Hacker News: deivid

New comment by deivid in "Show HN: Sub-millisecond VM sandboxes using CoW memory forking"

deivid — Wed, 18 Mar 2026 08:34:16 +0000

Niiiiiice, I've been working on something like this, but reducing linux boot time instead of snapshot restore time; obviously my solution doesn't work for heavy runtimes

New comment by deivid in "Linux Page Faults, MMAP, and userfaultfd for fast sandbox boot times"

deivid — Thu, 12 Mar 2026 21:19:17 +0000

Says fast, but how fast? Didn't really see any measurements

New comment by deivid in "Tiny C Compiler"

deivid — Sat, 07 Feb 2026 22:49:58 +0000

TCC is fantastic! Very hackable, easy to compile to WASM for some interesting in-browser compilation

New comment by deivid in "Gathering Linux Syscall Numbers in a C Table"

deivid — Thu, 22 Jan 2026 17:37:39 +0000

That makes sense, I guess this was not a problem for the times I needed nolibc.

I do agree that trying to extract data/logic from linux is a pain -- I've tried a few times to extract some of the eBPF verifier handling, but end up pulling most of the kernel along.

New comment by deivid in "Hands-On Introduction to Unikernels"

deivid — Thu, 22 Jan 2026 17:34:43 +0000

Unikraft is cool, I still have it in my 'todo' list to play around with sometime.

Linking the app with the 'kernel' seems pretty nice, would be cool to see what that looks like for a virtio-only environment.

Just wanted to point out that the 150ms is not snapshot based, you can get <10ms for small vms (128MB ram, 2GB ram moves you to ~15ms range), for 'cold' boots.

New comment by deivid in "Gathering Linux Syscall Numbers in a C Table"

deivid — Thu, 22 Jan 2026 13:47:50 +0000

Would it be cheating to use the kernel's nolibc?

New comment by deivid in "Hands-On Introduction to Unikernels"

deivid — Thu, 22 Jan 2026 13:28:33 +0000

You can do <10ms. I was working to see if I could get it under 1ms, but my best was 3.5ms

New comment by deivid in "Hands-On Introduction to Unikernels"

deivid — Thu, 22 Jan 2026 13:27:47 +0000

You can boot a vm without snapshots in < 10ms, just need a minimal kernel.

New comment by deivid in "Hands-On Introduction to Unikernels"

deivid — Thu, 22 Jan 2026 07:42:21 +0000

This is really well written, thanks for sharing.

I didn't understand the point of using Unikraft though, if you can boot linux in much less than 150ms, with a far less exotic environment

New comment by deivid in "Interactive eBPF"

deivid — Fri, 16 Jan 2026 12:54:35 +0000

I wanted to add all kind of exercises, but I'm not sure what's a good way of presenting a deployment exercise.

On libbcc specifically, I'm not sure it's worth it, CO-RE / BTF is where things are heading, and any reasonably new kernel supports it (<5 years old)

New comment by deivid in "Interactive eBPF"

deivid — Fri, 16 Jan 2026 10:56:16 +0000

Thanks for sharing my site!

I've been thinking about building a platform like this for a while, and it was quite fun to build.

Let me know if you have questions or ideas for new exercises.

New comment by deivid in "OLED, Not for Me"

deivid — Sat, 10 Jan 2026 08:38:06 +0000

Downsizing from a 27" 5k to a 24" 4k, could not find anything besides a new company called JAPANNEXT (they are French)

New comment by deivid in "Static Allocation for Compilers"

deivid — Mon, 29 Dec 2025 23:30:11 +0000

It's an interesting idea. I'm butchering TCC (tiny c compiler) for a side project/experiment, and using arenas sped it up 2x. This of course requires the memory limit to be specified in advance, but for my situation that's fine.

New comment by deivid in "Rex is a safe kernel extension framework that allows Rust in the place of eBPF"

deivid — Sun, 28 Dec 2025 14:49:45 +0000

IMO eBPF is best viewed as a mechanism that allows you to load "arbitrary" code in specific kernel paths, while guaranteeing that the kernel won't hang or crash.

That's it. Though I said "arbitrary" because the program has to pass the verifier, which limits valid programs to ones where it can make the stability guarantees.

New comment by deivid in "Ask HN: What Are You Working On? (December 2025)"

deivid — Mon, 15 Dec 2025 07:55:16 +0000

I'm not sure it'll be a serious project, but the main goal is to use it in CI or dev, where setting up postgres is kind of a pain.

I got it to work already by setting up the global context in single-user mode (like postgres --single) and exposing bindings for SPI operations.

Yesterday night I got extensions working, but as this project builds as a static archive, the extensions also have to be part of the build. Both plpgsql and pgvector worked fine.

The bigger challenge is dealing with global state -- comparing the pre-start and post-shutdown state of the process memory, about 200 globals change state. Been slowly making progress to get restarts working

New comment by deivid in "Ask HN: What Are You Working On? (December 2025)"

deivid — Mon, 15 Dec 2025 00:11:54 +0000

Building postgres server as a library. Some early success, but initdb and in-process restarts are much harder than expected

New comment by deivid in "Ask HN: Is starting a personal blog still worth it in the age of AI?"

deivid — Mon, 15 Dec 2025 00:07:30 +0000

I've been writing on my blog for 9 years. Still feel the same blockers you do on every new post.

For me, the main motivation is that I enjoy reading other people's blogs, and hopefully my posts give someone ekse a similar enjoyment

I had a few attempts to lower the bar (tags for low effort, short and shitpost so far), but it feels like a crutch and hasn't worked long term for me.

New comment by deivid in "Driving TFEL with RP2040: Offloading the CPU step by step (2021)"

deivid — Sat, 15 Nov 2025 14:00:46 +0000

These screens look amazing, but $1500-2500 is a bit much. Any other screens with this monichrome CRT style?

New comment by deivid in "JetKVM – Control any computer remotely"

deivid — Tue, 28 Oct 2025 07:56:03 +0000

I've had this project idea in my list for a while, I even implemented thr software side (an option rom for the pci card) but the hardware side is quite difficult to get started. My plan was to get an FPGA with a hard pci core to do this, but I don't even know what to buy.

I got a cheap Tang Mega 238k but I never managed to even get the PCI examples working (and couldn't even adjust BAR settings)

New comment by deivid in "An Update on TinyKVM"

deivid — Sun, 26 Oct 2025 17:17:59 +0000

Well it was released on Linux in 2007, so it's meant Kernel Virtual Machine for at least 18 years

See: https://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine