glad I could help, https://github.com/wellposed/hblas/blob/master/src/Numerical/HBLAS/BLAS/Internal.hs#L146 is an example of the "choose to do the safe vs unsafe ffi call" trick in the case of blas / lapack routines, i can always estimate how long a compute job will take as a function of its inputs, and i use that estimate to decide which ffi strategy to use (ie i use unsafe ffi on < 10 microsecond computations so that the overhead doesn't dominate the compute time on tiny inputs)
On Thu, Aug 14, 2014 at 5:38 PM, Christian Höner zu Siederdissen < choe...@tbi.univie.ac.at> wrote: > That's actually a great idea, especially since the safe variants of the > calls are already in place. > > * Carter Schonwald <carter.schonw...@gmail.com> [14.08.2014 23:10]: > > have a smart wrapper around you ffi call, and if when you think the > ffi > > call will take more than 1 microsecond, ALWAYS use the safe ffi call, > > i do something like this in an FFI i wrote, it works great > > > > On Thu, Aug 14, 2014 at 1:20 PM, Christian HAP:ner zu Siederdissen > > <choe...@tbi.univie.ac.at> wrote: > > > > Thanks, > > > > I've played around some more and finally more than one capability is > > active. And indeed, unsafe calls don't block everything. I /had/ > > actually read that but when I saw the system spending basically only > > 100% cpu time, I'd thought to ask. > > > > One problem with this program seems to be that the different tasks > are > > of vastly different sizes. Inputs range from ~ 7x10^1 to ~ 3x10^7 > > elements inducing waits with the larger problem sizes. > > > > We'll keep the program single-threaded for now as this also keeps > memory > > consumption at only 25 gbyte instead of the more impressive 70 > gbyte in > > multi-threaded mode ;-) > > > > Viele Gruesse, > > Christian > > > > _______________________________________________ > > Glasgow-haskell-users mailing list > > Glasgow-haskell-users@haskell.org > > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users >
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