On Tue, Jun 06, 2006 at 10:12:33AM +0200, Francesco Pietra wrote: > After the installation of amd64 etch with generic kernel, I chose a kernel > for > multi dual opteron. > uname -a reports: > Linux debian 2.6.15-1 amd64-k8-smp # SMP > > In view of compilation, I I wonder about the following: > > Dual (or more) Opteron designs are not SMP (Symmetric Multi Processor), but > NUMA (Non-Uniform Memory Architecture). With SMP the two CPUs share the same > bus to memory, but with NUMA each CPU hassome local memory connected to a > local memory bus. The other CPU can still get to that memory, but it's a bit > slower. If you would only putin 1x 2GB, you will severely slow down the other > CPU cause it has to go through the other CPU to do memory accesses. See > ftp://ftp.tyan.com/datasheets/d_s2895_101.pdf > The cpu design may have a bearing for the compilation of programs for > multiprocessor systems, like mpqc (in the compilation notes, mpqc refers > to "symmetric multiprocessor", see > http://www.mpqc.org/mpqc-snapshot-html/compile.html.
They _are_ SMP. Every processor is identical and of the same speed. The fact memory access speed is not symetric doesn't mean the CPUs aren't. > Do smp specified on kernel and NUMA for the opteron characteristics fit > together? I can imagine that SMP specified on the kernel chosen simply refers > to the presence of more than one dual-opteron. Anyway, it is a bit confusing > because it might be seen in conflict with the NUMA characteristics of > opteron. SMP simply refers to more than one cpu thread/core/whatever executes code. Intel's hyper threading, dual core, multiple processors, all require SMP. > If it is a silly question, I beg pardon. Not silly. It is getting somewhat confusing. Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]