| 2 May 2026 |
 Gaétan Lepage | Merged, thanks! | 22:43:36 |
| 5 May 2026 |
|  @gdesforges:matrix.org left the room. | 10:45:13 |
| 7 May 2026 |
|  Amine joined the room. | 14:01:25 |
| 9 May 2026 |
|  tfc joined the room. | 20:55:50 |
| 10 May 2026 |
 neobrain | CUDA-enabled firefox/thunderbird builds are normally supposed to be part of the flox cache, right? | 17:55:51 |
 hexa | we lack introspection into the flox cache | 18:07:38 |
| hexa | I doubt it's getting much use | 18:07:44 |
| hexa | nixos-cuda.org otoh works fairly well | 18:08:00 |
| hexa | the primary question around nixos-cuda.org is sustainability | 18:09:04 |
| neobrain | nice, I'll try moving to that later: https://hydra.nixos-cuda.org/build/369104#tabs-buildinputs | 18:11:33 |
| neobrain | it's surprising to me how difficult most nix caches are to use effectively when you're not able to see which packages are cached to begin with (and in which specific versions) | 18:13:37 |
| hexa | yeah, I mean you don't know whether they're trackin the branch you are using | 18:14:23 |
| hexa | or if they are uptodate on that branch | 18:14:29 |
| hexa | for the flox cache they are trracking their nixpkgs fork, not upstream nixpkgs | 18:14:55 |
| hexa | and they have their own branches and rules how they propagate from branch to branch | 18:15:18 |
| neobrain | yeah I already tried changing my nixpkgs input to follow flox's, so who knows what's wrong 🤷 | 18:16:13 |
 tomberek | This has been a long-standing problem, how to track what is cached and the pins. The underlying issue is that it makes the caches a critical component of the publishing process, not just an optimization. One approach is to encode this into "fake derivations" that promise to be substitutable (eg: via fetchClosure or similar mechanisms).
The issue with your attempt on the flox cache is using the wrong nixpkgs. Are you tracking one of the "stable"/"unstable" branches at https://github.com/flox/nixpkgs/tree/stable ? | 18:23:30 |
| Gaétan Lepage | We (nixos-cuda.org) build all nixpkgs packages with cudaSupport = true (as long as the hash differs from the non-cudaSupport version).
Our jobsets are publicly available here. | 19:26:07 |
| Gaétan Lepage | Having said that, the cache.nixos-cuda.org binary cache is not meant to be consumed by the general public. NVIDIA restricts how certains packages should not be distributed after being patched. This cache is a development resource for the cuda team members.
Flox is the only nix-related entity allowed to redistribute those packages.
https://github.com/nixos-cuda/infra?tab=readme-ov-file#binary-cache | 19:28:17 |
| Gaétan Lepage | * Having said that, the cache.nixos-cuda.org binary cache is not meant to be consumed by the general public. NVIDIA restricts the redistribution of certain packages after having been patched. This cache is a development resource for the cuda team members.
Flox is the only nix-related entity allowed to redistribute those packages.
https://github.com/nixos-cuda/infra?tab=readme-ov-file#binary-cache | 19:29:14 |
| Gaétan Lepage | * Having said that, the cache.nixos-cuda.org binary cache is not meant to be consumed by the general public. NVIDIA restricts the redistribution of certain packages after having been patched. This cache is a development resource for the nix cuda team members.
Flox is the only nix-related entity allowed to redistribute those packages.
https://github.com/nixos-cuda/infra?tab=readme-ov-file#binary-cache | 19:29:55 |
| neobrain | yes, I'm using nixpkgs.url = "github:flox/nixpkgs/unstable" in my flake inputs | 20:24:10 |
| neobrain | I just remembered that nixos-cuda.org doesn't do aarch64 yet, so I can't give it a try after all :( | 20:25:01 |
| hexa | does flox do aarch64-linux??/ | 20:48:54 |
| hexa | Redacted or Malformed Event | 20:48:56 |
| hexa | I'd say right now the problem is that renting aarch64-linux for cheap is not really possible | 20:49:27 |
| neobrain | Ah! nixos-dgx-spark overrides nixpkgs.config.cudaCapabilities in an attempt to improve compile times, but then the side effect of it is that the slim configuration isn't cached by flox. Resetting the variable gives me cache hits again | 20:50:21 |
| neobrain | Yup they do | 20:50:34 |
| neobrain | yeah that makes sense :( | 20:51:39 |
 Robbie Buxton | In reply to @hexa:lossy.network
I'd say right now the problem is that renting aarch64-linux for cheap is not really possible I don’t think it’s too bad in hyper scalers (graviton isn’t bad) not sure about other places tho | 20:54:26 |
