[I work on Docker for Mac]<p>The early betas focussed on feature completeness rather than performance for filesystem sharing. In particular, we have implemented a new &quot;osxfs&quot; that implements bidirectional translation between Linux and OSX filesystems, including inotify&#x2F;FSEvents and uid&#x2F;guid mapping between the host and the container.  Getting the semantics right took a while, and all the recent betas have been steadily gaining in performance as we implement more optimisations in the data paths.<p>If you do spot any pathological &quot;spinning cases&quot; where a particular container operation appears to spiking the CPU more than it should be in, we&#x27;d like to know about it so we can fix it. Reproducible Dockerfiles on the Hub are particularly appreciated so that we can add them to the regression tests.