#13944: Introduce synchronized FFI -------------------------------------+------------------------------------- Reporter: winter | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by winter): I have did some benchmarks[https://github.com/winterland1989/stdio/tree/newFD/bench/diskIO here], my conclusion is that under concurent disk I/O situations, safe FFI can cause a slow down up to 50%. The problem is if the disk is slow enough, or the file is not in page cache, then safe FFI may be a good choice. OTOH, if a blocking read doesn't take too much time, we'd better simply issue an unsafe read. I can't answer all the questions you're asking now though, i'm thinking for disk I/O a small thread pool maybe a better answer, since the I/O throughput will not increase or even downgrade when conncurrent number exceed a certain value. (for example, libuv do this). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13944#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler