Samat

[Brett Harrison @BrettHarrison]

In 2015 I formed a small group of engineers at Jane Street to rebuild the firm’s core trading system from the ground up, and we ended up cutting latency by two orders of magnitude. Some of the techniques we used, relevant for algorithmic trading systems and exchanges today:

Zero allocation: Whenever a program allocates memory for an object on the heap, the runtime pays a steep penalty in latency. The simplest solution is to avoid memory allocation entirely.

Jane Street famously uses OCaml, a strongly typed programming language that by default produces garbage collected by a dynamic collector. Most other firms use languages with manual memory management, but it was a strict part of Jane Street’s tech culture that all risk-sensitive code had to be written in OCaml. It took a collaborative effort across multiple groups within Jane Street’s technology org to create zero-allocation core libraries, combining the type safety of a functional programming language with the memory profile of a language like C.

We built the new main trading loop in this hybrid OCaml/C-style, producing zero new allocations in the critical path from tick to trade. In modern languages like Rust, it is substantially easier to achieve precise memory management while still benefiting from type safety and compile-time guarantees.

Kernel bypass: A primary goal of a low-latency trading system or exchange is to pull a network packet containing market data or order flow through the network card’s interface and into the program’s memory space as fast as possible. The standard Linux OS kernel uses slow abstractions to support a wide variety of network drivers, at the expense of the entire system’s end-to-end latency. When we started with an empty program that contained no business logic and only forwarded packets through when received, the end-to-end latency was already too slow.

To fix this issue, we employed a standard practice in the HFT industry in which we bypassed the OS’s kernel stack entirely by leveraging our network card vendors’ proprietary APIs to DMA packets straight from the NIC into memory. This technique brought our empty-packet-forwarding baseline into the latency regime we needed in order to build out the rest of the trading, risk, and protocol code.

Local IPC: Kernel bypass is necessary when reading routed packets off a network from a third party such as another exchange or client connection. When communicating between internal instead of external processes, the fastest transports avoid network stacks entirely.

Processes within the same box can transfer messages using shared memory or Unix domain sockets. This allowed us to continue with our familiar process boundaries for separable components without sacrificing significant performance. We had to write custom logic to emulate many of the features of network- and transport-layer protocols, with the result of creating a reusable, zero-overhead IPC mechanism.

Working on this problem was one of the most intellectually rewarding experiences of my early career. The above latency optimization techniques are fairly commonplace in the HFT trade but hard to learn outside the industry setting. Half of our team at Architect comes from Jane Street and other trading firms, and we value using our domain knowledge to build exchanges for the public rather than trading software that never leaves an HFT’s walls.

[Askar S. @askarsyzdykov]

С помощью ловкости рук и щепотки магии получилось пройти проверку Apple.
Теперь можно перейти из https://t.co/WqShFyyLk7 в приложения провайдеров. Пока все еще костыльно, но лучше, чем просто карта с маркерами.

https://t.co/jkM9WRVsBE

[kenneth @kennethnym]

sneak peek of new website design

[Dr. Jennifer Cassidy @OxfordDiplomat]

Three months ago there were 36 hospitals in Gaza. This morning there are none. Zero. All have been bombed by Israel. The same country that claimed at the International Court of Justice that they would never attack a hospital.

[Samat @samlabs821]

@askarsyzdykov политика гугла скорее всего

[Samat @samlabs821]

@askarsyzdykov https://t.co/0RONfEv7ho

[Samat @samlabs821]

Пора забанить слово openai в ленте)

[Samat @samlabs821]

top!

[Mitchell Hashimoto @mitchellh]

Have you ever wanted your terminal to look like an authentic CRT? Of course you have. Well, LOOK NO FURTHER because the future (or is it the past?) is now. And people ask why you'd ever need a GPU-rendered terminal.... HAH! My yak has no more hair to shave.

This demo is crazier than it seems: you can actually specify any custom shader, and the shader API is compatible with ShaderToy, so you can take any off-the-shelf shader from ShaderToy and this works.

The tech behind this is super over the top. Ghostty is cross-platform and uses Metal directly on macOS and OpenGL on Linux. Metal and OpenGL use different shading languages. No problem! You specify the custom shader in GLSL (OpenGL language) and it’s automatically translated to SPIR-V (binary IR) then automatically translated to MSL (Metal language). That all happens at runtime because why not.

Yeah but this has to kill your battery right? Nope! <1% CPU and <1% GPU because computers are fast (especially when you're working at a relatively low level).

[Samat @samlabs821]

@deedarb https://t.co/bClIwJg3Mg

[Samat @samlabs821]

started using nix profile install nixpkgs#pkgName instead of brew install

[Samat @samlabs821]

@deedarb У Никс Есть роллбэк. Ты можешь запиннить версию и переключатся между ними

[Samat @samlabs821]

I just scored 51 WPM and 90% ACC typing "Alice in Wonderland: Chapter 1" at https://t.co/gYgLsdV5bN #typing #books

[Samat @samlabs821]

'cargo install bat exa'
'bat filename'
'exa --la --git'

[Samat @samlabs821]

@Kepler13A Или хотел проверить, мало ли, вдруг не откроется

[Benjamin Partridge @benpartridge]

Succession characters as my car (thread)

Login Roy - been around the block and seen it all, making a rattling noise, basically dead, it's my 2009 Hyundai i10.

[Samat @samlabs821]

@nurgali_e Так в этом же и весь смысл, так как нет мака ;)

[Samat @samlabs821]

уже больше 2х недель перешел на PopOS. Вначале не смог привыкнуть к tiling window - просто отключил его. со временем начал использовать. Очень удобно если это ноутбук с экраном fullhd.

[Samat @samlabs821]

перемещение и переключение через super+shift, super+ctrl/ можно через alt-tab

[Samat @samlabs821]

It's my #Twitterversary! I have been on Twitter for 12 years, since 29 Sep 2010 (via @twi_age).

[Samat @samlabs821]

все поняли да?!