Optimal Reissue Policies for Reducing Tail Latency

Interactive services send redundant requests to multiple different replicas to meet stringent tail latency requirements. These addi- tional (reissue) requests mitigate the impact of non-deterministic delays within the system and thus increase the probability of re- ceiving an on-time response. There are two existing approaches of using reissue requests to reduce tail latency. (1) Reissue requests immediately to one or more replicas, which multiplies the load and runs the risk of overloading the system. (2) Reissue requests if not completed after a fixed delay. The delay helps to bound the number of extra reissue requests, but it also reduces the chance for those requests to respond before a tail latency target. We introduce a new family of reissue policies, Single-Time / Random ( SingleR ), that reissue requests after a delay d with probability q . SingleR employs randomness to bound the reissue rate, while allowing requests to be reissued early enough so they have sufficient time to respond, exploiting the benefits of both immediate and delayed reissue of prior work. We formally prove, within a simplified analytical model, that SingleR is optimal even when compared to more complex policies that reissue multiple times. To use SingleR for interactive services, we provide efficient algorithms for calculating optimal reissue delay and probability from response time logs through data-driven approach. We apply itera- tive adaptation for systems with load-dependent queuing delays. The key advantage of this data-driven approach is its wide applica- bility and effectiveness to systems with various design choices and workload properties. We evaluated SingleR policies thoroughly. We use simulation to illustrate its internals and demonstrate its robustness to a wide range of workloads. We conduct system experiments on the Re- dis key-value store and Lucene search server. The results show that for utilizations ranging from 40 - 60% , SingleR reduces the 99 th-percentile latency of Redis by 30 - 70% by reissuing only 2% of requests, and the 99 th-percentile latency of Lucene by 15 - 25% by reissuing 1% only

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About the current lexical productivity of the word-forming element “cyber”

Cyber is a neologism based on cybernetics, a term popularized by the American mathematician Norbert Wiener in the 1940s. Wiener derived it from the Greek word kubernētēs, which refers to a pilot or steersman. From that, a slew of words came into existence to describe everything from people’s names to types of crime. This article describes the productivity that cyber has recently achieved in the French language. The corpus that is examined is formed from French dictionaries, lists of neologisms from the French review La Banque des mots, and from the Néoveille Platform. The search results for compounds starting with cyber are obtained by means of automatic detection, manual validation, and linguistic description. The study is also based on the comparable web corpus Aranea. In this paper the notion of a fracto-lexeme is used for the word-forming element cyber. Two of the earliest compound words starting with cyber that came into common usage are cyberspace and cyberpunk, but many other words became particularly popular in the 1990s. The majority of the words that appear after cyber are people’s names; 432 of them were found in the corpus. The study showed that cyber is part of a few thousand compound words, and can be attached to almost anything to make it sound futuristic or technical. This fracto-lexeme is, therefore, firmly rooted in the French language, but some prefer the short “e-” or “online”.Cyber est un néologisme basé sur la cybernétique, terme popularisé par le mathématicien américain Norbert Wiener dans les années 1940. Wiener l’a dérivé du grec kubernētēs qui fait référence à un pilote de navire. Et depuis lors, beaucoup de mots sont créés pour décrire entre autres tout ce qui a trait à des appellations de personnes. Cet article décrit la productivité actuelle de cyber en français. Le corpus examiné est constitué de fracto-composés retenus dans des dictionnaires français et dans les listes de néologismes répertoriés par la revue La Banque des mots et par la plate-forme Néoveille. Les résultats des créations avec cyber sont obtenus à partir de la détection automatique, de la validation manuelle et de la description linguistique. L’étude est également basée sur la recherche dans le corpus Aranea. Dans cet article, on utilise pour désigner l’élément cyber la notion de fracto-lexème. Cyberespace et cyberpunk sont les deux premiers mots composés avec cyber qui sont devenus d’usage courant, mais de nombreux autres mots se sont popularisés dans les années 1990. La majorité des mots qui apparaissent après cyber sont des appellations de personnes, il y en a 432 dans le corpus recueilli. L’étude montre que cyber fait partie de quelques centaines de mots composés. Il peut être rattaché à presque tout mot pour former un mot composé ayant une signification technique. Ce fracto-lexème est donc fermement ancré en français, mais certains locuteurs privilégient « e- » ou « en ligne » à la place de cyber

Ways of Knowing When Research Subjects Care

This paper investigates a hidden dimension of research with real world stakes: research subjects who care -- sometimes deeply -- about the topic of the research in which they participate. They manifest this care, we show, by managing how they are represented in the research process, by exercising politics in shaping knowledge production, and sometimes in experiencing trauma in the process. We draw first-hand reflections on participation in diversity research on Wikipedia, transforming participants from objects of study to active negotiators of research process. We depict how care, vulnerability, harm, and emotions shape ethnographic and qualitative data. We argue that, especially in reflexive cultures, research subjects are active agents with agendas, accountabilities, and political projects of their own. We propose ethics of care and collaboration to open up new possibilities for knowledge production and socio-technical intervention in HCI