Comment by kouteiheika 2 days ago
It's not a workaround; it's the most sane way of shipping such software. As long as the builds are reproducible there's nothing wrong with shipping binaries by default, especially when those binaries require non-trivial dependencies (the whole CUDA toolchain) to build.
There's a reason why even among the most diehard Linux users very few run Gentoo and compile their whole system from scratch.
I thought about fixing Flash Attention too so that I don't have to recompile it every time I update Python or pytorch (it's the only special snowflake dependency that I need to manually handle), but at the end of the day it's not that much of a pain to justify the time investment.
If I'm going to invest time here then I'd rather just write my own attention kernels and also do other things which Flash Attention currently doesn't do (8-bit and 4-bit attention variants similar to Sage Attention, and focus on supporting/optimizing primarily for GeForce and RTX Pro GPUs instead of datacenter GPUs which are unobtanium for normal people).
I usually think the same way, and I bet a lot of people do which is why its still broken. But I've finally decided it's never going away completely and it's time to just fix it.
I agree with you that binary distribution is a perfectly reasonable adjunct to source distribution and sometimes even the more sensible one (toolchain size, etc).
In this instance the build is way nastier than building the NVIDIA toolchain (which Nix can do with a single line of configuration in most cases), and the binary artifacts are almost as broken as the source artifact because of NVIDIA tensor core generation shenanigans.
The real answer here is to fucking fork flash-attn and fix it. And it's on my list, but I'm working my way down the major C++ packages that all that stuff links to first. `libmodern-cpp` should be ready for GitHub in two or three months. `hypermodern-ai` is still mostly a domain name and some scripts, but they're the scripts I use in production, so it's coming.