Concur and C++ Futures

Speaker: Herb Sutter

Abstract:

Discussions of concurrency & C++ futures September 2006 meeting of the Northwest C++ Users Group.

Getting C++ Threads Right

Speaker: Hans Boehm

Abstract:

The advent of multicore processors has generated profound debate on the merits of writing parallel programs with threads and locks. Nonetheless, for many application domains, this remains the standard paradigm for writing parallel programs, and at the moment, there is no apparent universal replacement. And it is the focus of this talk.

Somewhat surprisingly, there are a number of often subtle, but generally fixable, industry-wide problems with current approaches to threads programming. We’ll focus on probably the most widely used environments, consisting of C or C++ with a standard threads library. Problems span the spectrum from system libraries through language implementations through supporting hardware. They get in the way both in that they often make it difficult to write 100% reliable multi-threaded software, and in that they confuse even the basics of the programming model, thus making it hard to teach. A surprising number of "experts" do not understand the basic rules. Arguably, these problems really need to be addressed to even allow a meaningful comparison to other parallel programming approaches.

Since solutions to these problems generally require a coordinated industry effort, we helped to persuade the C++ standards committee to address them by pursuing a coherent approach to threads in the next C++ standard. The talk will outline some of the proposed solutions, and give an update on this effort.

Machine Architecture: Things Your Programming Language Never Told You

Speaker: Herb Sutter

Abstract:

High-level languages insulate the programmer from the machine. That’s a wonderful thing — except when it obscures the answers to the fundamental questions of “What does the program do?” and “How much does it cost?” The C++/C#/Java programmer is less insulated than most, and still we find that programmers are consistently surprised at what simple code actually does and how expensive it can be — not because of any complexity of a language, but because of being unaware of the complexity of the machine on which the program actually runs. This talk examines the “real meanings” and “true costs” of the code we write and run especially on commodity and server systems, by delving into the performance effects of bandwidth vs. latency limitations, the ever-deepening memory hierarchy, the changing costs arising from the hardware concurrency explosion, memory model effects all the way from the compiler to the CPU to the chipset to the cache, and more — and what you can do about them.