On Fri, Aug 12, 2016 at 12:23:29PM +1000, Dave Chinner wrote: > Christoph, maybe there's something we can do to only trigger > speculative prealloc growth checks if the new file size crosses the end of > the currently allocated block at the EOF. That would chop out a fair > chunk of the xfs_bmapi_read calls being done in this workload. I'm > not sure how much effort we should spend optimising this slow path, > though....
I can look at that, but indeed optimizing this patch seems a bit stupid. The other thing we could do is to optimize xfs_bmapi_read - even if it shouldn't be called this often it seems like it should waste a whole lot less CPU cycles.
