#9221: (super!) linear slowdown of parallel builds on 40 core machine -------------------------------------+------------------------------------- Reporter: carter | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #910, #8224 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rrnewton): If blackholing *is* the culprit then I wonder how localized the strictification will need to be... Ezyang's multi-process suggestion seems appealing. But if it's a `forkProcess` approach, is it possible to load most of the relevant state into memory before forking a child process per module? That could avoid or reduce communication through files or shared pages. The granularity of per-module compiles is big, so maybe processes would be ok. Also, there's the nice side effect that the GCs of child processes are disentangled, removing that particular scaling bottleneck. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9221#comment:42 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler