No DEBUG log even enable it by -l DEBUG

[wangyoucao577]

When I want to see some DEBUG log from OSRM(e.g. osrm-extract, etc), I found that there's nothing output even I passed in -l DEBUG.

osrm-backend/src/util/log.cpp

Lines 128 to 131 in 0050f5a

	case logDEBUG:
	#ifdef NDEBUG
	break;
	#endif

After check codes, I found that it will only be enabled by build with debug type in compiling time and pass in -l DEBUG in runtime. It's not a good idea for debugging. People also may want to see more logs for investigating some issues with release binary.

[wangyoucao577]

Refer to Project-OSRM#3427 (comment), disable debug log at compile time is mostly for performance.

[wangyoucao577]

I also did some performance benchmark for remove compile time debug log control, see Project-OSRM#3427 (comment)