#15938: Hadrian's recompilation check is extremely slow -------------------------------------+------------------------------------- Reporter: bgamari | Owner: alpmestan Type: bug | Status: patch Priority: high | Milestone: 8.8.1 Component: Build System | Version: 8.6.2 (Hadrian) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5412 Wiki Page: | -------------------------------------+------------------------------------- Changes (by alpmestan): * status: new => patch * differential: => Phab:D5412 Comment: Got a patch up at https://phabricator.haskell.org/D5412. This cuts the pauses quite significantly, as expected. From 45-60s down to <5s, when resuming the build from a similar point. With Neil's shake changes mentionned above (which I have not tried yet), I'm confident we won't be seeing those pauses again before quite some time. The next bottleneck seems to be our program lookup in `Rules.Program.buildProgram`. We're also still doing a similarly "big" (not as big as the `compilePackage` one that my patch fixes) listing of contexts and generation of rules in `Rules.hs`, see `vanillaContexts`. Finally, my patch does require to lookup the `Package` from its `pkgPath` that we parse from the file path, but at least it's not at rule generation time. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15938#comment:35 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler