On Thursday 14 February 2008 21:25:59 Mike Travis wrote: > Christoph Lameter wrote: > > On Thu, 14 Feb 2008, Andi Kleen wrote: > > > >> You're saying the kernel should use these relative masks internally? > > > > There is just some thoughts about this. Did not have time to look into the > > details. Mike? > > There are a few places where the entire cpumask is not needed. For > example, in the area of core siblings on a node. There's a limit > to how many cores/threads can be on a node and the full 4k cpumask > is not needed. How this pertains to this new functionality I'm > not sure yet.
That would require that the BIOS enumerates the CPUs in a way that the cores of a socket are continuous. While that's usually true I don't think there's a guarantee. In theory they could be all scattered. Ok I theory Linux could remap later but that seems hardly worth the trouble. I would rather just use arrays of integers in this case with a reasonable fixed upper limit (e.g. 16 or 32 -- if there are ever >32 thread x86 CPUs presumably they will require an updated cpufreq driver too...) -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
