I think that we will have a very great speedup if each thread can have its own Triangulation. Just by parallelizing the loop in RN_DATA::recalculate() but going sequentially with one Triangulation, I still have ~25% gain in calculation time.
On Wed, Jan 22, 2014 at 2:59 PM, Maciej Sumiński <maciej.sumin...@cern.ch>wrote: > Hi Carl, > > Thank you for putting efforts to boost the performance of the ratsnest. > The function is brought by an external library (http://www.sintef.no/ > Projectweb/Geometry-Toolkits/TTL/), I am not sure what is exactly inside. > The expected output should be a Delaunay triangulation of all nodes that > are taken into account while computing ratsnest. > The only issue I am aware of, is the function does not handle well empty > containers, but it should not be the case right now. > > Now, when I looked again to the source code, RN_DATA is derived after > hed::Node class (include/ttl/halfedge/hetriang.h), which contains a > static field. Another thing is (I believe this is the main source of > troubles) static hed::Triangulation (include/ttl/halfedge/hetraits.h:73). > Sorry that I did not say about that before, but I have just discovered > that it is done that way. I will try to change it, but unfortunately there > are little chances that I manage to do that before Sunday. > > Regards, > Orson > > > > On 01/22/2014 06:08 PM, Carl Poirier wrote: > >> Maciej, >> >> Can you summarize to me how the function "Triangulation::createDelaunay( >> nodes.begin(), nodes.end() )" works, and what are the data structures >> involved? >> >> I believe there are some dependencies in there. >> >> >> On Tue, Jan 21, 2014 at 4:05 PM, Cirilo Bernardo >> <cirilo_berna...@yahoo.com <mailto:cirilo_berna...@yahoo.com>> wrote: >> >> >________________________________ >> > From: Carl Poirier <carl.poirie...@gmail.com >> <mailto:carl.poirie...@gmail.com>> >> >To: Marco Serantoni <marco.serant...@gmail.com >> <mailto:marco.serant...@gmail.com>> >> >Cc: Kicad Developers <kicad-developers@lists.launchpad.net >> <mailto:kicad-developers@lists.launchpad.net>> >> >> >Sent: Wednesday, January 22, 2014 3:51 AM >> >Subject: Re: [Kicad-developers] Net names and net codes >> > >> > >> > >> >There are some things in the code that don't like being >> multithreaded. If I parallelize the for loop in >> RN_DATA::Recalculate( int aNet ), I get a segfault. It does not >> happen if I put a lock to the call updateNet( i ), but obviously >> there is no increase in performance. I'm trying to find out what's >> the problem now. >> > >> > >> > >> This sounds to me like data is being altered by different threads >> and possibly there is some memory reallocation happening (growing >> arrays, etc). Locks are only needed when there is contention >> somewhere and of course locks should only be held for as short as >> needed. Another pitfall with threading is that some variables may >> need to be declared 'volatile' if they can be altered in another >> thread while one function is executing. For example, let's say the >> variable 'bool someX' can be altered in 2 threads; something like >> this can happen: >> >> 1. FunctionA starts, and runs a loop while(!someX) { ... } >> 2. FunctionB sets 'someX' to 'true' >> 3. FunctionA continues to run the loop, which is not the intended >> behavior >> >> Of course similar things can happen when using shared memory and >> forked processes. >> >> Threading has other problems to watch out for - for example, are >> there any static variables in functions? If so then you simply >> cannot thread those functions without locks. >> >> - Cirilo >> >> >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~kicad-developers >> Post to : kicad-developers@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~kicad-developers >> More help : https://help.launchpad.net/ListHelp >> >> >
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