pareto optimal <pareto.opti...@mailfence.com> writes:
> Using =emacs -Q= to tangle org files with more than over 100 noweb-refs gets
> slow fast.
>
> Given this org code for N=2:
> Using Gcc Emacs 28.0.91 (which I typicall use) I get these results:
>
> | 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 |
>
> so roughly it scales like:
>
> #+begin_example
> 0.8x (10-20)
> 2.5x (20-40)
> 3x (40-80)
> 3.5x (160-320)
> 4x (320-640)
> #+end_example
>
> Though I'm not sure how much that can tell us... my guess is noweb-ref's
> don't use a dictionary with =O(1)= lookups?
Thanks for the nice benchmark and for providing a test case!
You are using stable version of Org. We did some important performance
improvements on main. The same benchmark using latest main (26decec):
| 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 |
And with disabled self-verification code:
(setq org-element--cache-self-verify nil)
| 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 |
Graphical comparison:
There is ~80x improvement.
However, the scaling is still not quite linear:
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]]
