performance

Using Parallel Without a Clue: 90x Performance Loss Instead of 8x Gain—“No Bugs” Hare

Be careful.

Using Parallel <algorithm> Without a Clue: 90x Performance Loss Instead of 8x Gain

by "No Bugs" Hare

From the article:

With C++17 supporting1 parallel versions of the std:: algorithms, there are quite a few people saying “hey, it became really simple to write parallel code!”.

Just as one example, [MSDN] wrote: “Only a few years ago, writing parallel code in C++ was a domain of the experts.” (implying that these days, to write parallel code, you don’t need to be an expert anymore).

Inquisitive hare:
“I made an experiment which demonstrates Big Fat Dangers(tm) of implying that parallelization can be made as simple as just adding a policy parameter to your std:: call.
I always had my extremely strong suspicions about this position being deadly wrong, but recently I made an experiment which demonstrates Big Fat Dangers(tm) of implying that parallelization can be made as simple as just adding a policy parameter to your std:: call...

My Little (String) Optimization, Part 2—Jordan Rose

Performance!

My Little (String) Optimization, Part 2

by Jordan Rose

From the article:

Previously, I talked about how Clang is smart enough to optimize a series of comparisons against constant strings in C++ by starting out with a switch on the length. I left off with the idea that while this is good, you might be able to do better if your strings have a unique character at a certain offset. Today we’re going to see what that looks like.

HPX V1.1 released—STE||AR Group

The STE||AR Group has released V1.0 of HPX -- A C++ Standard library for parallelism and concurrency.

HPX V1.1 Released

The newest version of HPX (V1.1) is now available for download! Please see here for the release notes.

HPX exposes an API fully conforming to the concurrency related parts of the C++11/C++14/C++17 standards, extended and applied to distributed and heterogeneous computing, and aligned with the ongoing standardization discussions.

    HPX is a general purpose parallel C++ runtime system for applications of any scale. It implements all of the related facilities as defined by the C++ Standard. As of this writing, HPX provides the only widely available open-source implementation of the new C++17 parallel algorithms. Additionally, HPX implements functionalities proposed as part of the ongoing C++ standardization process, such as large parts of the C++ Concurrency TS, task blocks, data-parallel algorithms, executors, index-based parallel for loops, and many more. It also extends the existing C++ Standard APIs to the distributed case (e.g. compute clusters) and for heterogeneous systems (e.g. GPUs).
    HPX seamlessly enables a new asynchronous C++ Standard Programming Model which tends to improve the parallel efficiency of our applications and helps reduce complexities usually associated with concurrency

Do compilers take inline as a hint?—Simon Brand

Isn't that a good question?

Do compilers take inline as a hint?

by Simon Brand

From the article:

If you’ve spent any time in C or C++ communities online, you’ve probably seen someone say this:

inline used to be a hint for compilers to inline the definition, but no compilers actually take that into account any more.

You shouldn’t believe everything you see on the internet...