> > > > -static DEFINE_PER_CPU(struct rq, runqueues); > > +static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; > > Remember that this can consume up to (linesize-4 * NR_CPUS) bytes,
On x86 just the real possible map now -- that tends to be much smaller. There might be some other architectures who still allocate per cpu for all of NR_CPUs (or always set possible map to that), but those should be just fixed. > which is > rather a lot. We should have solved the problem of limited per cpu space in .22 at least with some patches by Jeremy. I also plan a few other changes the will use more per CPU memory again. > Remember also that the linesize on VSMP is 4k. > > And that putting a gap in the per-cpu memory like this will reduce its > overall cache-friendliness. When he avoids false sharing on remote wakeup it should be more cache friendly. > Need more convincing, please. Was this based on some benchmark where it showed? -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/