On Sunday, 29 December 2013 at 13:46:07 UTC, Dicebot wrote:
This is not true. Assuming skilled use and same compiler backend those are equally performant. D lacks some low-level control C has (which is important for embedded) but it is not directly related to performance.
That low-level control also matters for performance, when you have hard deadlines. E.g. when the GC kicks in, it not only hogs all the threads that participate in GC, it also trash the caches unless you have a GC implementation that bypasses the caches. Sustained trashing of caches is bad.
C has low-level, low resource usage defaults. While you can do the same in some other languages they tend to default to more expensive use patterns. Like D defaults to stuff like GC and thread-local-storage. Defaults affect library design, which in turn affect performance. (thread local storage requires either an extra indirection through a register or multiple kernel level page tables per process)
