Parallel for implementation [3]: Output

In the previous two installments I’ve tried to give a little insight into how OmniThreadLibrary’s Parallel ForEach is implemented (part 1 – Overview, part 2 – Input). Today I will conclude this short series with the description of output ordering – or what is know in the OTL as the .PreserveOutput modifier.

Ordering is usually used together with the .Into modifier. The reason lies in the integration between the Parallel infrastructure and your parallel code (the one that is executing as Parallel.ForEach payload). In the “normal” foreach statement, output from this parallel payload is not defined. You are allowed to do whatever in the foreach, to generate any output (in case you need it) but Parallel will know nothing about that. Therefore, the OTL has no ability to preserver any ordering because – at least from the viewpoint of the library – the parallelized code is producing no output.

OmniThreadLibrary Down Under

I’m very excited to announce that OmniThreadLibrary will appear before the Australian public in this year’s ADUG Symposium!

This year’s symposium will happen in Melbourne on 24th and in Sydney on 25th of March.

The title of my presentation will be “Getting full speed with Delphi?” and will cover multithreading programming and high-level OmniThreadLibrary stuff.

Getting full speed with Delphi
(Why single threaded is not good enough?)

In the last few years, the traditional approach to speeding up programs ("We'll just wait for the next generation of hardware.") doesn't work anymore.

In this talk, we'll see why Delphi programs use only 12.5 % CPU on a modern machine and what we can do about it.

The session will show you how to make murky waters of multithreading accessible to every Delphi developer with the help of open source OmniThreadLibrary.

In case you want to meet with me and discuss multithreading programming (or anything else, including life, universe and everything), I’ll be available before the Melbourne and after the Sydney event.

How to crash Delphi compiler in four easy steps

Step one

Start Delphi XE.

Step Two

Create simple project.