Open Radar

 
When using iCloud Drive on a FileVault-enabled machine, I noticed that after importing a few GB of files into iCloud Drive that the process 'bird' and, on occasion, 'cloudd' were running a very high CPU usage, especially after a file change, addition, or deletion. 

This problem is furthered by the fact that these files can't simply be deleted as a whole directory on the iCloud Drive interface on iCloud.com, which repeatedly generates errors ("Could not delete this item...") when deleting apparently duplicate files that iCloud Drive has created whilst syncing. 

When I attempted to delete these directories from my iPhone (Under Settings > General > Usage > iCloud Manage Storage > Other Documents, I was greeted with a  similar error to the one I experienced on iCloud.com. ("Deletion of an item has failed. Please try again later.") However, I noticed that the duplicate files I observed on iCloud.com which were suffixed with " 2", now said "Encrypted File", leading me to believe that this is a FileVault-related issue as well.

Steps to Reproduce:
Use iCloud Drive on a FileVault-enabled machine. Attempt syncing of a large set of files, say a Git directory, to Drive. 

Expected Results:
Files sync smoothly in the background without overwhelming the resources of a MacBook Pro (Retina, 13-inch, late 2013). 

Actual Results:
Files sync at a sluggish pace (not that there is a progress indicator, but I repeatedly tried to view files on iCloud.com and saw how slowly they synced). Processes "bird" and "cloudd" max out CPU.

Configuration:
FileVault and iCloud Drive configured and enabled.
MacBook Pro (Retina, 13-inch, late 2013)
OS X build 14A379b