Cool VL Viewer forum

I was wandering through the buildlinux.sh. I noticed it will accept a 'tune' arg which enables a couple of compile options, if the CPU supports them. My rig's CPU now supports the options that are being grep'd ('avx' and 'cx16'). I have done some minimal 'testing' (i.e. is frame rate better/worse, CPU utilization, etc) with both the precompiled version from sldev.free.fr and my own build using --tune. I haven't noticed much of a difference but I'm pretty sure I wouldn't know what to check. I have tried to discern what those options provide and it seems like they would be things that would give benefit. Would there be any recommendation to build myself with the --tune arg, if my CPU supports the options, or is it not really of much benefit?

If you build the viewer for yourself, then there can only be some benefit in using the --tune option. However the benefit is very minor and most likely unnoticeable in most situations.

Basically, and for Core-i5/7 CPUs, the compiler will favour AVX operations over SSE2 ones in the generated code, but the viewer does not spend its time performing such operations either...

For other (older) CPUs the gain could theoretically be slightly higher, since the compiler will be invoked with the -mtune=native option, which might also take into account some instructions and data alignment rules, that may lead to faster execution on some processors; but here again, the gain will be quite minor (don't expect anything better than 1% or so in speed gain).

It will be interesting to see what happens with newer CPUs (e.g. the Ryzen), once new gcc/llvm-clang versions will take them into account, and provided you compile the viewer with one such new compiler version...

PS: I'll change the buildlinux.sh to use only "-mtune=native" (instead of "-mtune=corei7-avx -mavx" for Core-i5/7), since that option already includes all proper tunes for both existing (with current compiler versions) and future (with future compiler versions) CPUs.

Thanks for the explanation. Your indication that the benefit would be slight, aligns with my observations. I guess it's then just a matter of preference whether I wish to build myself or not.