Hey Arun, IIya, the GPUs are faster because of 1. designed for graphics processing, which involves a lot of matrix processing capabilities , simple example transformation of matrices in to various view (projection, model and viewport , some times needed even in real time) so these computation are done in parallel 2. all or most of processing are done at much precise rate and until one does not specify, all are 'double computations' which is quite costly even in modern CPU - ALU 3. not only computations, a lot of other parallel architectural advantage gives normal algorithms ( e.g. cache) better speedup than CPU
hope it clarifies. So if you are planning to start on GPU, start thinking in multi-threaded copying data generally involves separate processing of DMA, I worked with USB and PCI 66MHz connection of CPU/GPU , and does not seem to be slow. even Fujitsu CoralPA was ok which has very slow dma and a PCI 33 connection. On Apr 8, 4:04 am, Ilya Albrekht <ilya.albre...@gmail.com> wrote: > Hey Phoenix, > > It is true that current GPU have way better floating point throughput than > any general purpose processor. But when you want to run your algo. on the > GPU there are always an overhead of copying data between CPU & GPU, drivers > and other system calls and you can gain performance even with those > overhead if you have a lot of calculations (more calculations, less > overhead %). And I assume in general you have to do at least O(n^3) > calculations to gain any perf. > > Out of my experience, the same thigh with the SSE vectorization - it > doesn't make sense to vectorize the loop if it is less than ~25-27 > iterations, because the overhead of preparing data and aligning buffers > will be too high. > > > > > > > > On Saturday, 7 April 2012 08:54:20 UTC-7, phoenix wrote: > > > @SAMM: what about general mathematical computations such as matrix > > multiplication which is O(n^3) as such? How do you relate your explanation > > to such math computations or any algorithm of atleast O(n^3)? > > > On Sat, Apr 7, 2012 at 3:22 AM, SAMM <somnath.nit...@gmail.com> wrote: > > >> This is becoz the GPU is multithreaded . In graphics there are three main > >> steps , Application based work where vertex Processing , read the data , > >> pixel processing are done . > >> Secondly come the Culling which which determimes which portion will be > >> shown given the Line of sight . This also checks for any intersection with > >> other objects . For instance a man is present behind the building ,so he > >> should not be visible to us in Graphics or some portion of this body will > >> be shown , This intersection is called redering . > > >> The third step if draw . to finally draw the model . > > >> These three process are done multithreaded parallerly given 3x Processing > >> speed . > >> You can refer this link below :- > >>http://www.panda3d.org/manual/index.php/Multithreaded_Render_Pipeline > > >> -- > >> You received this message because you are subscribed to the Google Groups > >> "Algorithm Geeks" group. > >> To post to this group, send email to algogeeks@googlegroups.com. > >> To unsubscribe from this group, send email to > >> algogeeks+unsubscr...@googlegroups.com. > >> For more options, visit this group at > >>http://groups.google.com/group/algogeeks?hl=en. > > > -- > > "People often say that motivation doesn't last. Well, neither does > > bathing - that's why we recommend it daily." -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com. To unsubscribe from this group, send email to algogeeks+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
