pennae 34e3bd10e3 avoid copies of parser input data ... when given a string yacc will copy the entire input to a newly allocated location so that it can add a second terminating NUL byte. since the parser is a very internal thing to EvalState we can ensure that having two terminating NUL bytes is always possible without copying, and have the parser itself merely check that the expected NULs are present. # before Benchmark 1: nix search --offline nixpkgs hello Time (mean ± σ): 572.4 ms ± 2.3 ms [User: 563.4 ms, System: 8.6 ms] Range (min … max): 566.9 ms … 579.1 ms 50 runs Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix Time (mean ± σ): 381.7 ms ± 1.0 ms [User: 348.3 ms, System: 33.1 ms] Range (min … max): 380.2 ms … 387.7 ms 50 runs Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system' Time (mean ± σ): 2.936 s ± 0.005 s [User: 2.715 s, System: 0.221 s] Range (min … max): 2.923 s … 2.946 s 50 runs # after Benchmark 1: nix search --offline nixpkgs hello Time (mean ± σ): 571.7 ms ± 2.4 ms [User: 563.3 ms, System: 8.0 ms] Range (min … max): 566.7 ms … 579.7 ms 50 runs Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix Time (mean ± σ): 376.6 ms ± 1.0 ms [User: 345.8 ms, System: 30.5 ms] Range (min … max): 374.5 ms … 379.1 ms 50 runs Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system' Time (mean ± σ): 2.922 s ± 0.006 s [User: 2.707 s, System: 0.215 s] Range (min … max): 2.906 s … 2.934 s 50 runs		2022-01-13 18:06:15 +01:00
..
nix-build.cc	avoid copies of parser input data	2022-01-13 18:06:15 +01:00