Messages in this thread | | | From | Perry Harrington <> | Subject | Re: Remote fork() and Parallel programming | Date | Sun, 14 Jun 1998 15:42:44 -0700 (PDT) |
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> > : It seemed wiser to write my software for MPI and deal with the > : difficulties and it being non-optimum on my smp system. (Although I've > : never tested it, I'm sure that shared memory on a smp system is *MUCH* > : faster then MPI)... > > Actually, only if you don't do anything to the MPI libraries. I.e., they > are doing networking through the loopback device. > > SGI took the libs, gutted 'em, leaving just the interfaces, and tuned them > especially for SMP machines (yeah, they can still call out to the networking > ones when they need to). > > They even did some VM hacking such that they could map another process' > address space so that a send() turned into > > find the process associated with the destination > make we've already mapped the destination > bcopy() > > It was damn close to no more than the bcopy() cost.
IIRC, Unix domain sockets are implemented as a memory passing scheme. Since a UDS would conceivably be less resource intensive than actually doing a lookup PID, find the VMA, then copy, perhaps the energy would be better spent optimizing that functionality?
--Perry
-- Perry Harrington Linux rules all OSes. APSoft () email: perry@apsoft.com Think Blue. /\
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