pennae 1fe66852ff reduce the size of Env by one pointer ... since `up` and `values` are both pointer-aligned the type field will also be pointer-aligned, wasting 48 bits of space on most machines. we can get away with removing the type field altogether by encoding some information into the `with` expr that created the env to begin with, reducing the GC load for the absolutely massive amount of single-entry envs we create for lambdas. this reduces memory usage of system eval by quite a bit (reducing heap size of our system eval from 8.4GB to 8.23GB) and gives similar savings in eval time. running `nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'` before: Time (mean ± σ): 5.576 s ± 0.003 s [User: 5.197 s, System: 0.378 s] Range (min … max): 5.572 s … 5.581 s 10 runs after: Time (mean ± σ): 5.408 s ± 0.002 s [User: 5.019 s, System: 0.388 s] Range (min … max): 5.405 s … 5.411 s 10 runs		2023-12-30 18:55:13 +01:00
..
allowed-uris-can-now-match-whole-schemes.md
cgroup-stats.md
config
env-size-reduction.md	reduce the size of Env by one pointer	2023-12-30 18:55:13 +01:00
eval-system.md
hash-format-nix32.md
mounted-ssh-store.md
nix-config-show.md
nix-env-json-drv-path.md
nix-hash-convert.md
nix-profile-names.md	Fix release notes	2023-12-21 16:38:25 +01:00
source-positions-in-errors.md
with-error-reporting.md	reduce the size of Env by one pointer	2023-12-30 18:55:13 +01:00