Looks like #7473 is related. According to discussion in #7473 `getModificationTime` was improved on Linux to return time with resolution better than 1 second. nh2, what
#8144: Interface hashes include time stamp of dependent files (UsageFile mtime) -------------------------------------------------+------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time performance bug | Unknown/Multiple Test Case: | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by jstolarek): Replying to [comment:6 refold]: platform are you on? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8144#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler