Does Ada tasking profit from multi-core cpus?
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From: jpluto on 4 Mar 2007 12:54 Has someone experience with Ada tasking (especially GNAT) on multi-core systems? Show programs with several working tasks a performance boost on dual-core or quad-core cpus? _________________________________________________________________ Find what you need at prices you�ll love. Compare products and save at MSN� Shopping. http://shopping.msn.com/default/shp/?ptnrid=37,ptnrdata=24102&tcode=T001MSN20A0701
From: Ludovic Brenta on 5 Mar 2007 05:08 "Â jpluto" wrote: > Has someone experience with Ada tasking (especially GNAT) on multi-core > systems? > > Show programs with several working tasks a performance boost on dual-core or > quad-core cpus? On my dual-core Turion 64 with Debian GNU/Linux and GCC 4.1.2, all is well. Ada programs using tasking use both cores. I think it would work on most other platforms too, but YMMV. -- Ludovic Brenta.
From: Dmitry A. Kazakov on 5 Mar 2007 08:12 On 5 Mar 2007 02:08:22 -0800, Ludovic Brenta wrote: > "� jpluto" wrote: >> Has someone experience with Ada tasking (especially GNAT) on multi-core >> systems? >> >> Show programs with several working tasks a performance boost on dual-core or >> quad-core cpus? > > On my dual-core Turion 64 with Debian GNU/Linux and GCC 4.1.2, all is > well. Ada programs using tasking use both cores. I think it would work > on most other platforms too, but YMMV. Apart from using both cores, does anybody know how protected objects function on multi-cores? Especially: 1. Whether protected object's functions are indeed executed concurrently when come from the tasks running on different cores? 2. What are the times required to take/release the protected object's spin lock compared to ones on single core? 3. Can a task switch cores? If yes, what is the overhead of switching? -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de
From: Jeffrey R. Carter on 5 Mar 2007 13:46 jpluto wrote: > > Has someone experience with Ada tasking (especially GNAT) on multi-core > systems? > > Show programs with several working tasks a performance boost on > dual-core or quad-core cpus? This has been discussed more than once. A search at groups.google.com should find those for you. GNAT certainly distributes tasks across multiple cores. -- Jeff Carter "If you think you got a nasty taunting this time, you ain't heard nothing yet!" Monty Python and the Holy Grail 23
From: tmoran on 6 Mar 2007 00:33
> 1. Whether protected object's functions are indeed executed concurrently > when come from the tasks running on different cores? A quick test with a single protected object containing a single, long-duration, function appears to have just one call of the function active at a time, even if the function is called from two different tasks. global_flag : integer := 0; protected body pt is function f(id : integer) return natural is change_count : natural := 0; begin global_flag := id; for i in 1 .. 10_000_000 loop if global_flag /= id then change_count := change_count; global_flag := id; end if; end loop; return change_count; end f; end pt; One task calls pt.f(id=>1) and the other calls pt.f(id=>2). They both get a result of zero back from their function call. This was with Gnat 3.15p Windows 2000 on a dual core Pentium. If I change it from a single protected object to two instances of a protected type, then the function calls are overlapped and return non-zero results. > 3. Can a task switch cores? If yes, what is the overhead of switching? By "switch cores" do you mean that the particular hardware stack pointers swap which stack they are pointing to? I think this is an OS question and, for Windows, I don't know how one asks "which core am I currently running on" - or indeed if that questions makes any sense. |