>> > Anticipatory prefaulting raises the highest fault rate obtainable >> > three-fold >> > through gang scheduling faults but may allocate some pages to a task that >> > are >> > not needed. >> >> IIRC that costed more than it saved, at least for forky workloads like a >> kernel compile - extra cost in zap_pte_range etc. If things have changed >> substantially in that path, I guess we could run the numbers again - has >> been a couple of years. > > Right. The costs come about through wrong anticipations installing useless > mappings. The patches that I posted have this feature off by default. Gang > scheduling can be enabled by modifying a value in /proc. But I guess the > approach is essentially dead unless others want this feature too. The > current page fault scalability approach should be fine for a couple of > years and who knows what direction mmu technology has taken then.
It would seem to depends on the locality of reference in the affected files. Which implies to me that the locality of libc, etc probably sucks, though we had a simple debug patch somewhere to print out a bitmap of which pages are faulted in and which are not ... was somewhere, I'll see if I can find it. M. - 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/
