[fpc-pascal] Threading vs Parallelism ?
Hello. Some developers treat me as dinosaur because I use threads in place of doing parallelism. Huh, ok, but why parallelism is better and how to do it with fpc ? Thanks. Fre;D - Many thanks ;-) -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Threading-vs-Parallelism-tp5728018.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
Hi, On 29/3/2017 9:57 μμ, fredvs wrote: Hello. Some developers treat me as dinosaur because I use threads in place of doing parallelism. Huh, ok, but why parallelism is better and how to do it with fpc ? a nice article I've found long ago when I was researching the same topic "Threading/Concurrency vs. Parallelism" is the following : http://tutorials.jenkov.com/java-concurrency/concurrency-vs-parallelism.html and I tried the multithreadprocslaz package in Lazarus : http://wiki.freepascal.org/Parallel_procedures Happy coding Regards, -- Dimitrios Chr. Ioannidis ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
On Wed, 29 Mar 2017, Dimitrios Chr. Ioannidis via fpc-pascal wrote: Hi, On 29/3/2017 9:57 μμ, fredvs wrote: Hello. Some developers treat me as dinosaur because I use threads in place of doing parallelism. Huh, ok, but why parallelism is better and how to do it with fpc ? a nice article I've found long ago when I was researching the same topic "Threading/Concurrency vs. Parallelism" is the following : http://tutorials.jenkov.com/java-concurrency/concurrency-vs-parallelism.html and I tried the multithreadprocslaz package in Lazarus : http://wiki.freepascal.org/Parallel_procedures Showing nicely that parallelism in a single process implies threads. I would not pay too much attention to what these developers are saying. Michael.___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
Hi, On 29/3/2017 11:15 μμ, Michael Van Canneyt wrote: < snip > Showing nicely that parallelism in a single process implies threads. I would not pay too much attention to what these developers are saying. besides hardware parallelism, how software parallelism ( in the sense of true simultaneous execution ) in a single process without using ( OS dependent ) threads can be achieved ? regards, -- Dimitrios Chr. Ioannidis ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
> I would not pay too much attention to what these developers are saying. Excellent idea, I will do the same ;-) > how software parallelism ( in the sense of true simultaneous execution ) > in a single process without using ( OS dependent ) threads can be achieved > ? Huh, it is exactly was I do not understand... Thanks. Fre;D - Many thanks ;-) -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Threading-vs-Parallelism-tp5728018p5728022.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
> besides hardware parallelism, Is it possible, with fpc, to assign one processor (if multi) for a thread and say to the system to use this one only for the thread ? But maybe it will gives more problems than solutions. Fre;D - Many thanks ;-) -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Threading-vs-Parallelism-tp5728018p5728023.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
Hi, On Wed, 29 Mar 2017, fredvs wrote: > > besides hardware parallelism, > > Is it possible, with fpc, to assign one processor (if multi) for a > thread and say to the system to use this one only for the thread ? But > maybe it will gives more problems than solutions. Yes, it's called thread/process affinity, and most operating systems have a specific API for it. But one should treat such things extremely carefully, otherwise with badly designed data access concurrency you end up with potentially hard to identify structural problems like false sharing (see Wikipedia on this) and others. This can be especially bad for for example on NUMA architectures, or others, where data storage locality to a given core is not obvious. (Just think about clusters, etc.) In other words, as the OS knows best your hardware's layout and how it can best provide performance, energy, bandwith, etc, it's usually very wise to rely on the OS to solve the thread to CPU core assignments for you. Bottom line: parallelism and threading is a very complex problem and very diverse area, and anyone laughing at any approach is just shows how little they know about true depth of the whole topic, IMO. Thinking about any technical solution, or way of implementation as a silver bullet for everything is a very "expert beginner" approach. My 2 cents. Charlie ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
@Karoly Balogh (Charlie/SGR) Perfect, I have now all the arguments to defend the "Dinosaur Threading" choice. Thanks. Fre;D - Many thanks ;-) -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Threading-vs-Parallelism-tp5728018p5728025.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
Parallelism is what hipster Node programmers do, threads are everything else. /jk -- Ryan (ライアン) Yoko Shimomura > ryo (supercell/EGOIST) > Hiroyuki Sawano >> everyone else http://refi64.com On Mar 29, 2017 1:57 PM, "fredvs" wrote: > Hello. > > Some developers treat me as dinosaur because I use threads in place of > doing > parallelism. > > Huh, ok, but why parallelism is better and how to do it with fpc ? > > Thanks. > > Fre;D > > > > - > Many thanks ;-) > -- > View this message in context: http://free-pascal-general. > 1045716.n5.nabble.com/Threading-vs-Parallelism-tp5728018.html > Sent from the Free Pascal - General mailing list archive at Nabble.com. > ___ > fpc-pascal maillist - fpc-pascal@lists.freepascal.org > http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Threading vs Parallelism ?
