----- Original Message ----- From: "Liaw, Andy" <[EMAIL PROTECTED]> To: "'Prof Brian Ripley'" <[EMAIL PROTECTED]>; "Jose Quesada" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Monday, July 26, 2004 9:18 AM Subject: RE: [R] R on AMD64 (Opteron)
> Just one more thing for folks intending to try Opterons with >1 cpu: You'll > probably want to use a NUMA kernel, rather than a SMP one. > > Cheers, > Andy Thanks for the advice, but is there another reason why you write this beside a large (I mean >8) number of CPUs? At http://lse.sourceforge.net/numa/faq/ I read, What is the difference between NUMA and SMP? The NUMA architecture was designed to surpass the scalability limits of the SMP architecture. With SMP, which stands for Symmetric Multi-Processing, all memory access are posted to the same shared memory bus. This works fine for a relatively small number of CPUs, but the problem with the shared bus appears when you have dozens, even hundreds, of CPUs competing for access to the shared memory bus. NUMA alleviates these bottlenecks by limiting the number of CPUs on any one memory bus, and connecting the various nodes by means of a high speed interconnect. ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
