As you know, I changed a couple of workplaces during my career. Long story short, one interesting thing that I noticed in different companies is various models for multi-threaded programs (mostly for large embedded systems).

This article explains how to implement performance critical reference counting in C/C++ program, using atomic variables and gcc. Enjoy it. Read the article here.

Table of contents Introduction What reference counting needed for? This is how we will use atomic variables to count references to objects The naive approach The RCU approach Where atomic variables coming from? Conclusion IntroductionBACK TO TOC Lets say we have a data structure that manages objects and we would like to manipulate the data […]

Update 06/16/2009: On several occasions, commentators to this article pointed out that this post is somewhat incomplete. Therefore, before I continue, I would like to make some things clear. Before considering the code below, please note that spinlocks are totally useless on uni-processor computers. This is due to a nature of spinlocks, which I will […]

Continuing my previous post, I would like to talk about relatively new feature in glibc and pthreads in particular. I am talking about spinlocks.

Recently I ran into few pieces of code here and there that assumed that int is an atomic type. I.e. when you modify value of the variable from two or more different threads at the same time, all of the changes you’ve made to the value will remain intact. But really, can you modify variables […]

Table of contents Introduction What reference counting needed for? This is how we will use atomic variables to count references to objects The naive approach The RCU approach Where atomic variables coming from? Conclusion Introduction tcpdump uses Invocation Simple filtering Reading tcpdump‘s output Invocation continued Choosing an interface Turning off name resolution Limiting number of […]