mt@cleo.cs.wisc.edu (Manolis Tsangaris) (03/09/90)
Is there a port going on? I saw nothing about the (IPSC/2) Hypercube, in the recent MACH newsletter. It seems that MACH expects a uniform and equally accessible by all processors physical memory (pmap interface). People at Rochester have used the pmap interface to support Non Uniform Access Memory (The ACE multiprocessor and the Butterfly), but IPSC/2's memory is completely partitioned among the processors (i.e. every memory module is local to each processor). Since IPSC/2 is a "shared nothing" multiprocessor, is it advisable to run a single MACH kernel over its 32 (or less) processors? The alternative solution would be to treat hypercube as a super fast distributed system, with one MACH kernel per processor. But this would make expensive things like task migration (how about TLB consistency!). --mt
jerbil@cit-vax.Caltech.Edu (Joseph Beckenbach) (03/09/90)
In his article Manolis Tsangaris <mt@cleo.cs.wisc.edu> writes: >Since IPSC/2 is a "shared nothing" multiprocessor, is it advisable to run a >single MACH kernel over its 32 (or less) processors? The alternative solution >would be to treat hypercube as a super fast distributed system, with one MACH >kernel per processor. But this would make expensive things like task migration >(how about TLB consistency!). The only two sensible things to seem to be to place one instance of the MACH kernel on each node and act as if they were on a single private network, or to combine several nodes with some form of shared memory emulator (an external pager?) and work from there. For anything smaller than 4MB I can see no alternatives -- someone care to enlighten us further? [I had enquired about hypercubes running MACH when I attended the MACH tutorials at the Winter 1990 USENIX; Tevanian and Nawar both seemed to think that placing MACH on hypercubes would be an interesting exercise and little more -- I may have misinterpreted.] Joe Beckenbach -- Joe Beckenbach jerbil@csvax.caltech.edu VEGGIES FOREVER! Toto, kansasoseum nun est cognito. -- Farley