Re: article rescoring during download

Am 22.12.2012 06:54, schrieb [email protected]:
> Hi all,
>
>
> I was curious what the latest pan looked like so I pulled down debian
> unstable (0.139-1).  There was a remarkable slowdown and much higher CPU
> usage when pulling binaries from large groups as compared to 0.133.
>
> I grabbed the latest git code and did a little profiling.  Eventually I
> found a curious call being made in pan/gui/header-pane.cc, line 2527:
>
>   
> void
> HeaderPane :: on_cache_added (const Quark& message_id)
> {
>    quarks_t q;
>    q.insert(message_id);
>    _data.rescore_articles ( _group, q );    // here is slow
>    rebuild_article_action (message_id);
> }
>
>
> That rescore_articles call eventually gets down to a std::set_intersection
> over what I believe to be the entire list of articles in the group of
> interest.
>
> This on_cache_added call is made fairly often, possibly each time an
> article's contents are retrieved.
>
> I couldn't see anything terribly valuable in this call since I don't use
> scoring other than to plonk authors so I commented out the three related
> lines and saw my bandwidth get fully utilized again.
>
>
> As for treating this, the code is doing an intersection with a single
> element set (the one quark), which is effectively a find.  There might be a
> faster find if these articles are already hashed.  I don't know enough
> about the system to suggest a complete new codepath.  There might be a
> "user doesn't use scoring" flag that flat avoids this call.
>
>
>
>
>
>                                    Eric Ortega
>
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Thanks for noticing this bug, I'll fix it.

Cheers.