On Fri, Mar 13, 2020 at 05:09:52PM -0400, Josef Bacik wrote: > In debugging Zygo's huge commit delays I noticed we were burning a bunch of time > doing READA in cases where we don't need to. The way READA works in btrfs is > we'll load up adjacent nodes and leaves as we walk down. This is useful for > operations where we're going to be reading sequentially across the tree. > > But for delayed refs we're looking up one bytenr, and then another one which > could be elsewhere in the tree. With large enough extent trees this results in > a lot of unneeded latency. > > The same applies to build_backref_tree, but that's even worse because we're > looking up backrefs, which are essentially randomly spread out across the extent > root. Thanks, Makes sense, I'll add it to misc-next. Thanks.
