Jeff Hammond <[email protected]> writes: > OpenMP did not prevent OpenCL,
This programming model isn't really intended for architectures with persistent caches. > C11, C++11 These are basically pthreads, which predates OpenMP. > or Fortran 2008 A different language and doesn't play well with others. > from introducing parallelism. Not sure if your comment was meant to be > serious, Partially. It was just enough to give the appearance of a solution while not really being a solution. > but it appears unfounded nonetheless. > > Jeff > > On Sun, Mar 12, 2017 at 11:16 AM Jed Brown <[email protected]> wrote: > >> Implementation-defined, but it's exactly the same as malloc, which also >> doesn't promise unfaulted pages. This is one reason some of us keep saying >> that OpenMP sucks. It's a shitty standard that obstructs better standards >> from being created. >> >> >> On March 12, 2017 11:19:49 AM MDT, Jeff Hammond <[email protected]> >> wrote: >> >> >> On Sat, Mar 11, 2017 at 9:00 AM Jed Brown <[email protected]> wrote: >> >> Jeff Hammond <[email protected]> writes: >> > I agree 100% that multithreaded codes that fault pages from the main >> thread in a NUMA environment are doing something wrong ;-) >> > >> > Does calloc *guarantee* pages are not mapped? If I calloc(8), do I get >> the zero page or part of the arena that's already mapped that is zeroed by >> the heap manager? >> >> Is your argument that calloc() should never be used in multi-threaded code? >> >> >> I never use it for code that I want to behave well in a NUMA environment. >> >> >> If the allocation is larger than MMAP_THRESHOLD (128 KiB by default for >> glibc) then it calls mmap. This obviously leaves an intermediate size >> that could be poorly mapped (assuming 4 KiB pages), but it's also so >> small that it easily fits in cache. >> >> >> Is this behavior standardized or merely implementation-defined? I'm not >> interested in writing code that assumes Linux/glibc. >> >> Jeff >> >> >> -- >> Jeff Hammond >> [email protected] >> http://jeffhammond.github.io/ >> >> -- > Jeff Hammond > [email protected] > http://jeffhammond.github.io/
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