On 2018-05-21, Peter Hessler <[email protected]> wrote: > i386 and amd64 are different platforms, so of course you get different > packages. > > Within the same platform, all binaries that are built should run on all > possible members of that platform. > > So, code will be compiled WITHOUT AVX support, unless it can be detected > at runtime (e.g. mplayer/ffmpeg). I believe that firefox does not to > runtime detection, so firefox should not directly call AVX.
Firefox isn't a great example, the rust code targets p4 with sse2. > On 2018 May 21 (Mon) at 18:37:43 -0300 (-0300), Elias M. Mariani wrote: >:Hi, >:I understand that about the builds and packages. >:I will re write my question in another form: >:If I build, say, firefox on a i386 machine I get a package, and >:another if I build firefox on amd64, they differ. >:If I build firefox on an amd64 machine WITHOUT AVX support I get a >:package, if now I build firefox in an amd64 machine WITH AVX support, >:do I still get the same package ? >:(firefox is a random pick) You may be able to build some things with different compiler flags to use different cpu-specific instructions (-march, -mtune). If you have some very specific computation-heavy software that needs to be high performance then *maybe* it's worth looking into this. But in the general case you're going to waste far more time than you save just in compiling, let alone if you have to spend any extra time debugging.
