Do programmers need to learn to program for multi-core?
Much has been written on the inability of the need for future applications to take advantage of dual-core and multi-core systems. I think most of it is hogwash.
Intel is a big proponent of the argument for more parallel-processing tools for programmers. This is no big surprise – Moore’s law has flattened out for the current generation of processors. They are expanding outwards to multiple cores now, no longer upwards to higher CPU speeds. Intel is understandably terrified that their PC CPU market demand is going to dry up. Its all marketing.
I prefer to look at reality.
Looking at whats running on my system, these are the some threading stats:
- Firefox – 18 threads
- Outlook – 31 threads
- Perforce P4V – 8 threads
- Custom .NET application – 13 threads
Seems like plenty of threading goodness is already going on.
Taking the example of the custom .NET application, there is a very noticeable performance hit when I run it within a virtual machine. I attribute this to the virtual environment only making use of a single processing core. Those 13 threads have to fight over the single processor. In addition, the .NET runtime (garbage collection etc) is highly concurrent – when running on a single-processor environment, it is crippled.
I am not arguing that all application threads are particularly busy. Truth be told, of the 13 threads, only one, sometimes 2-3 are ever particularly busy. I’m just saying that there are as many threads as are necessary to get the job done. As programmers, we need not care at all about multi-core, except where there is some advantage to be had in using it.
Applications are written do as many simultaneous things as the user expects. It has nothing to do with multi-core as to whether there are multiple threads – it has to do with what the user expects and what the application needs to do to meet those expectations.
Multiple CPUs are like RAM – you will never have enough for tomorrow’s needs. Heck, you can barely run Vista without a dual-core machine – the OS itself has too much going on to leave enough over for decent performance. Multi-core PCs are here to stay, but as programmers it is simply a case of “nothing to see here – move along”.
