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Zlib-rs is faster than C

(trifectatech.org)
341 points dochtman | 2 comments | 16 Mar 25 19:35 UTC | HN request time: 0.399s | source
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YZF ◴[16 Mar 25 20:12 UTC] No.43381858[source]▶
I found out I already know Rust:

        unsafe {
            let x_tmp0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x10);
            xmm_crc0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x01);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, x_tmp0);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, xmm_crc0);
Kidding aside, I thought the purpose of Rust was for safety but the keyword unsafe is sprinkled liberally throughout this library. At what point does it really stop mattering if this is C or Rust?

Presumably with inline assembly both languages can emit what is effectively the same machine code. Is the Rust compiler a better optimizing compiler than C compilers?

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1. fxtentacle ◴[17 Mar 25 08:52 UTC] No.43386389[source]▶
Yeah, this article about a rust "win" perfectly illustrates why I distrust all good news about it.

Rust zlib is faster than zlib-ng, but the latter isn't a particularly fast C contender. Chrome ships a faster C zlib library which Rust could not beat.

Rust beat C by using pre-optimized code paths and then C function pointers inside unsafe. Plus C SIMD inside unsafe.

I'd summarize the article as: generous chunks of C embedded into unsafe blocks help Rust to be almost as fast as Chrome's C Zlib.

Yay! Rust sure showed it's superiority here!!!!1!1111

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2. FreshOldMage ◴[17 Mar 25 10:28 UTC] No.43386894[source]▶
Did you even read the article? They compare specifically against the Chrome zlib library and beat it at 10 out of 13 chunk sizes considered.