[Koha-devel] Search speed

[Robin Sheat]

Paul A schreef op do 29-01-2015 om 19:39 [-0500]:
> Facets appear to have a huge overhead in various components of Zebra,
> to 
> the point where a single core of a multiple processor CPU gets
> overwhelmed, 
> but does not share the load with other totally idle cores.

That's not how multiprocessor systems work.

They can only spread load amongst other cores if the software is
multithreaded/multiprocess, which I suspect zebra isn't, at least within
a single request. If it does all its work in a single thread, then it
can't spread across multiple cores.

> Intel tell me 
> that this is not fixable through any hardware/BIOS config and they are
> not 
> aware of a Linux "standard library" that deals with processor 
> affinity.  I've searched around a little and found mentions for c and 
> FORTRAN (marvelous old memories for me!) but so far nothing totally 
> specific for Perl. 

Zebra is not Perl, zebra is (I think) C. But still, unless it's written
with multithreading in mind, you can't do anything about it.
> 
> taskset and sched_setaffinity might be usable at system 
> level

Unless you have very specific use cases (which you don't), these won't
help.
> 
> , and I might have a look at pthread_setaffinity_np.3.gz

That will only help if you plan on rewriting zebra to use pthreads.

I don't recommend rewriting zebra.

-- 
Robin Sheat
Catalyst IT Ltd.
✆ +64 4 803 2204
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