I don't think anyone would have any problems if you did it, no? I've done many things because they annoyed *me*. The question is, if it is worth it. For someone that just rebuilds ISAs all the time, I can imagine that it is worth it even if it did increase overall build time slightly. I think it's a fair trade-off to have a neutral build time or even a slight increase if it meant that you could get your machine to work on a file in a better way. My guess is that the major concern was compiling the same thing many time. One thing to consider when you're doing this is to use precompiled headers. I'm pretty sure that gcc supports them and they could in this instance make a difference. (Of course, we need to make it work without PCH).
Nate On Wed, Jan 19, 2011 at 2:21 AM, Gabe Black <[email protected]> wrote: > 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. > > Gabe > _______________________________________________ > m5-dev mailing list > [email protected] > http://m5sim.org/mailman/listinfo/m5-dev > > _______________________________________________ m5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/m5-dev
