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iunknown:
909601686 写道我理解下来,之所以使用奇数应该不仅仅是 ...
以两军问题为背景来演绎Basic Paxos -
909601686:
我理解下来,之所以使用奇数应该不仅仅是为了判断谁赢。而是这样就 ...
以两军问题为背景来演绎Basic Paxos -
feclipse:
you are my hero! 看了你的图示之后,我的理解 ...
以两军问题为背景来演绎Basic Paxos -
lcc0739:
相当好!通俗易懂,看了好几篇paxos只有你这个最深入浅出!
以两军问题为背景来演绎Basic Paxos -
iunknown:
tangfu 写道hi,问一下,博主提供的库与pb兼容么,比如 ...
一个轻量的 wire format 解释器(google protobuf 的二进制格式)
An Architecture for Highly Concurrent Well-Conditioned Internet Services.pdf
SEDA 项目的相关论文
Page26
The use of helper processes in Flash and Harvest underscores the occasional need for an event-driven system to resort to blocking operations, either to reduce complexity or to make use of legacy interfaces and libraries.
Most event-driven systems develop ad hoc mechanisms for integrating blocking code into the service, requiring careful management of thread/process resources to perform the dispatch.
Page27
An important limitation of this model is that it requires event-handling code to be short and run to completion, to avoid stalling the event-processing threads, and to ensure fairness across a large number of requests.
Flash, Harvest, and other systems address this challenge using separate threads or processes to perform long-running operations asynchronously.
Page29
One of the starting points of the SEDA design was the I/O core framework [54] used by the Ninja system at UC Berkeley.
In the Ninja I/O core, a limited number of threads is used to process requests flowing through the system, and blocking socket and disk I/O operations are converted into asynchronous, split-phase operations using a dedicated pool of threads, similar to the Flash use of helper processes.
Page36
The approach taken in SEDA can be thought of as a middleware layer between the application and the operating system, monitoring application behavior and effecting control over resource consumption.
Page52
First, the use of threads relaxes the constraint that all event-processing code be non-blocking, allowing an event handler to block or be preempted if necessary. In a traditional event-driven system, all blocking operations must explicitly capture the state of the computation and restore it when the operation completes. In SEDA, threads act as implicit continuations, automatically capturing the execution state across blocking operations.
Page54
A SEDA application is constructed as a network of stages, connected by event queues.
A rejected enqueue operation is signaled immediately to the originating stage, for example, by returning an error code. Enqueue rejection acts as an explicit overload signal to applications and should be used by the service to adapt behavior in some way.
Page56
Stages are therefore composed using a protocol, rather than merely type-matching of function arguments and return values, admitting a flexible range of composition policies.
Page61
In Apache, the request queue is implemented using the accept() system call; as discussed previously, this can lead to dropped TCP connections if the listen queue fills up.
A Design Framework and a Salable Storage Platform to Simplify Internet Service Construction.pdf
Ninja 项目的相关论文
Page35
In particular, the programmer doesn't worry about scheduling, as the thread scheduler handles this, or per-task state management, as the compiler transparently places task state on thread stacks in the form of automatic variables.
Programmers are comfortable coding in the sequential programming style of threads, and programmer tools (such as debuggers and thread-safe class libraries ) are relatively mature.
Page39
Unlike a threaded server, with an event-driven system, the programmer must explicitly manage all tasks' state. Partial state associated with a task must be bundled into a self-contained object, and stored in a table indexed by a unique identifier associated with the task. When the program thread pulls an event off of the queue, it associates the event with its task, retrieves this task's state, and invokes the correct task stage with the event and task state as arguments.
Page42
An opportunity that the explicit event queue enables is the ability for the system to perform admission control. If the system is saturated, the event queue will begin to grow, increasing task latency. The system can shed load and reduce latency by simply dropping tasks from this queue, optionally sending error messages back to the sender. Queues in an event-driven system are thus a useful mechanism which exposes resources and the ability to impose resource management policies to the programmer and program.
