On Sat, 25 Aug 2007, Andi Kleen wrote:
> On Fri, Aug 24, 2007 at 05:50:18PM -0700, Siddha, Suresh B wrote: > > On Fri, Aug 24, 2007 at 03:26:54PM -0700, [EMAIL PROTECTED] wrote: > > > Previous Intro: > > > > Thanks for doing this. > > > > > In x86_64 and i386 architectures most arrays that are sized > > > using NR_CPUS lay in local memory on node 0. Not only will most > > > (99%?) of the systems not use all the slots in these arrays, > > > particularly when NR_CPUS is increased to accommodate future > > > very high cpu count systems, but a number of cache lines are > > > passed unnecessarily on the system bus when these arrays are > > > referenced by cpus on other nodes. > > > > Can we move cpuinfo_x86 also to per cpu area? Though critical run > > I worry how much impact that would be? boot_cpu_data is quite > widely used. > I looked at this and it would be a big memory savings. But I haven't yet analyzed the various accesses to verify that we can cleanly move the structure, and that we don't suffer a bunch of tlb misses because accesses are primarily from node 0. More info soon. Thanks, Mike - 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/
