librope
WebKit
librope | WebKit | |
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4 | 152 | |
265 | 7,498 | |
- | 2.3% | |
0.0 | 10.0 | |
over 2 years ago | 2 days ago | |
C | ||
GNU General Public License v3.0 or later | - |
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librope
- Show HN
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The case against an alternative to C
Yep. A few years ago I implemented a skip list based rope library in C[1], and after learning rust I eventually ported it over[2].
The rust implementation was much less code than the C version. It generated a bigger assembly but it ran 20% faster or so. (I don't know why it ran faster than the C version - this was before the noalias analysis was turned on in the compiler).
Its now about 3x faster than C, thanks to some use of clever layered data structures. I could implement those optimizations in C, but I find rust easier to work with.
C has advantages, but performance is a bad reason to choose C over rust. In my experience, the runtime bounds checks it adds are remarkably cheap from a performance perspective. And its more than offset by the extra optimizations the rust compiler can do thanks to the extra knowledge the compiler has about your program. If my experience is anything to go by, naively porting C programs to rust would result in faster code a lot of the time.
And I find it easier to optimize rust code compared to C code, thanks to generics and the (excellent) crates ecosystem. If I was optimizing for runtime speed, I'd pick rust over C every time.
[1] https://github.com/josephg/librope
[2] https://github.com/josephg/jumprope-rs
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Why Is C Faster Than Java (2009)
> it’s not clear if this will be a positive for native dev advocacy
I've rewritten a few things in rust. Seems pretty positive to me, because you can mix some of the best optimizations and data structures you'd write in C, with much better developer ergonomics.
A few years ago I wrote a rope library in C. This is a library for making very fast, arbitrary insert & delete operations in a large string. My C code was about as fast as I could make it at the time. But recently, I took a stab at porting it to Rust to see if I could improve things. Long story short, the rust version is another ~3x faster than the C version.
https://crates.io/crates/jumprope
(Vs in C: https://github.com/josephg/librope )
The competition absolutely isn't fair. In rust, I managed to add another optimization that doesn't exist in the C code. I could add it in C, but it would have been really awkward to weave in. Possible, but awkward in an already very complex bit of C. In rust it was much easier because of the language's ergonomics. In C I'm using lots of complex memory management and I don't want to add complexity in case I add memory corruption bugs. In rust, well, the optimization was entirely safe code.
And as for other languages - I challenge anyone to even approach this level of performance in a non-native language. I'm processing ~30M edit operations per second.
But these sort of performance results probably won't scale for a broader group of programmers. I've seen rust code run slower than equivalent javascript code because the programmers, used to having a GC, just Box<>'ed everything. And all the heap allocations killed performance. If you naively port python line-by-line to rust, you can't expect to magically get 100x the performance.
Its like, if you give a top of the line Porsche to an expert driver, they can absolutely drive faster. But I'm not an expert driver, so I'll probably crash the darn thing. I'd take a simple toyota or something any day. I feel like rust is the porsche, and python is the toyota.
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Rust is now overall faster than C in benchmarks
> I have no idea whether that matters or even easy to measure...
It is reasonably easy to measure, and the GP is about right. I've measured a crossover point of around a few hundred items too. (Though I'm sure it'll vary depending on use case and whatnot.)
I made a rope data structure a few years ago in C. Its a fancy string data structure which supports inserts and deletes of characters at arbitrary offsets. (Designed for text editors). The implementation uses a skip list (which performs similarly to a b-tree). At every node we store an array of characters. To insert or delete, we traverse the structure to find the node at the requested offset, then (usually) memmove a bunch of characters at that node.
Q: How large should that per-node array be? A small number would put more burden on the skip list structure and the allocator, and incur more cache misses. A large number will be linearly slower because of all the time spent in memmove.
Benchmarking shows the ideal number is in the ballpark of 100-200, depending on CPU and some specifics of the benchmark itself. Cache misses are extremely expensive. Storing only a single character at each node (like the SGI C++ rope structure does) makes it run several times slower. (!!)
Code: https://github.com/josephg/librope
This is the constant to change if you want to experiment yourself:
https://github.com/josephg/librope/blob/81e1938e45561b0856d4...
In my opinion, hash tables, btrees and the like in the standard library should probably swap to flat lists internally when the number of items in the collection is small. I'm surprised more libraries don't do that.
WebKit
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GPU Compute in the Browser at the Speed of Native: WebGPU Marching Cubes
Multiple engineers are working on adding it back: https://github.com/WebKit/WebKit/pulls?q=is%3Apr+is%3Aclosed...
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HTML Streaming and DOM Diffing Algorithm
Since 2023 Chrome announced the View Transition API, and it looks like Safari is also going to support it soon.
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Towards memory safety with ownership checks for C
One heap per type.
Here’s an allocator optimized for that use case.
https://github.com/WebKit/WebKit/blob/main/Source/bmalloc/li...
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Bun, JavaScript, and TCO
To use this in Bun, you’d have to start Bun with the environment variable “BUN_JSC_useDollarVM=1” and then $vm.createBuiltin(mySourceCodeString)
When using this intrinsic, if any of the arguments are incorrect or it cannot otherwise enable it, the entire process will probably crash. In debug builds of JSC it will have a nicer assertion failure but that is not enabled in release builds
Example code: https://github.com/WebKit/WebKit/blob/17351231b4dedb62d81721...
also happy to answer any questions about Bun
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Show HN: Rem: Remember Everything (open source)
Ah, good, let me introduce you to the wonderful world of the Chrome Devtools Protocol! (fka Chrome Remote Debugging Protocol)
I love this API for almost everything browser related. I built my RBI product atop this (BrowserBox: https://dosyago.com), and I think it's a drastically underrated API.
Also, it works out of the box in Edge, Brave, Chromium, and many parts of CRDP are supported by Firefox and Safari^1
1: See for example: https://github.com/WebKit/webkit/tree/main/Source/JavaScript...
- WebGPU now available for testing in Safari Technology Preview
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Disabling iOS Personalized Ads tells kernel to kill daemon every 3 seconds
No, it's unrelated.
https://github.com/WebKit/WebKit/commit/064df1a9f395f8c6e32c...
- Apple's Safari browser is still vulnerable to Spectre attacks
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Replacing WebRTC: real-time latency with WebTransport and WebCodecs
It's being worked on now: https://github.com/WebKit/WebKit/pull/17320
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iLeakage: Browser-Based Timerless Speculative Execution Attacks on Apple Devices
It is different. The cross-site navigation flag is a couple of years old. It was enabled by default for iOS in November 2018 for example https://github.com/WebKit/WebKit/commit/e191fc8c412850cb9fd0...
What are some alternatives?
c2rust - Migrate C code to Rust
chromium - The official GitHub mirror of the Chromium source
mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.
otter-browser - Otter Browser aims to recreate the best aspects of the classic Opera (12.x) UI using Qt5
c3c - Compiler for the C3 language
cname-trackers - This repository contains a list of popular CNAME trackers
proposal-explicit-resource-management - ECMAScript Explicit Resource Management
fingerprintjs - Browser fingerprinting library. Accuracy of this version is 40-60%, accuracy of the commercial Fingerprint Identification is 99.5%. V4 of this library is BSL licensed.
jumprope-rs
gecko-dev - Read-only Git mirror of the Mercurial gecko repositories at https://hg.mozilla.org. How to contribute: https://firefox-source-docs.mozilla.org/contributing/contribution_quickref.html
buffet - All-inclusive Buffer for C
uBlock-Safari - uBlock Origin - An efficient blocker for Chromium, Firefox, and Safari. Fast and lean.