Thanks for that link, used it to track down the worst compile time offender:
This piece of code:
public func logAddrInfoIPAddresses(_ infoPtr: UnsafeMutablePointer<addrinfo>)
-> String {
let addrInfoNil: UnsafeMutablePointer<addrinfo>? = nil
var count: Int = 0
var info: UnsafeMutablePointer<addrinfo> = infoPtr
var str: String = ""
while info != addrInfoNil {
let (clientIp, service) = sockaddrDescription(info.pointee.ai_addr)
str += "No: \(count), HostIp: " + (clientIp ?? "?") + " at port: " +
(service ?? "?") + "\n"
count += 1
info = info.pointee.ai_next
}
return str
}
Took 38 seconds to compile.
Removing the “str” assignment:
public func logAddrInfoIPAddresses(_ infoPtr: UnsafeMutablePointer<addrinfo>)
-> String {
let addrInfoNil: UnsafeMutablePointer<addrinfo>? = nil
var count: Int = 0
var info: UnsafeMutablePointer<addrinfo> = infoPtr
var str: String = ""
while info != addrInfoNil {
let (clientIp, service) = sockaddrDescription(info.pointee.ai_addr)
// str += "No: \(count), HostIp: " + (clientIp ?? "?") + " at port: " +
(service ?? "?") + "\n"
count += 1
info = info.pointee.ai_next
}
return str
}
Brought it down to 6.6ms
Obviously I have to rewrite, but it does show how just one line of code can be
responsible for approx 80% of the compile time.
Regards,
Rien
Site: http://balancingrock.nl
Blog: http://swiftrien.blogspot.com
Github: http://github.com/Balancingrock
Project: http://swiftfire.nl
> On 22 Mar 2017, at 23:41, Greg Parker via swift-users <swift-users@swift.org>
> wrote:
>
>>
>> On Mar 22, 2017, at 1:03 PM, piotr gorzelany via swift-users
>> <swift-users@swift.org> wrote:
>>
>> Hi, I hope I reached the right mailing list to ask a question about tooling.
>>
>> Can somebody from the compiler or Xcode team share some tips on how to
>> improve compilation times of larger Swift projects?
>>
>> I am an iOS developer and the largest issue my team has with Swift so far is
>> that when the project gets semi large (~30 000 lines) the compilation times
>> start to be high (~10 minutes from clean). This is a MAJOR downside since
>> iOS development oftentimes requires rapid changes to UI or logic. Every
>> person of my team compiles a project at least 10 times a day to test new
>> features or functionalities. When compilation times start to be higher than
>> 10 minutes that gets us to ~1.5h a day of developer time spend just on
>> compiling. Not to mention the focus lost when this is happening.
>>
>> I know the Swift Evolution list is buzzing with new ideas and features but
>> from my experience the compilation times is a CRITICAL thing to improve in
>> the next Swift release since it cost real money to waste all those developer
>> hours. Just think of all the hours lost on compiling across all Swift devs
>> worldwide and you will get to probably dozens of thousand of dev hours a day.
>>
>> Is the core compiler team going to address compilation performance in the
>> next release?
>>
>> Maybe there is an existing solution to long compilation times that we don't
>> know of? It would be great if anybody could share.
>> I was thinking maybe of dividing the app into multiple frameworks since I
>> think frameworks are compiled only once only on change?
>
> Build time is always a goal. Pretty much every version of Swift has had
> changes intended to improve compilation time or decrease the frequency of
> recompilation.
>
> Often a large part of the build time is spent in a handful of places where
> the compiler's type inference system behaves poorly. You can use the
> -debug-time-function-bodies and -debug-time-expression-type-checking flags to
> look for these places. You can often get huge decreases in compile time by
> adding an explicit type declaration in the right place in order to simplify
> the type inference engine's job.
>
> Here's a walkthough of one such analysis:
> Profiling your Swift compilation times
> http://irace.me/swift-profiling
>
>
> --
> Greg Parker gpar...@apple.com Runtime Wrangler
>
>
> _______________________________________________
> swift-users mailing list
> swift-users@swift.org
> https://lists.swift.org/mailman/listinfo/swift-users
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