[Koha-devel] Search speed

[Paul A]

At 04:53 PM 1/30/2015 -0500, Mark Tompsett wrote:
>Greetings,
>
>If there is no negative effect, and only positive effects, I'd be more 
>than willing to submit a patch to default with a -T. :)

I'm looking for "negatives" right now. Give me another little while, and 
I'll do a bug/enhancement myself with all the numbers (a bit of a struggle, 
NYTProf doesn't appear to like multi-threading.)

Best -- Paul


>GPML,
>Mark Tompsett
>
>-----Original Message----- From: Paul A
>Sent: Friday, January 30, 2015 3:19 PM
>To: Fridolin SOMERS ; koha-devel at lists.koha-community.org
>Subject: Re: [Koha-devel] Search speed
>
>At 05:40 PM 1/30/2015 +0100, Fridolin SOMERS wrote:
>>You can launch Zebra multi-threaded using :
>>zebrasrv -T
>
>Fridolin - merci mille fois -- first impressions are most positive.  I'll
>try and find time later today to quantify the results and put them in
>context of my previous tests.
>
>[vi /usr/share/koha/bin/koha-zebra-ctl.sh line 40 to ZEBRAOPTIONS="-T -v
>none,fatal,warn"]
>
>J'aurais bien aimer trouver ça tout seul ... mais encore une fois avec mes
>remerciments.
>
>Meilleures amitiés et a+
>Paul
>
>
>>Le 30/01/2015 02:59, Robin Sheat a écrit :
>>>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.
>>>
>>>
>>>
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>>
>>--
>>Fridolin SOMERS
>>Biblibre - Pôles support et système
>>fridolin.somers at biblibre.com
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>
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---
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<http://NavalMarineArchive.com> and <http://UltraMarine.ca>