On Mon, Aug 12, 2024 at 03:38:43PM +0200, Christoph Hellwig wrote: > On Thu, Aug 08, 2024 at 04:04:03PM -0700, Luis Chamberlain wrote: > > This is not just about mTHP uses though, this can also affect buffered IO and > > direct IO patterns as well and this needs to be considered and tested as well. > > Not sure what the above is supposed to mean. Besides small tweaks > to very low-level helpers the changes are entirely in the direct I/O > path, and they optimize that path for folios larger than PAGE_SIZE. Which was my expectation as well. > > I've given this a spin on top of of the LBS patches [0] and used the LBS > > patches as a baseline. The good news is I see a considerable amount of > > larger IOs for buffered IO and direct IO, however for buffered IO there > > is an increase on unalignenment to the target filesystem block size and > > that can affect performance. > > Compared to what? There is nothing in the series here changing buffered > I/O patterns. What do you compare? If this series changes buffered > I/O patterns that is very well hidden and accidental, so we need to > bisect which patch does it and figure out why, but it would surprise me > a lot. The comparison was the without the patches Vs with the patches on the same fio run with buffered IO. I'll re-test more times and bisect. Thanks, Luis
