Author
Tai Jin
Bio: Tai Jin is an academic researcher from Hewlett-Packard. The author has contributed to research in topics: Cache & Web server. The author has an hindex of 16, co-authored 19 publications receiving 3739 citations.
Topics: Cache, Web server, Web service, Server, Cache pollution
Papers
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01 Dec 1998
TL;DR: In this article, the authors describe a tool for measuring web server performance called httperf, which provides a flexible facility for generating various HTTP workloads and for measuring server performance.
Abstract: This paper describes httperf, a tool for measuring web server performance. It provides a flexible facility for generating various HTTP workloads and for measuring server performance. The focus of httperf is not on implementing one particular benchmark but on providing a robust, high-performance tool that facilitates the construction of both micro- and macro-level benchmarks. The three distinguishing characteristics of httperf are its robustness, which includes the ability to generate and sustain server overload, support for the HTTP/1.1 protocol, and its extensibility to new workload generators and performance measurements. In addition to reporting on the design and implementation of httperf this paper also discusses some of the experiences and insights gained while realizing this tool.
909 citations
TL;DR: It is found that improvements in the caching architecture of the World Wide Web are changing the workloads of Web servers, but major improvements to that architecture are still necessary.
Abstract: This article presents a detailed workload characterization study of the 1998 World Cup Web site. Measurements from this site were collected over a three-month period. During this time the site received 1.35 billion requests, making this the largest Web workload analyzed to date. By examining this extremely busy site and through comparison with existing characterization studies, we are able to determine how Web server workloads are evolving. We find that improvements in the caching architecture of the World Wide Web are changing the workloads of Web servers, but major improvements to that architecture are still necessary. In particular, we uncover evidence that a better consistency mechanism is required for World Wide Web caches.
743 citations
01 Jan 2000
TL;DR: In this article, a detailed workload characterization study of the 1998 World Cup Web site is presented, showing that improvements in the caching architecture of the World Wide Web are changing the workloads of Web servers, but major improvements to that architecture are still necessary.
Abstract: This article presents a detailed workload characterization study of the 1998 World Cup Web site. Measurements from this site were collected over a three-month period. During this time the site received l .35 billion re uests, making this the largest throu h comparison with existing characterization studies, we are able to determinelow W eb server workloads are evolving. We find that improvements in the caching architecture of the World Wide Web are changing the workloads of Web servers, but major im rovements to that architecture are still necessary. In particular, we uncover evilence that a better consistency mechanism is required for World Wide Web caches. Web workload analyzed to date. By examining a t is extremely busy site and
711 citations
01 Mar 2000
TL;DR: A trace of client requests to a busy Web proxy in an ISP environment is utilized to evaluate the performance of several existing replacement policies and of two new, parameterless replacement policies that are introduced in this paper.
Abstract: The continued growth of the World-Wide Web and the emergence of new end-user technologies such as cable modems necessitate the use of proxy caches to reduce latency, network traffic and Web server loads. Current Web proxy caches utilize simple replacement policies to determine which files to retain in the cache. We utilize a trace of client requests to a busy Web proxy in an ISP environment to evaluate the performance of several existing replacement policies and of two new, parameterless replacement policies that we introduce in this paper. Finally, we introduce Virtual Caches, an approach for improving the performance of the cache for multiple metrics simultaneously.
284 citations
Patent•
22 Mar 1999TL;DR: In this article, a cache system is described that includes a storage that is partitioned into a plurality of storage areas, each for storing one kind of objects received from remote sites and to be directed to target devices.
Abstract: A cache system is described that includes a storage that is partitioned into a plurality of storage areas, each for storing one kind of objects received from remote sites and to be directed to target devices. The cache system further includes a cache manager coupled to the storage to cause objects to be stored in the corresponding storage areas of the storage. The cache manager causes cached objects in each of the storage areas to be replaced in accordance with one of a plurality of replacement policies, each being optimized for one kind of objects.
197 citations
Cited by
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TL;DR: This paper defines Cloud computing and provides the architecture for creating Clouds with market-oriented resource allocation by leveraging technologies such as Virtual Machines (VMs), and provides insights on market-based resource management strategies that encompass both customer-driven service management and computational risk management to sustain Service Level Agreement (SLA) oriented resource allocation.
