[tbb-dev] Very very slow tor-browser-build build; catastrophic recursion in rbm?

[Nicolas Vigier]

On Tue, 11 Feb 2020, David Fifield wrote:

> 
> To my untrained eye it looks like there is some kind of exponential
> recursion happening around the RBM::config_p function. See here, where
> in building one project the function was called 89 million times:
> https://people.torproject.org/~dcf/graphs/nytprof-rbm-20200212-94fce31e/#subs_table
> Clicking through to the per-line view, we see that 45 million of those
> calls were from RBM::get_target, and most of the rest were from
> RBM::config:
> https://people.torproject.org/~dcf/graphs/nytprof-rbm-20200212-94fce31e/root-tor-browser-build-rbm-lib-RBM-pm-8-line.html#89

After looking at this more closely, I am expecting RBM::config_p to be
called a lot of times (although maybe not 89 millions times), but I
would not expect that more than half of this would be from RBM::get_target.

So I opened an other ticket about that:
https://trac.torproject.org/projects/tor/ticket/33289