On Tue, 6 Apr 2010, Andrea Arcangeli wrote: > > Some performance result: Quite frankly, these "performance results" seem to be basically dishonest. Judging by your numbers, the big win is apparently pre-populating the page tables, the "tlb miss" you quote seem to be almost in the noise. IOW, we have memset page fault 1566023 vs memset page fault 2182476 looking like a major performance advantage, but then the actual usage is much less noticeable. IOW, how much of the performance advantage would we get from a _much_ simpler patch to just much more aggressively pre-populate the page tables (especially for just anonymous pages, I assume) or even just fault pages in several at a time when you have lots of memory? In particular, when you quote 6% improvement for a kernel compile, your own numbers make seriously wonder how many percentage points you'd get from just faulting in 8 pages at a time when you have lots of memory free, and use a single 3-order allocation to get those eight pages? Would that already shrink the difference between those "memset page faults" by a factor of eight? See what I'm saying? Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>