5,850 citations
TL;DR: This paper demonstrates the benefits of cache sharing, measures the overhead of the existing protocols, and proposes a new protocol called "summary cache", which reduces the number of intercache protocol messages, reduces the bandwidth consumption, and eliminates 30% to 95% of the protocol CPU overhead, all while maintaining almost the same cache hit ratios as ICP.
Abstract: The sharing of caches among Web proxies is an important technique to reduce Web traffic and alleviate network bottlenecks. Nevertheless it is not widely deployed due to the overhead of existing protocols. In this paper we demonstrate the benefits of cache sharing, measure the overhead of the existing protocols, and propose a new protocol called "summary cache". In this new protocol, each proxy keeps a summary of the cache directory of each participating proxy, and checks these summaries for potential hits before sending any queries. Two factors contribute to our protocol's low overhead: the summaries are updated only periodically, and the directory representations are very economical, as low as 8 bits per entry. Using trace-driven simulations and a prototype implementation, we show that, compared to existing protocols such as the Internet cache protocol (ICP), summary cache reduces the number of intercache protocol messages by a factor of 25 to 60, reduces the bandwidth consumption by over 50%, eliminates 30% to 95% of the protocol CPU overhead, all while maintaining almost the same cache hit ratios as ICP. Hence summary cache scales to a large number of proxies. (This paper is a revision of Fan et al. 1998; we add more data and analysis in this version.).
2,174 citations
30 Mar 2011
TL;DR: The results show that Mesos can achieve near-optimal data locality when sharing the cluster among diverse frameworks, can scale to 50,000 (emulated) nodes, and is resilient to failures.
Abstract: We present Mesos, a platform for sharing commodity clusters between multiple diverse cluster computing frameworks, such as Hadoop and MPI. Sharing improves cluster utilization and avoids per-framework data replication. Mesos shares resources in a fine-grained manner, allowing frameworks to achieve data locality by taking turns reading data stored on each machine. To support the sophisticated schedulers of today's frameworks, Mesos introduces a distributed two-level scheduling mechanism called resource offers. Mesos decides how many resources to offer each framework, while frameworks decide which resources to accept and which computations to run on them. Our results show that Mesos can achieve near-optimal data locality when sharing the cluster among diverse frameworks, can scale to 50,000 (emulated) nodes, and is resilient to failures.
1,786 citations
21 Oct 2001
TL;DR: Experimental results from a prototype confirm that the system adapts to offered load and resource availability, and can reduce server energy usage by 29% or more for a typical Web workload.
Abstract: Internet hosting centers serve multiple service sites from a common hardware base. This paper presents the design and implementation of an architecture for resource management in a hosting center operating system, with an emphasis on energy as a driving resource management issue for large server clusters. The goals are to provision server resources for co-hosted services in a way that automatically adapts to offered load, improve the energy efficiency of server clusters by dynamically resizing the active server set, and respond to power supply disruptions or thermal events by degrading service in accordance with negotiated Service Level Agreements (SLAs).Our system is based on an economic approach to managing shared server resources, in which services "bid" for resources as a function of delivered performance. The system continuously monitors load and plans resource allotments by estimating the value of their effects on service performance. A greedy resource allocation algorithm adjusts resource prices to balance supply and demand, allocating resources to their most efficient use. A reconfigurable server switching infrastructure directs request traffic to the servers assigned to each service. Experimental results from a prototype confirm that the system adapts to offered load and resource availability, and can reduce server energy usage by 29% or more for a typical Web workload.
1,492 citations
TL;DR: An inventory of the world’s technological capacity from 1986 to 2007 reveals the evolution from analog to digital technologies, and the majority of the authors' technological memory has been in digital format since the early 2000s.
Abstract: We estimated the world’s technological capacity to store, communicate, and compute information, tracking 60 analog and digital technologies during the period from 1986 to 2007. In 2007, humankind was able to store 2.9 × 10 20 optimally compressed bytes, communicate almost 2 × 10 21 bytes, and carry out 6.4 × 10 18 instructions per second on general-purpose computers. General-purpose computing capacity grew at an annual rate of 58%. The world’s capacity for bidirectional telecommunication grew at 28% per year, closely followed by the increase in globally stored information (23%). Humankind’s capacity for unidirectional information diffusion through broadcasting channels has experienced comparatively modest annual growth (6%). Telecommunication has been dominated by digital technologies since 1990 (99.9% in digital format in 2007), and the majority of our technological memory has been in digital format since the early 2000s (94% digital in 2007).
1,450 citations