I know we've talked about this before, but another reason for breaking up ISA generated files occurred to me as I'm waiting for X86_SE to build. On a machine with a moderate amount of memory, compiling, say, 8 way parallel works just fine since the memory footprint fits and there's enough work for the CPUs to do. If you happen to hit 2 or 3 (or 4 or 5) of the monster ISA files, though, the memory requirements go up substantially and you could end up blowing out your memory. This has happened to me in the past, and I've end up swapping so bad I had to ssh in from another machine to kill the build since X stopped responding. Needless to say the build time suffers as well. By breaking these really big files into smaller chunks, the memory ceiling of builds stays at a reasonable level throughout. Otherwise if you hit that bottleneck, the only way to move past it is to reduce parallelism for the whole build which makes large parts of it suboptimal. Of course this all sounds nice but is a pain or at least a lot of work to implement, and there was a sentiment (which is quite possibly justified) that the shorter compile times * more compiles comes out in the wash. I think this issue, however, is harder to ignore and a good reason to give this more thought.
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