Hacker News: alexgartrell

New comment by alexgartrell in "Meta’s renewed commitment to jemalloc"

alexgartrell — Tue, 17 Mar 2026 01:50:18 +0000

The linked article says they decided to do CD in 2016 fwiw so that's not inconsistent with what I said.

You reduced the number of patches a lot and also pushed very hard to get us to 3.0 after we sat on 2.6.38 ~forever. Which was very appreciated, btw. We built the whole plan going forward based on this work.

I'm not arguing that anyone should be nice to anyone or not (it's a waste of breath when it comes to Linux). I'm just saying that the benchmarking was thorough and that contemporary 2014 hardware could zero pages fast.

New comment by alexgartrell in "Meta’s renewed commitment to jemalloc"

alexgartrell — Tue, 17 Mar 2026 01:15:24 +0000

For the peanut gallery more: I worked with both of these guys at Meta on this.

The "servers are only on for a few hours" thing was like never true so I have no idea where that claim is coming from. The web performance test took more than a few hours to run alone and we had way more aggressive soaks for other workloads.

My recollection was that "write zeroes" just became a cheaper operation between '12 and '14.

A fun fact to distract from the awkwardness: a lot of the kernel work done in the early days was exceedingly scrappy. The port mapping stuff for memcached UDP before SO_REUSEPORT for example. FB binaries couldn't even run on vanilla linux a lot of the time. Over the next several years we put a TON of effort in getting as close to mainline as possible and now Meta is one of the biggest drivers of Linux development.

New comment by alexgartrell in "PythonBPF – Writing eBPF Programs in Pure Python"

alexgartrell — Mon, 15 Sep 2025 08:22:21 +0000

I did something similar a long time ago https://github.com/facebookresearch/py2bpf

It was definitely a toy, I transliterated from python bytecode (a stack based vm) into bpf. I also wrote the full code gen stack myself (bpf was simpler back then)

But using llvm and not marrying things to cpython implementation makes this approach way better

New comment by alexgartrell in "The Army’s Newest Recruits: Tech Execs From Meta, OpenAI and More"

alexgartrell — Sat, 14 Jun 2025 09:05:01 +0000

Not sure it’s relevant in the cloths these guys take

New comment by alexgartrell in "Nvidia Pushes Further into Cloud with GPU Marketplace"

alexgartrell — Sun, 25 May 2025 05:01:57 +0000

The cloud business model is to use scale and customer ownership to crush hardware margins to dust. They’re also building their own accelerators to try to cut Nvidia out altogether.

New comment by alexgartrell in "Nvidia Pushes Further into Cloud with GPU Marketplace"

alexgartrell — Sun, 25 May 2025 04:58:06 +0000

I’d imagine that these clouds are probably being incentivized to participate

New comment by alexgartrell in "The chroot Technique – a Swiss army multitool for Linux systems"

alexgartrell — Wed, 09 Apr 2025 16:09:01 +0000

I don’t think pivot_root is necessary for something like this, but a new mount namespace will definitely help avoid creating a mess on accident

New comment by alexgartrell in "VSCode’s SSH agent is bananas"

alexgartrell — Sat, 08 Feb 2025 03:09:09 +0000

New comment by alexgartrell in "Lord of the Io_uring (2020)"

alexgartrell — Mon, 06 Jan 2025 16:05:21 +0000

Sharing a queue itself is not new https://www.kernel.org/doc/html/v5.8/networking/packet_mmap.... and https://docs.kernel.org/next/userspace-api/perf_ring_buffer.... are two examples.

Issues with io_uring security mostly stemmed from an old architecture and just the fact that there's a ton of surface area.

New comment by alexgartrell in "Noisy neighbor detection with eBPF"

alexgartrell — Thu, 12 Sep 2024 05:36:12 +0000

The thing that we need in order for your dream to become a reality is excellent user space frameworks, so I encourage you (and anyone else) to go build one or (better) find one you like and contribute.

New comment by alexgartrell in "Asynchronous IO: the next billion-dollar mistake?"

alexgartrell — Sat, 07 Sep 2024 07:47:25 +0000

> File IO is perhaps the best example of this (at least on Linux). To handle such cases, languages must provide some sort of alternative strategy such as performing the work in a dedicated pool of OS threads.

AIO has existed for a long time. A lot longer than io_uring.

I think the thing that the author misses here is that the majority of IO that happens is actually interrupt driven in the first place, so async io is always going to be the more efficient approach.

The author also misses that scheduling threads efficiently from a kernel context is really hard. Async io also confers a benefit in terms of “data scheduling.” This is more relevant for workloads like memcached.

New comment by alexgartrell in "Age is a simple, modern and secure file encryption tool, format, and Go library"

alexgartrell — Mon, 05 Aug 2024 18:58:16 +0000

Yeah that’s it. Probably just wasn’t supported in the rust age library when I used it. Will double check.

New comment by alexgartrell in "Age is a simple, modern and secure file encryption tool, format, and Go library"

alexgartrell — Mon, 05 Aug 2024 14:33:19 +0000

Age is great. I used the rust crate to write an ftp server that encrypts the files before they hit disk (specific use case is having a drop box for my network scanner) and I love the simplicity and composability it provides.

One feature request: it would be awesome to have paraphrase encryption for age private keys.

New comment by alexgartrell in "Rust-Written LAVD Kernel Scheduler Shows Promising Results for Linux Gaming"

alexgartrell — Sun, 21 Apr 2024 15:12:29 +0000

The core framework (sched_ext) was written for general workloads and can quite beneficial. It lowers the costs of creating and iterating on schedulers quite a bit.

To be honest, when they started working on it I don’t think any of us expected for it to be a source of collaboration with gaming companies :)

(I’m a middle manager at Meta)

New comment by alexgartrell in "PCIe 7.0 Draft 0.5 Spec: 512 GB/s over PCIe x16 On Track For 2025"

alexgartrell — Thu, 04 Apr 2024 17:33:33 +0000

Latency and cache coherency are the other things that make this hard. Cache coherency can theoretically be resolved by CXL, so maybe we’ll get there that way.

New comment by alexgartrell in "PCIe 7.0 Draft 0.5 Spec: 512 GB/s over PCIe x16 On Track For 2025"

alexgartrell — Thu, 04 Apr 2024 17:32:20 +0000

Or perhaps more accurately, throughput is not the only goal.

New comment by alexgartrell in "Memory leak proof every C program"

alexgartrell — Sat, 20 Jan 2024 23:36:00 +0000

A professor actually told us that freeing prior to exit was harmful, because you may spend all of that time resurrecting swapped pages for no real benefit.

Counterpoint is that debugging leaks is ~hopeless unless you have the ability to prune “intentional leaks” at exit

New comment by alexgartrell in "Building end-to-end security for Messenger"

alexgartrell — Thu, 07 Dec 2023 07:27:05 +0000

As a Meta employee, I consider this a victory against NIH :)

New comment by alexgartrell in "Emmett Shear becomes interim OpenAI CEO as Altman talks break down"

alexgartrell — Mon, 20 Nov 2023 06:16:38 +0000

OpenAI's recruiting pitch was 5-10+ million/year in the form of equity. The structure of the grants is super weird by traditional big-company standards, but it was plausible enough that you could squint and call it the same. I'd posit that many of the people jumping to OpenAI are doing it for the cash and not the mission.

https://the-decoder.com/openai-lures-googles-top-ai-research....

New comment by alexgartrell in "Binance US No Longer Allows USD Withdrawal for Users"

alexgartrell — Wed, 18 Oct 2023 15:53:23 +0000

Even if the laws are stupid, the killer feature you are describing is called crime.