On Wed, Aug 14, 2013 at 01:50:02PM -0700, Dave Hansen wrote: > > Would a plain old fallocate() do the trick, or does it actually need > zeros written to it? It would be better to write zeros to it, so we aren't measuring the cost of the unwritten->written conversion. We could do a different test where at the end of each while loop, we truncate the file and then do an fallocate, at which point we could be measuring the scalability of the unwritten->written conversion as well as the write page fault. And that might be a useful thing to do at some point. But I'd suggest focusing on just the write page fault first, and then once we're sure we've improved the scalability of that micro-operation as much as possible, we can expand our scalability testing to include either writing into fallocated space, or doing extending writes. Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html