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The rate of network packets encapsulating requests from clients can significantly affect the utilization, and thus performance and sleep states of processors in servers deploying a power management policy. To improve energy efficiency, servers may adopt an aggressive power management policy that frequently transitions a processor to a low-performance or sleep state at a low utilization. However, such...
Processor hardware performance counters have recently improved in quality and features, while performance monitoring support in Linux has been significantly revamped with the development of the perf_events subsystem, which contributed in making performance analysis an increasingly common practice among developers. However, no performance analysis is possible without an efficient monitoring interface...
Single-ISA heterogeneous multicore processors have gained increasing popularity with the introduction of recent technologies such as ARM big.LITTLE. These processors offer increased energy efficiency through combining low power in-order cores with high performance out-of-order cores. Efficiently exploiting this attractive feature requires careful management so as to meet the demands of targeted applications...
Virtualization has become a key technology used in modern data centers. What began as a tool for server consolidation and energy efficiency has grown into an enabler for cloud computing. Cloud computing has become an accepted best practice for data centers. Virtualization is also becoming a key component of embedded and real-time systems in automotive systems, game consoles, and industrial settings...
The memory subsystem of modern multi-core architectures is becoming more and more complex with the increasing number of cores integrated in a single computer system. This complexity leads to profiling needs to let software developers understand how programs use the memory subsystem. Modern processors come with hardware profiling features to help building tools for these profiling needs. Regarding...
Process schedulers are part of the core functionality of an operating system (OS), and have been enhanced over the years to account for multiple cores in the processors and to support multi-threaded applications. In this study, we investigate the impact of the Linux scheduler's load-balancing algorithm on the performance of multi-threaded OpenSIPS (an open source SIP proxy server, SPS) running on...
The scheduling a set of periodic/sporadic real-time tasks on multiprocessor computing platform to achieve full system utilization with reduced overhead has been identified as a difficult problem and was well studied in the past. Proportional Fair (PFair) and Boundary Fair (BFair) are two optimal scheduling algorithms for discrete time multiprocessor systems. Here, PFair and its variants can handle...
To reduce the manpower and response time for surveillance systems at low cost, in this paper, an ARM-based embedded system dedicated for unattended realtime moving target detection is constructed. The comprehensive procedures in building up an embedded system such as setup environment for cross-compilation, migration of Bootloader, migration of Linux-2.6 kernel, fabrication and migration of root document...
Turning towards exascale systems and beyond, it has been widely argued that the currently available systems software is not going to be feasible due to various requirements such as the ability to deal with heterogeneous architectures, the need for systems level optimization targeting specific applications, elimination of OS noise, and at the same time, compatibility with legacy applications. To cope...
A number of simple performance measurements on disk speed, CPU, memory and network throughput were done on a dual ARM Cortex-A7 machine running Linux inside a Xen virtual machine that communicate with the outside through fronted-driver and backend-driver. The average performance overhead of Xen virtual machine is between 3 and 7 percent when the host is lightly loaded (running only the system software...
Almost all DNS queries that traverse Internet are transported via UDP in self-contained small packages. Therefore, with no restriction of packet ordering, the intuition would say that adding thread-based parallelism to the servers will increase their performance, but it does not. This paper studies the problem of serialized access to UDP sockets, and states the problem in the way the packets are enqueued...
System Management Mode (SMM) in x86 has enabled a new class of malware with incredible power to control physical hardware that is virtually impossible to detect by the host operating system. Previous SMM root kits have only scratched the surface by modifying kernel data structures and trapping on I/O registers to implement PS/2 key loggers. In this paper, we present new SMM-based malware that hijacks...
LIKWID is a set of performance-related command line tools targeting X86 processors. Besides affinity-related tools it also includes likwid-perfctr, which allows to count hardware performance events. LIKWID builds upon the Linux msr kernel module, which allows to access model-specific registers (MSRs) via a device file interface. In addition to a set of convenient functional features such as a logical...
Signal handling has been an integral part of UNIX systems since the earliest implementation in the 1970s. Nowadays, we find signals in all common flavors of UNIX systems, including BSD, Linux, Solaris, Android, and Mac OS. While each flavor handles signals in slightly different ways, the implementations are very similar. In this paper, we show that signal handling can be used as an attack method in...
Valgrind is a Dynamic Binary Analysis tool used for debugging and profiling purposes. It's mostly used to analyze the memory usage of software applications. Currently it supports the ×86, AMD, ARM, PPC and S390X architectures. Recently it has been ported to MIPS/Linux. This paper describes VG-MIPS a port of Valgrind to Cavium Networks®'s Octeon Processor for intelligent networking which hosts a MIPS64...
Loongson is a family of general purpose processors based on MIPS architecture designed and manufactured in Mainland China. With the maturity of Loongson CPUs, applications are widely available with the increasing development of software tools and hardware platforms by research teams in academia and industry. In recent years, products based on Loongson have been mainly used in education, personal computers...
We present ODLV: an on-demand lightweight virtualization mechanism to solve the "lying endpoint problem" in TCG-TNC. ODLV utilizes dynamic root of trust and virtualization technologies of new commodity processors from Intel and AMD to dynamically establish a chain of trust and to insert a Lightweight Virtual Machine Manager (LVMM) under commodity Operating System (OS). The LVMM protects...
Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation and applying hierarchical scheduling techniques. Over the years, the study of virtual cluster scheduling has been limited to theoretical analysis. In this paper, we present our...
Nowadays, embedded systems treats larger data than ever before. It can be expected that the size of data treated by embedded systems will be increased. In ordinary case, these complicated requirements are achieved with adopting OS(operating system) kernel to systems. To improve the performance of OS kernel's data processing is meaningful for many embedded solutions. To achieve this improvement, we...
I/O devices are evolving rapidly, while OS optimization is always slower because of its dependence on physical devices. This inevitably prevents latest devices from working with their rating performance, which remains a big problem for performance-critical applications. Though I/O device simulators can help carry out performance evaluation before physical devices are ready, the existing simulator...
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