Latency (engineering)

About: Latency (engineering) is a research topic. Over the lifetime, 7278 publications have been published within this topic receiving 115409 citations. The topic is also known as: lag.

Analysis and design of the google congestion control for web real-time communication (WebRTC)

Abstract: Video conferencing applications require low latency and high bandwidth. Standard TCP is not suitable for video conferencing since its reliability and in order delivery mechanisms induce large latency. Recently the idea of using the delay gradient to infer congestion is appearing again and is gaining momentum. In this paper we present an algorithm that is based on estimating through a Kalman filter the end-to-end one way delay variation which is experienced by packets traveling from a sender to a destination. This estimate is compared to an adaptive threshold to dynamically throttle the sending rate. The control algorithm has been implemented over the RTP/RTCP protocol and is currently used in Google Hangouts and in the Chrome WebRTC stack. Experiments have been carried out to evaluate the algorithm performance in the case of variable link capacity, presence of heterogeneous or homogeneous concurrent traffic, and backward path traffic.

Using destination-set prediction to improve the latency/bandwidth tradeoff in shared-memory multiprocessors

Abstract: Destination-set prediction can improve the latency/bandwidth tradeoff in shared-memory multiprocessors The destination set is the collection of processors that receive a particular coherence request Snooping protocols send requests to the maximal destination set (ie, all processors), reducing latency for cache-to-cache misses at the expense of increased traffic Directory protocols send requests to the minimal destination set, reducing bandwidth at the expense of an indirection through the directory for cache-to-cache misses Recently proposed hybrid protocols trade-off latency and bandwidth by directly sending requests to a predicted destination setThis paper explores the destination-set predictor design space, focusing on a collection of important commercial workloads First, we analyze the sharing behavior of these workloads Second, we propose predictors that exploit the observed sharing behavior to target different points in the latency/bandwidth tradeoff Third, we illustrate the effectiveness of destination-set predictors in the context of a multicast snooping protocol For example, one of our predictors obtains almost 90% of the performance of snooping while using only 15% more bandwidth than a directory protocol (and less than half the bandwidth of snooping)

Cytomegalovirus latency and reactivation: recent insights into an age old problem.

Abstract: Human cytomegalovirus (HCMV) infection remains a major cause of morbidity in patient populations. In certain clinical settings, it is the reactivation of the pre-existing latent infection in the host that poses the health risk. The prevailing view of HCMV latency was that the virus was essentially quiescent in myeloid progenitor cells and that terminal differentiation resulted in the initiation of the lytic lifecycle and reactivation of infectious virus. However, our understanding of HCMV latency and reactivation at the molecular level has been greatly enhanced through recent advancements in systems biology approaches to perform global analyses of both experimental and natural latency. These approaches, in concert with more classical reductionist experimentation, are furnishing researchers with new concepts in cytomegalovirus latency and suggest that latent infection is far more active than first thought. In this review, we will focus on new studies that suggest that distinct sites of cellular latency could exist in the human host, which, when coupled with recent observations that report different transcriptional programmes within cells of the myeloid lineage, argues for multiple latent phenotypes that could impact differently on the biology of this virus in vivo. Finally, we will also consider how the biology of the host cell where the latent infection persists further contributes to the concept of a spectrum of latent phenotypes in multiple cell types that can be exploited by the virus.

Method and apparatus for reducing latency in waking up a group of dormant communication devices

Abstract: A method and apparatus for reducing dormand-wakeup latency in a group communication network (100) provides for a significant reduction in the actual total dormant-wakeup time and the PTT{XE'PTT'} latency perceived by the talker through caching the network-initiated wakeup tiggers destined for target listeners, and delivering a wakeup trigger to a target mobile station (104, 1o6, 108) as soon as the target mobile station has re-established its traffic channel.