Shared Queue, Speculation, Circuits

Shared Queue Pattern

The shared queue pattern is found quite often in software applications involving the processing of multiple tasks. A centralized share queue is definitely one of the easier implementations. A common use of shared queue is with a thread pool. One concept is to allow the individual threads pull tasks directly from the queue. Another option is for a master thread to take responsibility for distributing the tasks to the threads for load balancing.

Although the examples in the paper used separate locks for put and take, I believe it is more common to use a single lock for the entire queue. Two locks might be overkill depending on the number threads working off the queue and the max size of the queue itself.


Speculation

I do wish the HTML lexer example was earlier in the paper. After getting through most of the paper, I recalled learning about speculation with branch prediction in a previous class. With branch prediction one path is speculatively chosen based on the past behavior of the program. This can be extended to speculatively execute both branches and terminate one of them when the result of the branch predicate is available.

I do want to go back and review this pattern again after the class discussion. I suspect there will be informative information discussed to help me gain a better understanding of this pattern.


Circuits Pattern

I can honestly say I had no idea what the Circuits Pattern entailed when reading the title. Even though this is not a Physics class, I thought it might have something to do with electronic circuits.

It is unfortunate I have not been professionally exposed to bit shifting as I might have had a more genuine appreciation for the examples of limited information presented in this paper. The md5 example was familiar and somewhat intriguing to see how it is really implemented. Looks like this might be another pattern I will revisit after the class discussion.