On Thursday, November 05, 2015 01:34:02 PM hw wrote: > J. Roeleveld wrote: > > On 4 November 2015 13:14:18 CET, hw <h...@gc-24.de> wrote: > >> Hi, > >> > >> how do I know whether xen uses NUMA or not? It says in dmesg: > >> > >> > >> [ 0.000000] NUMA turned off > >> [ 0.000000] Faking a node at [mem > >> 0x0000000000000000-0x0000000040068fff] > >> > >> > >> and 'xl info -n' shows two nodes: > >> > >> > >> node: memsize memfree distances > >> > >> 0: 14656 3304 10,20 > >> 1: 23424 7792 20,10 > >> > >> which could be right --- though I would expect each node to have 12GB > >> rather than these weird sizes. > >> > >> So is NUMA turned off or not? Is it even possible to turn it off when > >> it's > >> enabled in the BIOS? > > > > If BIOS has it enabled. Then the OS still beeds to support it. > > > > Recent Xen has support for it. > > Is there any way to find out if it's actually made use of?
Yes, you might want to read the Xen documentation: http://wiki.xen.org/wiki/Xen_on_NUMA_Machines > > As for the non uniform spread of the memory. It depends how the memory > > modules are placed in the mainboard with regards to the Numa nodes. (CPU) > The memory is evenly spread. The server has two CPUs with 6 memory banks > each. All banks for each CPU are loaded identically. Hence two NUMA nodes > would make sense, and each of them should see/have 12GB (now 14 each > because I changed out the server because it kept crashing/freezing/becoming > unreachable even after the software updates). Is this according to the actual manual? Or based on what the mainboard looks like? -- Joost
