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.

相關字的注解：

propose vt.計劃, 建議, 向...提議, 求(婚) vi.打算, 求婚

concurrent n.同時發生的事件 adj.并發的, 協作的, 一緻的

stage n.舞台, 戲劇, 活動場所, 發展的程序, 階段或時期, 驿站 vt.上演, 籌備, 舉行

intended adj.有意的, 故意的, 已經訂婚的 n.已經訂婚者

be intended to be  規定為, 确定為

massive adj.厚重的, 大塊的, 魁偉的, 結實的

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

simplify vt.單一化, 簡單化

conditioned adj.有條件的, 習慣于...的

consist of v.由...組成

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

queue n.行列, 長隊, 隊列 vi.排隊, 排隊等待

prevent v.防止, 預防

overcommit [計] 過量使用

exceed vt.超越, 勝過 vi.超過其他

capacity n.容量, 生産量, 容量, 智能, 才能, 能力, 接受力, 地位

regime n.政體, 政權, 政權制度

despite prep.不管, 盡管, 不論

fluctuation n.波動, 起伏

mechanism n.機械裝置, 機構, 機制

tuning n.調諧, 調整, 調音

batching 定量, 計量

adaptive adj.适應的

shed vt.流出, 發散, 散發, 脫落, 脫皮, 擺脫 n.分水嶺, 棚, 小屋, 工棚, 貨棚 v.把...放入棚内, 流下

present n.贈品, 禮物, 現在, 瞄準 adj.現在的, 出席的, 當面的 vt.介紹, 引見, 給, 贈送, 上演, 提出, 呈現 vi.舉槍瞄準

implementation n.執行

evaluate vt.評價, 估計, 求...的值 v.評價

performance  n.履行, 執行, 成績, 性能, 表演, 演奏

exhibit vt.展出, 陳列 n.展覽品, 陳列品, 展品 v.展示

traditional adj.傳統的, 慣例的, 口傳的, 傳說的

robust adj.精力充沛的

variation n.變更, 變化, 變異, 變種, [音]變奏, 變調