Page42
We belive that the design space for concurrent servers is not limited to just threaded and event-driven systems, but rather that there is a spectrum between these extremes, and it is possible to build hybrid systems that can exploit the advantages of both programming models. For example, a hybrid system can expose a threaded programming style to programmers, while simultaneously exposing an event queue, and limiting the number of concurrently executing threads so as to prevent performance degradation.
Page49
The wrap pattern placas a queue in front of a stage, and assigns a bounded number of threads to the stage in order to process tasks that arrive on its queue.
The queue serves to condition the stage to load; excess work that cannot be absorbed by the stage's threads is buffered in the queue, increasing latency through the stage.
Page61
This queue/thread combination is the result of applying the "wrap" pattern with a minimally sized thread pool.
Page156
A known weakness of event-driven models is the increased difficulty of debugging them. The control flow of a task in an event-driven model is no longer equivalent to the control flow of a single thread, since tasks can span threads by crossing thread boundaries, or they can have no execution context at all while sitting idle in queues.
Traditional debuggers only allow programmers to inspect variable state and to trace the execution of threads; such debuggers have no notion of causality from events, and accordingly it is impossible for them to provide an event tracing facility.
SEDA 项目的相关论文
Page26
The use of helper processes in Flash and Harvest underscores the occasional need for an event-driven system to resort to blocking operations, either to reduce complexity or to make use of legacy interfaces and libraries.
Most event-driven systems develop ad hoc mechanisms for integrating blocking code into the service, requiring careful management of thread/process resources to perform the dispatch.
Page27
An important limitation of this model is that it requires event-handling code to be short and run to completion, to avoid stalling the event-processing threads, and to ensure fairness across a large number of requests.
Flash, Harvest, and other systems address this challenge using separate threads or processes to perform long-running operations asynchronously.
Page29
One of the starting points of the SEDA design was the I/O core framework [54] used by the Ninja system at UC Berkeley.
In the Ninja I/O core, a limited number of threads is used to process requests flowing through the system, and blocking socket and disk I/O operations are converted into asynchronous, split-phase operations using a dedicated pool of threads, similar to the Flash use of helper processes.
Page36
The approach taken in SEDA can be thought of as a middleware layer between the application and the operating system, monitoring application behavior and effecting control over resource consumption.
Page52
First, the use of threads relaxes the constraint that all event-processing code be non-blocking, allowing an event handler to block or be preempted if necessary. In a traditional event-driven system, all blocking operations must explicitly capture the state of the computation and restore it when the operation completes. In SEDA, threads act as implicit continuations, automatically capturing the execution state across blocking operations.
Page54
A SEDA application is constructed as a network of stages, connected by event queues.
A rejected enqueue operation is signaled immediately to the originating stage, for example, by returning an error code. Enqueue rejection acts as an explicit overload signal to applications and should be used by the service to adapt behavior in some way.
Page56
Stages are therefore composed using a protocol, rather than merely type-matching of function arguments and return values, admitting a flexible range of composition policies.
Page61
In Apache, the request queue is implemented using the accept() system call; as discussed previously, this can lead to dropped TCP connections if the listen queue fills up.
A Design Framework and a Salable Storage Platform to Simplify Internet Service Construction.pdf
Ninja 项目的相关论文
Page35
In particular, the programmer doesn't worry about scheduling, as the thread scheduler handles this, or per-task state management, as the compiler transparently places task state on thread stacks in the form of automatic variables.
Programmers are comfortable coding in the sequential programming style of threads, and programmer tools (such as debuggers and thread-safe class libraries ) are relatively mature.
Page39
Unlike a threaded server, with an event-driven system, the programmer must explicitly manage all tasks' state. Partial state associated with a task must be bundled into a self-contained object, and stored in a table indexed by a unique identifier associated with the task. When the program thread pulls an event off of the queue, it associates the event with its task, retrieves this task's state, and invokes the correct task stage with the event and task state as arguments.
Page42
An opportunity that the explicit event queue enables is the ability for the system to perform admission control. If the system is saturated, the event queue will begin to grow, increasing task latency. The system can shed load and reduce latency by simply dropping tasks from this queue, optionally sending error messages back to the sender. Queues in an event-driven system are thus a useful mechanism which exposes resources and the ability to impose resource management policies to the programmer and program.
