Since withFramedSink() is now used a lot more than in the past (for
every addToStore() variant), we were creating a lot of threads, e.g.
nix flake show --no-eval-cache --all-systems github:NixOS/nix/afdd12be5e19c0001ff3297dea544301108d298
would create 46418 threads. While threads on Linux are cheap, this is
still substantial overhead.
So instead, just poll from FramedSink before every write whether there
are pending messages from the daemon. This could slightly increase the
latency on log messages from the daemon, but not on exceptions (which
were only synchronously checked from FramedSink anyway).
This speeds up the command above from 19.2s to 17.5s on my machine (a
9% speedup).
This is useful for diagnosing whether an evaluation is copying large
paths to the store. Example:
$ nix build .#packages.x86_64-linux.default --large-path-warning-threshold 1000000
warning: copied large path '/home/eelco/Dev/nix-master/' to the store (6271792 bytes)
warning: copied large path '«github:NixOS/nixpkgs/b550fe4b4776908ac2a861124307045f8e717c8e?narHash=sha256-7kkJQd4rZ%2BvFrzWu8sTRtta5D1kBG0LSRYAfhtmMlSo%3D»/' to the store (155263768 bytes)
warning: copied large path '«github:libgit2/libgit2/45fd9ed7ae1a9b74b957ef4f337bc3c8b3df01b5?narHash=sha256-oX4Z3S9WtJlwvj0uH9HlYcWv%2Bx1hqp8mhXl7HsLu2f0%3D»/' to the store (22175416 bytes)
warning: copied large path '/nix/store/z985088mcd6w23qwdlirsinnyzayagki-source' to the store (5885872 bytes)
This splits files and adds new identifiers in preperation for supporting
windows, but no Windows-specific code is actually added yet.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This is the core functionality but just unit-tested and not yet made
part of the store layer. This is because there is some tech debt around
(a) repeated boilerplate hashing objects (b) better integration of the
new `SourceAccessor` type that needs to be cleaned up first.
Part of RFC 133
Co-Authored-By: Matthew Bauer <mjbauer95@gmail.com>
Co-Authored-By: Carlo Nucera <carlo.nucera@protonmail.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Florian Klink <flokli@flokli.de>
All OS and IO operations should be moved out, leaving only some misc
portable pure functions.
This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.
Newly exposed functions to break cycles:
- `restoreSignals`
- `updateWindowSize`
The `write` name is ambiguous and could lead to some funny bugs like
https://github.com/NixOS/nix/pull/8173#issuecomment-1500009480. So
rename it to the more explicit `writeUnbuffered`.
Besides, this method shouldn't be (and isn't) used outside of the class
implementation, so mark it `protected`.
This makes it more symetrical to `BufferedSource` which uses a
`protected readUnbuffered` method.
Crucially this introduces BoehmGCStackAllocator, but it also
adds a bunch of wiring to avoid making libutil depend on bdw-gc.
Part of the solutions for #4178, #4200
