* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 26 Jun 2013 11:22:48 +0200 Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > > except that on 32 TB > > systems we don't spend ~2 hours initializing 8,589,934,592 page heads. > > That's about a million a second which is crazy slow - even my > prehistoric desktop is 100x faster than that. > > Where's all this time actually being spent? See the earlier part of the thread - apparently it's spent initializing the page heads - remote NUMA node misses from a single boot CPU, going across a zillion cross-connects? I guess there's some other low hanging fruits as well - so making this easier to profile would be nice. The profile posted was not really usable. Btw., NUMA locality would be another advantage of on-demand initialization: actual users of RAM tend to allocate node-local (especially on large clusters), so any overhead will be naturally lower. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
