualization-enhanced architectures. This is illustrated through the simulation of rollback-sensitive memory architecture like Extended-HyperWall. The results demonstrate that Extended-HyperWall introduces only one extra memory access per memory read/write by the hypervisor or direct memory access controller. Also, it incurs only three additional memory accesses per page during checkpointing and rollback. The paper concludes that virtualization-enabled processors can be efficiently simulated in hardware.

Supplemental Material: Petrology and geochronology of Cretaceous–Eocene plutonic rocks in northeastern Washington, USA: Crustal thickening, slab rollback, and origin of the Challis episode

Abstract: <p>Supplemental File S1: Sample locations and elemental and isotopic data. Supplemental File S2: U-Pb ranked age plots and concordia diagrams. Supplemental File S3: U-Pb method details and all individual point analyses. </p>

Supplemental Material: Petrology and geochronology of Cretaceous–Eocene plutonic rocks in northeastern Washington, USA: Crustal thickening, slab rollback, and origin of the Challis episode

Abstract: <p>Supplemental File S1: Sample locations and elemental and isotopic data. Supplemental File S2: U-Pb ranked age plots and concordia diagrams. Supplemental File S3: U-Pb method details and all individual point analyses. </p>

Rollback Recovery in Session-Based Programming

Abstract: To react to unforeseen circumstances or amend abnormal situations in communication-centric systems, programmers are in charge of “undoing” the interactions which led to an undesired state. To assist this task, session-based languages can be endowed with reversibility mechanisms. In this paper we propose a language enriched with programming facilities to commit session interactions, to roll back the computation to a previous commit point, and to abort the session. Rollbacks in our language always bring the system to previous visited states and a rollback cannot bring the system back to a point prior to the last commit. Programmers are relieved from the burden of ensuring that a rollback never restores a checkpoint imposed by a session participant different from the rollback requester. Such undesired situations are prevented at design-time (statically) by relying on a decidable compliance check at the type level, implemented in MAUDE. We show that the language satisfies error-freedom and progress of a session.

Quantum architecture search via truly proximal policy optimization

Abstract: Quantum Architecture Search (QAS) is a process of voluntarily designing quantum circuit architectures using intelligent algorithms. Recently, Kuo et al. (Quantum architecture search via deep reinforcement learning. arXiv preprint arXiv:2104.07715, 2021) proposed a deep reinforcement learning-based QAS (QAS-PPO) method, which used the Proximal Policy Optimization (PPO) algorithm to automatically generate the quantum circuit without any expert knowledge in physics. However, QAS-PPO can neither strictly limit the probability ratio between old and new policies nor enforce well-defined trust domain constraints, resulting in poor performance. In this paper, we present a new deep reinforcement learning-based QAS method, called Trust Region-based PPO with Rollback for QAS (QAS-TR-PPO-RB), to automatically build the quantum gates sequence from the density matrix only. Specifically, inspired by the research work of Wang, we employ an improved clipping function to implement the rollback behavior to limit the probability ratio between the new strategy and the old strategy. In addition, we use the triggering condition of the clipping based on the trust domain to optimize the policy by restricting the policy within the trust domain, which leads to guaranteed monotone improvement. Experiments on several multi-qubit circuits demonstrate that our presented method achieves better policy performance and lower algorithm running time than the original deep reinforcement learning-based QAS method.

Automatic Rollback Suggestions for Incremental Datalog Evaluation

Abstract: Advances in incremental Datalog evaluation strategies have made Datalog popular among use cases with constantly evolving inputs such as static analysis in continuous integration and deployment pipelines. As a result, new logic programming debugging techniques are needed to support these emerging use cases. This paper introduces an incremental debugging technique for Datalog, which determines the failing changes for a rollback in an incremental setup. Our debugging technique leverages a novel incremental provenance method. We have implemented our technique using an incremental version of the Soufflé Datalog engine and evaluated its effectiveness on the DaCapo Java program benchmarks analyzed by the Doop static analysis library. Compared to state-of-the-art techniques, we can localize faults and suggest rollbacks with an overall speedup of over 26.9 $$\times $$ while providing higher quality results.