14795008
The design methodology of Phoenix cluster system software stack
Though many research groups have explored the design methodology of cluster system software stack, few works discuss what constitutes a good one. In this paper, we choose four criteria throughout the lifecycle of cluster system software stack to evaluate its design methodology, including code reusability, evolveability, adaptability and manageability. According to the four criteria, we have proposed a management service-based layered design methodology and built a complete cluster system software stack for both scientific and business computing. Our practices and evaluations show our design methodology has advantages over others in terms of the proposed criteria.
752937
In cloud, do MTC or HTC service providers benefit from the economies of scale?
Cloud computing, which is advocated as an economic platform for daily computing, has become a hot topic for both industrial and academic communities in the last couple of years. The basic idea behind cloud computing is that resource providers, which own the cloud platform, offer elastic resources to end users. In this paper, we intend to answer one key question to the success of cloud computing: in cloud, do many task computing (MTC) or high throughput computing (HTC) service providers, which offer the corresponding computing service to end users, benefit from the economies of scale? To the best of our knowledge, no previous work designs and implements the enabling system to consolidate MTC and HTC workloads on the cloud platform and no one answers the above question. Our research contributions are threefold: first, we propose an innovative usage model, called dynamic service provision (DSP) model, for MTC or HTC service providers. In the DSP model, the resource provider provides the service of creating and managing runtime environments for MTC or HTC service providers, and consolidates heterogeneous MTC or HTC workloads on the cloud platform; second, based on the DSP model, we design and implement Dawningcloud, which provides automatic management for heterogeneous workloads; third, a comprehensive evaluation of Dawningcloud has been performed in an emulatation experiment. We found that for typical workloads, in comparison with the previous two cloud solutions, Dawningcloud saves the resource consumption maximally by 46.4% (HTC) and 74.9% (MTC) for the service providers, and saves the total resource consumption maximally by 29.7% for the resource provider. At the same time, comparing with the traditional solution that provides MTC or HTC services with dedicated systems, Dawningcloud is more cost-effective. To this end, we conclude that for typical MTC and HTC workloads, on the cloud platform, MTC and HTC service providers and the resource service provider can benefit from the economies of scale.
10848491
Detecting and Eliminating Potential Violations of Sequential Consistency for Concurrent C/C++ Programs
When a concurrent shared-memory program written with a sequential consistency (SC) model is run on a machine implemented with a relaxed consistency (RC) model, it could cause SC violations that are very hard to debug. To avoid such violations, programmers need to provide explicit synchronizations or insert fence instructions. In this paper, we propose a scheme to detect and eliminate potential SC violations by combining Shasha/Snir's conflict graph and delay set theory with existing data race detection techniques. For each execution, we generate a race graph, which contains the improperly synchronized conflict accesses, called race accesses, and race cycles formed with those accesses. As a race cycle would probably lead to a non-sequential-consistent execution, we call it a potential violation of sequential consistency (PVSC) bug. We then compute the race delays of race cycles, and suggest programmers to insert fences into source code to eliminate PVSC bugs. We further convert a race graph into a PC race graph, and improves cycle detection and race delay computation to O(n^2), where n is the number of race access instructions. We evaluate our approach with the SPLASH-2 benchmarks, two large real-world applications (MySQL and Apache), and several multi-threaded Cilk programs. The results show that (1) the proposed approach could effec-tively detect PVSC bugs in real-world applications with good scalability; (2) it retains most of the performance of the concurrent program after inserting required fence instructions, with less than 6.3% performance loss; and (3) the additional cost of our approach over traditional race detection techniques is quite low, with 3.3% on average.
12523556
Design Patterns of Scalable Cluster System Software
The design pattern of cluster system software has an important influence on scalability of massive cluster system. The paper presents design patterns of scalable cluster system software, including scalable software topologies and optimized communication modes. These design patterns have been widely applied in Dawning series of supercomputers and some results of performance evaluation show their good scalability
11038275
Exploiting idle register classes for fast spill destination
On today's microprocessors, there often exist several different types of registers, e.g. general purpose registers and floating point registers. A given program may use one type of registers much more frequently than other types. This creates an opportunity to employ the infrequently used registers as spill destinations for the more frequently used register types. In this paper, we present a code optimization method named idle register exploitation (IRE) to exploit such opportunities. We developed a model, called the IRE model, or IREM, to determine the static performance gains of IRE versus spilling to the stack. On a microprocessor with fast data paths between different types of registers, we find that IRE method speeds up the execution of the SPECint benchmark suite from 1.7% to 10%. In contrast, on microprocessors with less efficient data transfer paths, the performance gain is limited. In some cases, performance may even suffer degradation. This result argues strongly for the adoption of fast data paths between different types of registers for the purpose of reducing register spills, which is important in view of the increased significance of memory bottlenecks on future microprocessors.
2643198
Easy and reliable cluster management: the self-management experience of Fire Phoenix
High-Performance clusters are rapidly becoming an important computing platform for both scientific and business applications. To fulfil the new demands and challenges, cluster system software is inevitably complex. Even for experienced administrators, the management of a cluster system is an exhausting job. This paper introduces Fire Phoenix, a scalable and self-managing cluster system software that supports both scientific and commercial applications. With the self-configuring and self-healing features, much of the machine configuration and error recovery can be done automatically. Our design has been proven effective in the operations of the Dawning 4000A supercomputer, which is the biggest cluster system in China
35028524
SmartOSEK: A Real-Time Operating System for Automotive Electronics
This paper puts forward SmartOSEK, a dependable platform for automobile electronics, which consists of an operating system compliant with OSEK/VDX specifications and an integrated development environment (IDE) that consists of many convenient tools, such as visual designer, system generator, time analyst, scheduling analyst, and running tracer. In the operating system, SmartOSEK OS and SmartOSEK COM are presented. In the IDE, we apply the graphic design, automatic code generation and time analysis to help developers devote their mind to the modeling of the applications. A design example of automated transmission system based on SmartOSEK platform is given, and good results are achieved.
17470669
Retrieval with knowledge-driven kernel design: an approach to improving SVM-based CBIR with relevance feedback
The performance of SVM-based image retrieval is often constrained by the scarcity of training samples. The total number of image samples labeled by users in a retrieval session is very limited, and this small number of labeled samples cannot effectively represent the true distributions of positive and negative image classes, especially for the negative image class. This paper proposes a novel approach to deal with this problem. Instead of treating it as a problem, the mere existence of the small number of labeled images and their desired distribution in the kernel space is considered as prior knowledge from image retrieval to aid the design of the kernel used by SVMs. This is achieved by maximizing a criterion, such as one based on scatter matrices, through gradient-based search methods, incurring very little computational overhead to real-time retrieval process. Experimental results on two benchmark image databases demonstrate the improved retrieval performance by the dynamically designed kernel and hence the effectiveness of the proposed approach for SVM based image retrieval
9035268
Optimally Balanced Forward Degree Sequence
Forward degree seqences, arising from orderings of the vertices in a graph, carry a lot of vital information about the graph. In this paper, we focus our work on two special classes of forward degree sequences, which we named balanced and strongly balanced. Our main result is to prove that any chordal graph has a strongly balanced forward degree sequence and any graph with all degrees at most 3 has a balanced forward degree sequence. Moreover, we show that the strongly balanced forward degree sequence can be computed in polynomial time in the above cases.
120181133
Face recognition based on discriminative manifold learning
In this paper, a discriminative manifold learning method for face recognition is proposed which achieved the discriminative embedding the high dimensional face data into a low dimensional hidden manifold. Unlike the recently proposed LLE, Isomap and Eigenmap algorithms, which are based on reconstruction purpose, our method uses the RCA algorithm to achieve nonlinear embedding and data discrimination at the same time. Also, the LLE and Isomap algorithms are crucially depends on the appropriateness of the neighborhood construction rule, in this paper, a CK-nearest neighborhood rule is proposed to achieve better neighborhood construction. Experimental results indicate the promising performance of the proposed method.
2805830
Kapa: A File Sharing System Based on HP2P
In this paper, we present Kapa, a new file sharing system based on HP2P which is a two-layer hybrid P2P network that combines the strongpoint of DHT and flooding methods to improve the performance of whole system. The design of Kapa, including the HP2P and the file sharing modules, is introduced in detail. By the analysis and simulation of Kapa, we conclude that Kapa is good at scalability, efficiency, and stability.