(See “ The Horizon of Predictability” for more information about this.)Ģ. Don’t add items that are uncertain or will be done far in the future. Keep the Work Queue small by recording only high priority items that need to be done immediately. The time spent on creating this initial version should be minimized using three techniques:ġ. The initial creation of this Work Queue is a simple process: based on the goals to be attained, and based on an other factors that are relevent, the Product Owner drafts an initial version of the Work Queue. The Product Owner is responsible for creating and managing the Work Queue. If iterations are being used to plan work, then the Work Queue is updated every iteration. The number of items on the list that are being worked on simultaneously will depend on the capacity of the people doing the work. As an item on the list is completed, it is removed from the Work Queue. One or more of the items from the top of the Work Queue are selected to be worked on. The Work Queue is constantly maintained by the Queue Master so that it maintains the above mentioned qualities. Ideally, it is created before work towards the goal is started, but often Agile Work will be adopted for an ongoing effort, in which case work has already started. The Work Queue is initially created after the overall goal is determined. The place of the Work Queue in the process is very simple. The person holding the Product Owner role manages the list. All items on the Work Queue contribute directly to an overall goal. The list is prioritized so that the item on the top of the list is the single most important thing to get done, with items below that being successively lower priority.
#WORK QUEUE HOW TO#
The list consists of brief descriptions of what to deliver, not how to do it. The Work Queue is a list of work to be done by a person, team, organization or community. This article details the use of the Work Queue. The Work Queue is like a carefully managed To-Do list. This is very similar to the Scrum Product Backlog but there are some differences too. Thread 4549251072, loop 0 - waiting for item.Agile Work requires only a very small number of simple “artifacts”. Thread 4547428352, loop 0 - waiting for item. If you run the test application with an argument of 3 this is what the output will look like: $.
#WORK QUEUE CODE#
Note that you must get the Thread class code before trying to make wqueue. You can build the test application by going into the wqueue directory and running make. The main() routine, work item class and consumer thread class definitions are all contained in the main.cpp file. You can get the source code for the project from Github –.
After the specified number of iterations the producer will wait for a Ctrl-C to end the program. Using namespace std template class wqueue Įach time through the main loop, 3 items are placed in the queue. To serialize access to the queue and enable the producer thread to signal the consumer threads that work items are available for processing the queue class will be instrumented with a Pthread mutex and condition variable – defined by the m_mutex and m_condv member variables respectively in this case. Lists provide methods for adding work items to the tail of the queue and removing items from the head of the queue – first in first out (FIFO) – in constant time. It is based on the list class from the Standard C++ Library. The work queue class wqueue will be defined in the file wqueue.h. These steps are repreated continually for the lifetime of the application. If none are available the consumer waits for the producer to add items to the queue.
If there are one ore more work items on the queue the consumer removes one and processes it. When a consumer thread runs it checks the number of items on the queue. For the work wqueue class in this article we’ll use one producer thread and two consumer threads. One approach to multithreading is the producer-consumer model where one thread – the producer – places work items in a queue and one or more consumer threads waits for and removes the items to process. In this article I’ll discuss the design of a work queue class implemented in C++ that can be used with Thread class objects to easily build a multithreaded application. Queues are good devices for transferring work items from one thread to another. The next step to building a multithreaded application is to devise a means to distribute tasks between threads so they can be processed concurrently. In a previous blog Java Style Thread Class in C++ I discussed how to develop a C++ class that enables you to create Pthread based objects that resemble Java threads.
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