the8472 (u/the8472) - Readit News

the8472 commented on In-Memory Filesystems in Rust andre.arko.net/2025/08/18... · Posted by u/ingve

the8472 · 8 hours ago

> but all my benchmarks seem to disagree.

Well, benchmarks could be wrong or misleading. Did you make sure that the IO actually happens and that it dominates the process execution time?

the8472 commented on In-Memory Filesystems in Rust andre.arko.net/2025/08/18... · Posted by u/ingve

maxbond · 11 hours ago

ETA: See correction below.

To be clear `File::drop()` does sync, it just ignores errors (because `drop()` doesn't have a way of returning an error). It's not really Rust specific I guess, I just don't know off the top of my head what other languages behave this way.

the8472 · 8 hours ago

> To be clear `File::drop()` does sync

It does not. BufWriter<File> flushes its userspace buffer (but doesn't fsync either). If you have a bare File then drop really just closes the file descriptor, that's it.

https://github.com/rust-lang/rust/blob/ee361e8fca1c30e13e7a3...

the8472 commented on In-Memory Filesystems in Rust andre.arko.net/2025/08/18... · Posted by u/ingve

maxbond · 11 hours ago

A Rust-specific danger is that, if you don't explicitly sync a file before dropping it, any errors from syncing are ignored. So if you care about atomicity, call eg `File::sync_all()`.

the8472 · 8 hours ago

On most filesystems close(2) is nearly a noop, so even if you surfaced errors from close it returning successfully would not guarantee an absence of errors.

close without fsync (or direct IO) essentially is telling the OS that you don't need immediate durability and prefer performance instead.

the8472 commented on The oldest unopened bottle of wine in the world openculture.com/2025/08/t... · Posted by u/bookofjoe

throwup238 · a day ago

> Why, and more importantly how would it lose its ethanol content?

Most wine bottles lose their ethanol within decades because oxygen makes it through the seal and the ethanol evaporates or reacts into something else. Any wine bottle that survives to hundreds of years old, even perfectly sealed, will have bacteria converting ethanol to acetaldehyde and acetic acid via aerobic and anaerobic pathways. 200-300 years is normally the limit before wine loses all ethanol even without a leak.

the8472 · 21 hours ago

Perhaps with a dash of cobalt-60 we can ensure both a long shelf-life and discourage premature opening.

the8472 commented on The first Media over QUIC CDN: Cloudflare moq.dev/blog/first-cdn/... · Posted by u/kixelated

parhamn · 3 days ago

That "just announced" link is really good if you have no idea what this is about: https://blog.cloudflare.com/moq/ (I missed it)

the8472 · 2 days ago

> Sub-second latency at broadcast scale

Alas, no actual multicast.

the8472 commented on Mark Zuckerberg freezes AI hiring amid bubble fears telegraph.co.uk/business/... · Posted by u/pera

Q6T46nT668w6i3m · 4 days ago

There’s no evidence that it’ll scale like that. Progress in AI has always been a step function.

the8472 · 4 days ago

rodent -> homo sapiens brain scales just fine? It's tenuous evidence, but not zero.

the8472 commented on AWS in 2025: Stuff you think you know that's now wrong lastweekinaws.com/blog/aw... · Posted by u/keithly

the8472 · 5 days ago

> As of very recently, you can also force EC2 instances to stop or terminate without waiting for a clean shutdown or a ridiculous timeout

Not true for GPU instances, they're stuck 5 minutes in a stopping state because they run some GPU health checks.

the8472 commented on Without the futex, it's futile h4x0r.org/futex/... · Posted by u/eatonphil

nromiun · 6 days ago

Is it just me or moving things out of kernel space improves performance in general? Like context switching, mutex or entire TCP stack. I wonder what else can be moved into user space.

the8472 · 6 days ago

io_uring alleviates a lot of those problems by essentially providing a batched, asynchronous syscall API, including futex calls, as mentioned in other comments.

the8472 commented on Without the futex, it's futile h4x0r.org/futex/... · Posted by u/eatonphil

jauntywundrkind · 6 days ago

Windows gained a WaitForMultipleObjects, which Linux 5.16 (end 2021) aped with a new Futex2. https://www.phoronix.com/news/Linux-5.16-sys_futex_waitv

There's been a nice stream of improvements to futex2 since.

NUMA support (finally landing!), https://www.phoronix.com/news/FUTEX2-NUMA-Small-Futex https://www.phoronix.com/news/FUTEX2-Improvements-Linux-6.16 (see also this fantastic recent submission on NUMA in general, absolutely critical performance stuff, https://news.ycombinator.com/item?id=44936575)

Io_uring support in 6.7 (2024), (with a nice write up on it speeding up postgresql aio), https://www.phoronix.com/news/IO_uring-FUTEX-Linux-6.7

Small requeue and single wait additions in 6.7, https://www.phoronix.com/news/Linux-6.7-Locking-FUTEX2

the8472 · 6 days ago

But still no futex_swap[0][1]

[0] https://lore.kernel.org/all/414e292195d720c780fab2781c749df3... [1] https://blog.linuxplumbersconf.org/2013/ocw/system/presentat...

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KarmaCake day12533June 4, 2013View Original