Rust (programming language): Difference between revisions

Revision as of 15:30, 19 July 2025

Revision as of 15:49, 19 July 2025

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== Performance ==

Since it performs no garbage collection, Rust is often faster than other memory-safe languages.<ref>{{Cite web |last1=Anderson |first1=Tim |date=2021-11-30 |title=Can Rust save the planet? Why, and why not |url=https://www.theregister.com/2021/11/30/aws_reinvent_rust/ |access-date=2022-07-11 |website=[[The Register]] |language=en |archiveurl-datestatus=2022-07-11live |archive-url=https://web.archive.org/web/20220711001629/https://www.theregister.com/2021/11/30/aws_reinvent_rust/ |urlarchive-statusdate=live2022-07-11}}</ref><ref name="BeyondSafety"/><ref>{{Cite web |last1=Yegulalp |first1=Serdar |date=2021-10-06 |title=What is the Rust language? Safe, fast, and easy software development |url=https://www.infoworld.com/article/3218074/what-is-rust-safe-fast-and-easy-software-development.html |access-date=2022-06-25 |website=[[InfoWorld]] |language=en |archiveurl-datestatus=2022-06-24live |archive-url=https://web.archive.org/web/20220624101013/https://www.infoworld.com/article/3218074/what-is-rust-safe-fast-and-easy-software-development.html |urlarchive-statusdate=live2022-06-24}}</ref> Most of Rust's memory safety guarantees impose no runtime overhead,{{sfn|McNamara|2021|p=11}} with the exception of [[Array (data structure)|array indexing]] which is checked at runtime by default.<ref name=SaferAtAnySpeed>{{Cite journal |last1=Popescu |first1=Natalie |last2=Xu |first2=Ziyang |last3=Apostolakis |first3=Sotiris |last4=August |first4=David I. |last5=Levy |first5=Amit |date=2021-10-15 |title=Safer at any speed: automatic context-aware safety enhancement for Rust |journal=Proceedings of the ACM on Programming Languages |volume=5 |issue=OOPSLA |quote="We observe a large variance in the overheads of checked indexing: 23.6% of benchmarks do report significant performance hits from checked indexing, but 64.5% report little-to-no impact and, surprisingly, 11.8% report improved performance ... Ultimately, while unchecked indexing can improve performance, most of the time it does not." |quote-page=5 |at=Section 2 |doi=10.1145/3485480 |s2cid=238212612|doi-access=free}}</ref> Performance impact of array indexing bounds checks varies, but can be significant in some cases.<ref name=SaferAtAnySpeed/>

Rust provides two "modes": safe and unsafe. Safe mode is the "normal" one, in which most Rust is written. In unsafe mode, the developer is responsible for the code's memory safety, which is used by developers for cases where the compiler is too restrictive.<ref name="UnsafeRustUse">{{Cite journal |last1=Astrauskas |first1=Vytautas |last2=Matheja |first2=Christoph |last3=Poli |first3=Federico |last4=Müller |first4=Peter |last5=Summers |first5=Alexander J. |date=2020-11-13 |title=How do programmers use unsafe rust? |url=https://dl.acm.org/doi/10.1145/3428204 |journal=Proceedings of the ACM on Programming Languages |language=en |volume=4 |issue=OOPSLA |pages=1–27 |doi=10.1145/3428204 |issn=2475-1421|hdl=20.500.11850/465785 |hdl-access=free}}</ref>

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Many of Rust's features are so-called ''zero-cost abstractions'', meaning they are optimized away at compile time and incur no runtime penalty.{{sfn|McNamara|2021|p=19, 27}} The ownership and borrowing system permits [[zero-copy]] implementations for some performance-sensitive tasks, such as [[parsing]].<ref>{{Cite book |last=Couprie |first=Geoffroy |title=2015 IEEE Security and Privacy Workshops |chapter=Nom, A Byte oriented, streaming, Zero copy, Parser Combinators Library in Rust |date=2015 |pages=142–148 |doi=10.1109/SPW.2015.31 |isbn=978-1-4799-9933-0 |s2cid=16608844 }}</ref> [[Static dispatch]] is used by default to eliminate [[method call]]s, except for methods called on dynamic trait objects.{{sfn|McNamara|2021|p=20}} The compiler also uses [[inline expansion]] to eliminate [[function call]]s and statically-dispatched method invocations.<ref>{{Cite web |title=Code generation |url=https://doc.rust-lang.org/reference/attributes/codegen.html |access-date=2022-10-09 |website=The Rust Reference |archive-date=2022-10-09 |archive-url=https://web.archive.org/web/20221009202615/https://doc.rust-lang.org/reference/attributes/codegen.html |url-status=live}}</ref>

Since Rust uses [[LLVM]], all performance improvements in LLVM apply to Rust also.<ref name="how-fast-is-rust">{{cite web |url=https://doc.rust-lang.org/1.0.0/complement-lang-faq.html#how-fast-is-rust? |title=How Fast Is Rust? |website=The Rust Programming Language FAQ |access-date=11 April 2019 |archive-date=28 October 2020 |archive-url=https://web.archive.org/web/20201028102013/https://doc.rust-lang.org/1.0.0/complement-lang-faq.html#how-fast-is-rust? |url-status=live}}</ref> Unlike C and C++, Rust allows for reordering struct and enum elements<ref>{{Cite book |last1=Farshin |first1=Alireza |last2=Barbette |first2=Tom |last3=Roozbeh |first3=Amir |last4=Maguire |first4=Gerald Q. Jr |last5=Kostić |first5=Dejan |year=2021 |url=https://dlnext.acm.org/doi/abs/10.1145/3445814.3446724 |access-date=2022-07-12 |language=en |doi=10.1145/3445814.3446724 |quote=... While some compilers (e.g., Rust) support structure reordering [82], C & C++ compilers are forbidden to reorder data structures (e.g., struct or class) [74] ... |title=Proceedings of the 26th ACM International Conference on Architectural Support for Programming Languages and Operating Systems |chapter=PacketMill: Toward per-Core 100-GBPS networking |pages=1–17 |isbn=9781450383172 |s2cid=231949599 |archiveurl-datestatus=2022-07-12live |archive-url=https://web.archive.org/web/20220712060927/https://dlnext.acm.org/doi/abs/10.1145/3445814.3446724 |urlarchive-statusdate=live2022-07-12 |quote=... While some compilers (e.g., Rust) support structure reordering [82], C & C++ compilers are forbidden to reorder data structures (e.g., struct or class) [74] ... }}</ref> to reduce the sizes of structures in memory, for better memory alignment and efficiency.{{sfn|Gjengset|2021|p=22}}

== Adoption ==