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Maintenance of virtualized datacenters is often needed for the purposes of introducing new features, fixing bugs or mitigating security problems. However, current maintenance methods are either highly disruptive to the operation of VMs, utilize ...

• Two-pronged solution combines in-place transplant and live migration to simplify the securing and updating of hypervisors.
• Multiple transplantation directions supported, between same or different hypervisors.
• In-place transplant ...

Coccinelle is a program matching and transformation engine for C code. This paper introduces the use of Coccinelle through a collection of examples targeting evolutions and bug fixes in the Linux kernel.

The Android operating system is frequently updated, with each version bringing a new set of APIs. New versions may involve API deprecation; Android apps using deprecated APIs need to be updated to ensure the apps’ compatibility with old and new ...

To best support highly parallel applications, Linux's CFS scheduler tends to spread tasks across the machine on task creation and wakeup. It has been observed, however, that in a server environment, such a strategy leads to tasks being unnecessarily ...

Nowadays, there is a shift in the deployment model of Cloud and Edge applications. Applications are now deployed as a set of several small units communicating with each other - the microservice model. Moreover, each unit - a microservice, may be ...

The Android operating system (OS) is often updated, where each new version may involve API deprecation. Usages of deprecated APIs in Android apps need to be updated to ensure the apps' compatibility with the old and new versions of the Android OS. In ...

The vulnerability window of a hypervisor regarding a given security flaw is the time between the identification of the flaw and the integration of a correction/patch in the running hypervisor. Most vulnerability windows, regardless of severity, are long ...

Nested/Extended Page Table (EPT) is the current hardware solution for virtualizing memory in virtualized systems. It induces a significant performance overhead due to the 2D page walk it requires, thus 24 memory accesses on a TLB miss (instead of 4 ...

In modern server CPUs, individual cores can run at different frequencies, which allows for fine-grained control of the performance/ energy tradeoff. Adjusting the frequency, however, incurs a high latency. We find that this can lead to a problem of ...

In a large software system such as the Linux kernel, there is a continual need for large-scale changes across many source files, triggered by new needs or refined design decisions. In this paper, we propose to ease such changes by suggesting ...

Due to the deprecation of APIs in the Android operating system, developers have to update usages of the APIs to ensure that their applications work for both the past and current versions of Android. Such updates may be widespread, non-trivial, and time-...

Recent research and bug reports have shown that work conservation, the property that a core is idle only if no other core is overloaded, is not guaranteed by Linux's CFS or FreeBSD's ULE multicore schedulers. Indeed, multicore schedulers are challenging ...

The complexity of computer architectures has risen since the early years of the Linux kernel: Simultaneous Multi-Threading (SMT), multicore processing, and frequency scaling with complex algorithms such as Intel® Turbo Boost have all become omnipresent. ...

A challenge in designing cooperative distributed systems is to develop feasible and cost-effective mechanisms to foster cooperation among selfish nodes, i.e., nodes that strategically deviate from the intended specification to increase their individual ...

This paper addresses the problem of efficiently virtualizing NUMA architectures. The major challenge comes from the fact that the hypervisor regularly reconfigures the placement of a virtual machine (VM) over the NUMA topology. However, neither guest ...

The Coccinelle C-program matching and transformation tool was first released in 2008 to facilitate specification and automation in the evolution of Linux kernel code. The novel contribution of Coccinelle was that it allows software developers to write ...

This paper analyzes the impact on application performance of the design and implementation choices made in two widely used open-source schedulers: ULE, the default FreeBSD scheduler, and CFS, the default Linux scheduler. We compare ULE and CFS in ...

Bitslicing is a programming technique commonly used in cryptography that consists in implementing a combinational circuit in software. It results in a massively parallel program immune to cache-timing attacks by design.

However, writing a program in ...

Porting Linux device drivers to target more recent and older Linux kernel versions to compensate for the everchanging kernel interface is a continual problem for Linux device driver developers. Acquiring information about interface changes is a ...

Operating systems have been shown to waste machine resources by leaving cores idle while work is ready to be scheduled. This results in suboptimal performance for user applications, and wasted power.

Recent progress in formal verification methods have ...