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SEDA - The Staged Event-Driven Architecture
Matt Welsh,
mdw@cs.berkeley.edu |
The Staged Event-Driven Architecture (SEDA) is a new design for building scalable Internet services. SEDA has three major goals:
SEDA decomposes a complex, event-driven application into a set of stages connected by queues. This design avoids the high overhead associated with thread-based concurrency models, and decouples event and thread scheduling from application logic. SEDA enables services to be well-conditioned to load, preventing resources from being overcommitted when demand exceeds service capacity. Decomposing services into a set of stages also enables modularity and code reuse, as well as the development of debugging tools for complex event-driven applications.
The SEDA project currently consists of two software packages.
Sandstorm provides a rich set of interfaces for developing SEDA-based Internet services, and uses the NBIO library (or, alternately, the JDK 1.4 java.nio package) for nonblocking I/O operations. NBIO can also be used by itself, without Sandstorm.
The SEDA home page is http://www.cs.berkeley.edu/~mdw/proj/seda. This includes links to this source code release as well as papers, talks, and other background material.
For mailing list info, releases, bug tracking, etc. see the SEDA SourceForge project page at http://seda.sourceforge.net.
All of the software in this tree is covered by the following Open Source license.
Copyright (c) 2002 by The Regents of the University of California All rights reserved.
Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without written agreement is hereby granted, provided that the above copyright notice and the following two paragraphs appear in all copies of this software.
IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.