<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>I got it. Thanks for your tips!</div><div><br>2 окт. 2016 г., в 0:13, Jens Persson <<a href="mailto:jens@bitcycle.com">jens@bitcycle.com</a>> написал(а):<br><br></div><blockquote type="cite"><div><div dir="ltr">You could write some examples in both C and Swift in order to gain experience in how to write your Swift code so that it will (probably) run as fast as (or faster than) your corresponding C code.<div><br></div><div>I've done this for a number of different performance critical things and it is often possible to get the Swift version as fast as the C version.</div><div><br></div><div>(If you find something that is not possible (or unnecessarily cumbersome) to write as fast in Swift as in C, you could probably file a bug/improvement on <a href="http://bugs.swift.org">bugs.swift.org</a>. I did this some time ago when I noticed that Swift's optimizer missed an opportunity to unroll loops in a certain situation and it turned out that a fix/optimizer-improvement was already on its way.)</div><div><br></div><div>You must of course profile/microbenchmark your code in some meaningful way, setting all relevant compiler flags for both C and Swift, preventing dead code elimination, measuring average or perhaps median times of lots of tests, making sure what should and shouldn't be statically knowable, etc.<br></div><div><br></div><div>In Swift you probably want -O -whole-module-optimization, and (rarely) you might want/need to disable safety checks.</div><div><br></div><div>/Jens</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Oct 1, 2016 at 10:33 PM, Daniel Dunbar via swift-users <span dir="ltr"><<a href="mailto:swift-users@swift.org" target="_blank">swift-users@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Yes, it is possible. Exactly how much use of Unsafe style idioms and other performance-focused "workarounds" it requires depends a lot on the code in question. Can you say more about your problem area?<br>
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- Daniel<br>
<div class="HOEnZb"><div class="h5"><br>
> On Oct 1, 2016, at 1:30 PM, Игорь Никитин via swift-users <<a href="mailto:swift-users@swift.org">swift-users@swift.org</a>> wrote:<br>
><br>
> Hello!<br>
> Is it possible for Swift to be as fast as C when writing performance critical code? Of course if using C Standard Library for instead of Foundation (and so on) and getting rid of dynamic dispatch and reference types.<br>
> Or I need just to use C?<br>
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