> On Mar 30, 2017, at 4:25 AM, fredvs wrote: > >> >> how software parallelism ( in the sense of true simultaneous execution ) >> in a single process without using ( OS dependent ) threads can be achieved >> ? > > Huh, it is exactly was I do not understand... Look at an OpenCL tutorial for more information. If you select a CPU device (instead of a GPU device with hundreds of compute units) then the API will automatically allocate the amount of threads available on the all cores available (which may be only 2). It’s still threaded but scales easily depending on the task. I don’t know why but I got the OpenCL CPU target to process multiple times faster than just using the CPU directly. Parallelism is only helpful if you have a problem involving massive amounts of discrete tasks which are part of larger task and can be designed as such. If your problem is designed like this then you can offload the processing to the GPU and get some serious performance benefits. The catch is that reading/writing memory to the GPU is slow so unless you’re processing on large batches of data you’ll spend more time accessing memory than processing. Regards, Ryan Joseph ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Delphi RTTI vs Free Pascal RTTI
2017-03-25 5:40 GMT-03:00 Sven Barth via fpc-pascal < fpc-pascal@lists.freepascal.org>: > Am 24.03.2017 19:55 schrieb "Michael Van Canneyt" >: > > > > > > > > On Fri, 24 Mar 2017, African Wild Dog wrote: > > > >> Hello, > >> > >> I need to write a code compatilble with both free pascal and delphi > using > >> the old style RTTI. > >> What are the diferences between delphi's and free pascal's > approach/types? > >> > >> I took a look at delphi's and fpc's TypInfo unit and it looks like the > >> types/functions are compatible. > > > > > > They are. There is one dereference on Delphi which is not present in fpc, > > although in fpc trunk, this additional dereference is there. If you use > the > > standard functions you should not notice this. > > The binary data of RTTI added before 3.1.1 now has the double indirection, > but the Delphi-compatible "field" names have only a single indirection for > backwards compatibility (they are properties to the double indirection > fields). RTTI data added in 3.1.1 only has the double indirection. > So this difference needs to be kept in mind and will always result in > ifdefs for RTTI code that handles both Delphi and FPC. > > Regards, > Sven > > Thanks for the clarifications. Regards ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
[fpc-pascal] Critical Section and Recursive Calls
Hello, I'm writing a function protected by a critical section which can have recursive calls under certain conditions. Using the TCriticalSection class, after my thread acquires a critical section, if my thread make 6 additional calls to TCriticalSection.Enter, to release the critical section my thread will have to make 6 additional calls to TCriticalSection.Leave? If so, is this behaviour the same on all platforms? >From the Windows API: *"After a thread has ownership of a critical section, it can make additional calls to EnterCriticalSection or TryEnterCriticalSection without blocking its execution. This prevents a thread from deadlocking itself while waiting for a critical section that it already owns. The thread enters the critical section each time EnterCriticalSection and TryEnterCriticalSection succeed. A thread must call LeaveCriticalSection once for each time that it entered the critical section."* Regards ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
[fpc-pascal] Questions About Constructors
Hello, 1 - What happens if my constructor raise an exception? Is my destructor automatically called? 2 - Are the class fields automatically initialized to Default(T) just like in Delphi? Regards ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
