Study of : "SEDA: An Architecture for Well-Conditioned, Scalabel Internet Services" (1)

Abstract

We propose a new design for highly concurrent Internet services, which we call the staged event-driven architecture(SEDA). SEDA is intended to support massive concurrency demands and simplify the construction of well-conditioned servieces. In SEDA, applications consist of a network of event-driven stages connected by explicit queues. This architecture allows services to be well-conditioned to load, preventing resources from being overcommitted  when demand exceeds service capacity. SEDA makes use of a set of dynamic resource controllers to keep stages within their operating regime despite large fluctuations in load.  We describe several control mechanismsfor automatic tuning and load conditioning, including thread pool sizing, event batching, and apaptive load shedding. We present the SEDA design and an implementation of an Internet services platform based on this architecture. We evaluate the use of SEDA through two applications: a high-performance HTTP server and a pachet router for the Gnutella peer-to-peer file sharing network. These results show that SEDA applications exhibit higher performance than traditional service designs, and are robust to huge variations in load.

相关字的注解：

propose vt.计划, 建议, 向...提议, 求(婚) vi.打算, 求婚

concurrent n.同时发生的事件 adj.并发的, 协作的, 一致的

stage n.舞台, 戏剧, 活动场所, 发展的进程, 阶段或时期, 驿站 vt.上演, 筹备, 举行

intended adj.有意的, 故意的, 已经订婚的 n.已经订婚者

be intended to be  规定为, 确定为

massive adj.厚重的, 大块的, 魁伟的, 结实的

demand n.要求, 需求(量), 需要 v.要求, 需要, 要求知道, 查询

simplify vt.单一化, 简单化

conditioned adj.有条件的, 习惯于...的

consist of v.由...组成

explicit adj.外在的, 清楚的, 直率的, (租金等)直接付款的

queue n.行列, 长队, 队列 vi.排队, 排队等待

prevent v.防止, 预防

overcommit [计] 过量使用

exceed vt.超越, 胜过 vi.超过其他

capacity n.容量, 生产量, 容量, 智能, 才能, 能力, 接受力, 地位

regime n.政体, 政权, 政权制度

despite prep.不管, 尽管, 不论

fluctuation n.波动, 起伏

mechanism n.机械装置, 机构, 机制

tuning n.调谐, 调整, 调音

batching 定量, 计量

adaptive adj.适应的

shed vt.流出, 发散, 散发, 脱落, 脱皮, 摆脱 n.分水岭, 棚, 小屋, 工棚, 货棚 v.把...放入棚内, 流下

present n.赠品, 礼物, 现在, 瞄准 adj.现在的, 出席的, 当面的 vt.介绍, 引见, 给, 赠送, 上演, 提出, 呈现 vi.举枪瞄准

implementation n.执行

evaluate vt.评价, 估计, 求...的值 v.评价

performance  n.履行, 执行, 成绩, 性能, 表演, 演奏

exhibit vt.展出, 陈列 n.展览品, 陈列品, 展品 v.展示

traditional adj.传统的, 惯例的, 口传的, 传说的

robust adj.精力充沛的

variation n.变更, 变化, 变异, 变种, [音]变奏, 变调