Compiler flags when profiling a build

[Guillaume Piolat]

On Sunday, 25 October 2020 at 14:47:50 UTC, Per Nordlöw wrote:
>
> Why not use dmd's own `-profile` flag? Is too intrusive on 
> performance? I've noticed a massive slow-down with about a 
> magnitude.

1. Because LDC doesn't have -profile and changing backends is an 
important an easy optimization.

2. Quoting 
https://en.wikipedia.org/wiki/Profiling_(computer_programming)#Data_granularity_in_profiler_types :

> In practice, sampling profilers can often provide a more 
> accurate picture of the target program's execution than other 
> approaches, as they are not as intrusive to the target program, 
> and thus don't have as many side effects (such as on memory 
> caches or instruction decoding pipelines). Also since they 
> don't affect the execution speed as much, they can detect 
> issues that would otherwise be hidden.