So, there is still some power-law nonlinearity in the tangle code. Benchmarking revealed the following: 8259 95% - org-babel-tangle-file 8259 95% - org-babel-tangle 8170 94% - org-babel-tangle-collect-blocks 3620 41% - org-in-archived-heading-p 3600 41% org-before-first-heading-p Showing that nonlinear scaling comes from regexp search. Caching org-before-first-heading-p improves the performance further (see Org 9.6-dev no self-verify + patch curves): | N blocks | runtime | # of GCs | |----------+---------+----------| | 10 | 0.118 | 0 | | 20 | 0.106 | 0 | | 40 | 0.136 | 0 | | 80 | 0.157 | 0 | | 160 | 0.139 | 0 | | 320 | 0.212 | 0 | | 640 | 0.542 | 0 | | 1280 | 0.797 | 0 | | 2560 | 1.533 | 0 | | 5120 | 4.651 | 0 | | 10240 | 16.745 | 0 | The profiling gives: 16817 63% - org-babel-tangle-file 16280 61% - org-babel-tangle 16200 61% - org-babel-tangle-collect-blocks 1360 5% + org-babel-tangle-single-block 1210 4% + org-babel-get-src-block-info Most of the CPU time is spent in org-babel-tangle-collect-blocks, which is basically another regexp search for all the source blocks in buffer. The scaling is still slightly non-linear - maybe your source block regexp is too complex: (defvar org-babel-src-block-regexp (concat ;; (1) indentation (2) lang "^\\([ \t]*\\)#\\+begin_src[ \t]+\\([^ \f\t\n\r\v]+\\)[ \t]*" ;; (3) switches "\\([^\":\n]*\"[^\"\n*]*\"[^\":\n]*\\|[^\":\n]*\\)" ;; (4) header arguments "\\([^\n]*\\)\n" ;; (5) body "\\([^\000]*?\n\\)??[ \t]*#\\+end_src") "Regexp used to identify code blocks.") On the other hand, the test data is already within quite non-realistic over 5000 number of blocks. Probably, further performance improvement is not very useful (we already have some overheads at smaller N). Best, Ihor ----- The Org file used to generate plots: #+name: nocache | N blocks | runtime | # of GCs | |----------+---------+----------| | 10 | 0.027 | 0 | | 20 | 0.049 | 0 | | 40 | 0.121 | 0 | | 80 | 0.391 | 0 | | 160 | 1.426 | 0 | | 320 | 6.765 | 0 | | 640 | 23.972 | 0 | #+name: cache | N blocks | runtime | # of GCs | |----------+---------+----------| | 10 | 0.030 | 0 | | 20 | 0.067 | 0 | | 40 | 0.065 | 0 | | 80 | 0.081 | 0 | | 160 | 0.214 | 0 | | 320 | 0.597 | 0 | | 640 | 2.225 | 0 | | 1280 | 9.221 | 0 | | 2560 | 36.966 | 0 | #+name: cache-no-self | N blocks | runtime | # of GCs | |----------+---------+----------| | 10 | 0.078 | 0 | | 20 | 0.075 | 0 | | 40 | 0.063 | 0 | | 80 | 0.085 | 0 | | 160 | 0.095 | 0 | | 320 | 0.178 | 0 | | 640 | 0.311 | 0 | | 1280 | 0.819 | 0 | | 2560 | 2.302 | 0 | | 5120 | 8.878 | 0 | | 10240 | 32.706 | 0 | #+name: cache-no-self+fix | N blocks | runtime | # of GCs | |----------+---------+----------| | 10 | 0.118 | 0 | | 20 | 0.106 | 0 | | 40 | 0.136 | 0 | | 80 | 0.157 | 0 | | 160 | 0.139 | 0 | | 320 | 0.212 | 0 | | 640 | 0.542 | 0 | | 1280 | 0.797 | 0 | | 2560 | 1.533 | 0 | | 5120 | 4.651 | 0 | | 10240 | 16.745 | 0 | #+begin_src gnuplot :var d1=nocache :var d2=cache :var d3=cache-no-self :var d4=cache-no-self+fix :file benchmark1.png set title 'Tangle code performance timing' US='u 1:2 w lp ps 2' set xlabel "N blocks" set ylabel "Time, sec" set key top right plot d1 @US t'Org 9.5.2 stable', d2 @US t'Org 9.6-dev', d3 @US t'Org 9.6-dev no self-verify', d4 @US t'Org 9.6-dev no self-verify + patch' #+end_src #+RESULTS[edd2a2d5d80b31876917faee349ed71ba0fe239a]: [[file:/home/yantar92/.data/52/0930af-75ae-4d88-ae6a-d8dde39ecc72/benchmark1.png]] #+begin_src gnuplot :var d1=nocache :var d2=cache :var d3=cache-no-self :var d4=cache-no-self+fix :file benchmark2.png set title 'Tangle code performance scaling (normalized)' US='w lp ps 2' set xlabel "N blocks" set ylabel "Time, normalized by time at N=640" set key top left set xrange [0:6000] plot d2 u 1:($2/2.225) @US t'Org 9.6-dev', d3 u 1:($2/0.311) @US t'Org 9.6-dev no self-verify', d1 u 1:($2/23.972) @US t'Org 9.5.2 stable', d4 u 1:($2/0.542) @US t'Org 9.6-dev no self-verify + patch', x*x/870000 t'x^2', #+end_src #+RESULTS[b170ef78ac377f6d2ad1c2eabb20cd62dc0ea33f]: [[file:/home/yantar92/.data/52/0930af-75ae-4d88-ae6a-d8dde39ecc72/benchmark2.png]]