I just tried with both Xcode 8.1 beta 2 and Xcode 8.0, and 8.1b2 seems maybe 15s faster (to build our main huge target): 7m28s compared to 7m43s. It's some improvement, but I'm not exactly sure what kind of improvement was expected.
Is there any profiling/tracing you all would recommend to help find problem areas? I don't mind building from Swift master, using someone's preferred profiling tools, etc. I'm not really sure where to start. Ben On Wed, Oct 5, 2016 at 1:05 PM, Ben Asher <benashe...@gmail.com> wrote: > Apologies for not starting off with system info: macOS Sierra (10.12.0), > Xcode 8.0 (from the App Store). > > I'll try with Xcode 8.1 beta this afternoon and report back. Ill also open > a ticket for improving -debug-time-function-bodies if I can confirm > anything. > > Thanks! > > Ben > > On Wed, Oct 5, 2016 at 1:00 PM, Mark Lacey <mark.la...@apple.com> wrote: > >> >> On Oct 4, 2016, at 2:38 PM, Ben Asher via swift-dev <swift-dev@swift.org> >> wrote: >> >> Hello! I work with a large project (~900 .swift files and more .m files). >> We have a nightly job that compiles the app and calls out function bodies >> (using -debug-time-function-bodies) that are slower than 100ms to >> compile. Since upgrading to Swift 3, the number of trouble function bodies >> has one from > 150 to < 20, so we're really happy about that! The only >> issue though is that build time overall increased by ~1 min (amount of time >> to build all targets before automatically merging to master in our >> integration build). >> >> >> Is this using a particular release of Xcode (8.0 or an 8.1 beta?), or >> with one of the toolchain builds from swift.org? >> >> Xcode 8.1 beta 2 includes some type checker performance improvements >> which might have an impact here. >> >> >> To dig into this further, we've started a new nightly job that builds the >> app using the -debug-time-compilation flag, and using that we've found that >> some files take as long as 2-3 seconds to compile. But, there's no targeted >> output to help us get this down via the -debug-time-function-bodies flag >> (i.e. no function bodies that we can refactor to get compile times much >> faster). >> >> >> One thing to look out for here is that I believe there are some cases >> where -debug-time-function-bodies isn’t reporting type checking time. From >> my (potentially faulty) recollection, things like let bindings with >> literals or closures on the right hand side do not show up in the >> -debug-time-function-bodies output, and depending on the specifics of the >> expression these can sometimes take a long time to type check. When these >> appear within the body of another type declaration they can end up getting >> type checked multiple times during a full project build, and that time can >> add up. >> >> I don’t believe there is a bug open for improving >> -debug-time-function-bodies to help diagnose this, but opening a bug would >> be appreciated if you can confirm that this is the case, and of course >> patches to fix it are definitely welcome as well. >> >> Mark >> >> We can see that most of the time is spent in "Type checking / Semantic >> analysis" for these problem files, but we don't currently have any way of >> knowing what that means. It feels like we've exhausted the available >> options at this point (unless there are other flags I'm missing) in terms >> of existing actionable debugging/profiling/reporting, so now our question >> is this: what kind of reports would Swift maintainers be interested in >> seeing in terms of output from profiling tools, etc. to help debug/diagnose >> these slow compile issues? We're willing to devote time to tooling to help >> generate such reports and file bugs. >> >> Thanks! >> >> Ben >> _______________________________________________ >> swift-dev mailing list >> swift-dev@swift.org >> https://lists.swift.org/mailman/listinfo/swift-dev >> >> >> > > > -- > -Ben > -- -Ben
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