1,971 papers · page 55 of 99
In writing parallel programs, programmers expose parallelism and optimize it to meet a particular performance goal on a single platform under an assumed set of workload characteristics. In the field, changing workload characteristics, new parallel platforms, and deployments with …
Energy is increasingly a first-order concern in computer systems. Exploiting energy-accuracy trade-offs is an attractive choice in applications that can tolerate inaccuracies. Recent work has explored exposing this trade-off in programming models. A key challenge, though, is how …
Exploiting today's multiprocessors requires high-performance and correct concurrent systems code (optimising compilers, language runtimes, OS kernels, etc.), which in turn requires a good understanding of the observable processor behaviour that can be relied on. Unfortunately thi…
Existing work that deals with parallelization of complicated reductions and scans focuses only on formalism and hardly dealt with implementation. To bridge the gap between formalism and implementation, we have integrated parallelization via matrix multiplication into compiler con…
Current proposals for concurrent shared-memory languages, including C++ and C, provide sequential consistency only for programs without data races (the DRF guarantee). While the implications of such a contract for hardware optimisations are relatively well-understood, the correct…
Even experienced developers struggle to implement security policies correctly. For example, despite 15 years of development, standard Java libraries still suffer from missing and incorrectly applied permission checks, which enable untrusted applications to execute native calls or…
Wildcards have become an important part of Java's type system since their introduction 7 years ago. Yet there are still many open problems with Java's wildcards. For example, there are no known sound and complete algorithms for subtyping (and consequently type checking) Java wild…
Programming language design benefits from constructs for extending the syntax and semantics of a host language. While C's string-based macros empower programmers to introduce notational shorthands, the parser-level macros of Lisp encourage experimentation with domain-specific lan…
Translation validators are static analyzers that attempt to verify that program transformations preserve semantics. Normalizing translation validators do so by trying to match the value-graphs of an original function and its transformed counterpart. In this paper, we present the …
For decades, compilers have relied on dependence analysis to determine the legality of their transformations. While this conservative approach has enabled many robust optimizations, when it comes to parallelization there are many opportunities that can only be exploited by changi…
In large programs written in managed languages such as Java and C#, holding unnecessary references often results in memory leaks and bloat, degrading significantly their run-time performance and scalability. Despite the existence of many leak detectors for such languages, these d…
Compilers should be correct. To improve the quality of C compilers, we created Csmith, a randomized test-case generation tool, and spent three years using it to find compiler bugs. During this period we reported more than 325 previously unknown bugs to compiler developers. Every …
To derive maximum optimization benefits from partial redundancy elimination (PRE),it is necessary to go beyond its safety constraint. Algorithms for optimal speculative code motion have been developed based on the application of minimum cut to flow networks formed out of the cont…
Although asynchronous communication is an important feature of many concurrent systems, building composable abstractions that leverage asynchrony is challenging. This is because an asynchronous operation necessarily involves two distinct threads of control -- the thread that init…
Self-adjusting computation provides an evaluation model where computations can respond automatically to modifications to their data by using a mechanism for propagating modifications through the computation. Current approaches to self-adjusting computation guarantee correctness b…
Energy-efficient computing is important in several systems ranging from embedded devices to large scale data centers. Several application domains offer the opportunity to tradeoff quality of service/solution (QoS) for improvements in performance and reduction in energy consumptio…
Calling context--the set of active methods on the stack--is critical for understanding the dynamic behavior of large programs. Dynamic program analysis tools, however, are almost exclusively context insensitive because of the prohibitive cost of representing calling contexts at r…
Data races indicate serious concurrency bugs such as order, atomicity, and sequential consistency violations. Races are difficult to find and fix, often manifesting only after deployment. The frequency and unpredictability of these bugs will only increase as software adds paralle…