in the previous mail ,read: It seems again that only with this code Guile Racket can make another thread only when the previous is finished (after touch)...
On Fri, Nov 11, 2022 at 2:36 PM Damien Mattei <damien.mat...@gmail.com> wrote: > Hi Zelphir, > > > On Fri, Nov 11, 2022 at 1:25 PM Zelphir Kaltstahl < > zelphirkaltst...@posteo.de> wrote: > >> >> Note, that threads in Guile and Racket are different: >> >> >> https://docs.racket-lang.org/reference/eval-model.html#%28part._thread-model%29 >> : >> >> > Racket supports multiple threads of evaluation. Threads run >> concurrently, in the sense that one thread can preempt another without its >> cooperation, but threads currently all run on the same processor (i.e., the >> same underlying operating system process and thread). >> > > oh! that is the reason with Racket of no speed up. > > https://www.gnu.org/software/guile/manual/html_node/Threads.html: >> >> > The procedures below manipulate Guile threads, which are wrappers >> around the system’s POSIX threads. For application-level parallelism, using >> higher-level constructs, such as futures, is recommended (see Futures). >> > yes but futures seems to block on touch with guile, the same code under > Racket,do not show speed up, it display a different output: > run-in-parallel : making future > run-in-parallel : touching future > run-in-parallel : making future > run-in-parallel : touching future > run-in-parallel : making future > run-in-parallel : touching future > run-in-parallel : making future > run-in-parallel : touching future > run-in-parallel : making future > run-in-parallel : touching future > run-in-parallel : making future > run-in-parallel : touching future > it is different from the guile ouput. > It seems again that only with this code Guile can make another thread when > the previous is finished (after touch)... > > The code is this one: > > https://github.com/damien-mattei/library-FunctProg/blob/master/racket/logiki%2B.rkt#L3012 > > > https://github.com/damien-mattei/library-FunctProg/blob/master/racket/logiki%2B.rkt#L3331 > > i do not think it could work faster if i cannot access to others CPUs like > in OpenMP > or this: > https://en.wikipedia.org/wiki/Processor_affinity > but it is not existing with Scheme. > > Best Regards, > Damien > >> I believe another word for Racket's threads is "green threads". They are >> like (more like?) Python threads, and do not run on another core. If you >> start multiple Racket threads on the same Racket VM, they will run all on >> the same core. No speedup to be expected, unless you would be waiting for >> IO or something, if you did not use threads. Racket threads are concurrent, >> but not parallel. >> >> I think Racket's threads' nature is the answer to why it is slower than >> single threaded execution. >> >> Regards, >> Zelphir >> >> -- >> repositories: https://notabug.org/ZelphirKaltstahl >> >>
