Re: [PATCH v2] docs: drop the version constraints for sphinx and dependencies

[Donald Hunter]

On Tue, 19 Mar 2024 at 17:59, Donald Hunter <donald.hunter@xxxxxxxxx> wrote:
>
> > > > I have an experimental fix that uses a dict for lookups. With the fix, I
> > > > consistently get times in the sub 5 minute range:
> > >
> > > Fantastic!
>
> I pushed my performance changes to GitHub if you want to try them out:
>
> https://github.com/donaldh/sphinx/tree/c-domain-speedup

Now a PR: https://github.com/sphinx-doc/sphinx/pull/12162

Following up on the incremental build performance, I have been
experimenting with different batch sizes when building the Linux
kernel docs. My results suggest that the best performance is achieved
by using a minimum batch size of 200 for reads because batches smaller
than that have too high a merge overhead back into the main process. I
also experimented with a minimum threshold of 500 before even
splitting into batches, i.e. if there are less than 500 changed docs
then just process them serially.

With the existing make_chunks behaviour, a small number of changed
docs gives worst case behaviour of 1 doc per chunk. Merging single
docs back into the main process destroys any benefit from the parallel
processing. E.g. running make htmldocs SPHINXOPTS=-j12

Running Sphinx v7.2.6
[...]
building [html]: targets for 3445 source files that are out of date
updating environment: [new config] 3445 added, 0 changed, 0 removed
[...]
real 7m46.198s
user 14m18.597s
sys 0m54.925s

for a full build of 3445 files vs an incremental build of just 114 files:

Running Sphinx v7.2.6
[...]
building [html]: targets for 114 source files that are out of date
updating environment: 0 added, 114 changed, 0 removed
real 5m50.746s
user 6m33.199s
sys 0m13.034s

When I run the incremental build serially with make htmldocs
SPHINXOPTS=-j1 then it is much faster:

building [html]: targets for 114 source files that are out of date
updating environment: 0 added, 114 changed, 0 removed
real 1m5.034s
user 1m3.183s
sys 0m1.616s