Page42
We belive that the design space for concurrent servers is not limited to just threaded and event-driven systems, but rather that there is a spectrum between these extremes, and it is possible to build hybrid systems that can exploit the advantages of both programming models. For example, a hybrid system can expose a threaded programming style to programmers, while simultaneously exposing an event queue, and limiting the number of concurrently executing threads so as to prevent performance degradation.
Page49
The wrap pattern placas a queue in front of a stage, and assigns a bounded number of threads to the stage in order to process tasks that arrive on its queue.
The queue serves to condition the stage to load; excess work that cannot be absorbed by the stage's threads is buffered in the queue, increasing latency through the stage.
Page61
This queue/thread combination is the result of applying the "wrap" pattern with a minimally sized thread pool.
Page156
A known weakness of event-driven models is the increased difficulty of debugging them. The control flow of a task in an event-driven model is no longer equivalent to the control flow of a single thread, since tasks can span threads by crossing thread boundaries, or they can have no execution context at all while sitting idle in queues.
Traditional debuggers only allow programmers to inspect variable state and to trace the execution of threads; such debuggers have no notion of causality from events, and accordingly it is impossible for them to provide an event tracing facility.
发表评论
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以两军问题为背景来演绎Basic Paxos
2015-09-28 10:28 19181背景 在计算机通信理 ... -
自动化解决编译依赖问题
2010-12-04 14:02 3726一个用 c++ 实现的系统,过于庞大,依赖很复杂,还要变化很频 ... -
调试堆栈错乱的问题
2010-07-15 00:57 2581如果没有简单的重现办法,或者只是偶尔出现的话,可以通过 gli ... -
让设置 suid 的程序也产生 coredump
2010-05-11 11:24 2640被 suid 的程序要产生 coredump 文件,还需要额外 ... -
[zz]What does anon mean for pmap?
2010-02-26 21:12 4925http://stackoverflow.com/questi ... -
[zz]Troubleshooting Memory Usage
2010-01-13 21:05 1241http://rimuhosting.com/howto/me ... -
Half-Sync/Half-Async 和 Leader/Follower 模式的实现代码
2009-12-27 13:33 3178把之前发表过的一篇文 ... -
vc6 设置 pre-build 步骤
2009-11-06 22:52 1483把 spdatapickle 移植到 win32 平台,使用 ... -
socat
2009-10-28 23:11 1350socat 类似 telnet ,但是支持多种协议。 比如要 ... -
一个用于快速定位 C/C++ 函数返回位置的 macro
2009-09-28 23:11 1900这个 macro 是这样的 #define return ... -
使用 gettimeofday 来测量执行时间存在的问题
2009-08-01 17:25 5329之前一直使用 cprof 来分 ... -
[zz]Tokyo Cabinet Table Engine
2009-07-05 22:26 1386Sounds impressive and cool. I w ... -
[zz]Tokyo Cabinet Observations
2009-05-05 17:41 1406http://parand.com/say/index.php ... -
[zz]Save SQLite memory database to file
2009-04-25 15:45 3142http://itsystementwicklung.de/p ... -
SpamAssassin, spf, greylist, dnsbl 相关的 milter 编译安装
2009-04-05 14:15 1635首先,如果系统中没有 libmilter.a 库,那么下载 s ... -
milter client 的实现
2009-03-28 19:38 1206在浏览了 milter 的协议描述和具体的实现之后,决定自己动 ... -
[zz]break when opening certain file
2009-02-16 17:38 1154http://www.nabble.com/break-whe ... -
linux inotify 通知信息不包括 user 和 process 的原因
2008-10-09 16:59 1415http://groups.google.com/group/ ... -
在 SPServer 中集成 IOCP 和 SSL
2008-06-20 22:27 3388打算把 Windows 的 SSPI 集成到 SPServer ... -
Reasons for threading
2008-06-11 20:49 1231http://www.sagemath.org:9001/Gl ...
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