Laura, it turned out to be a core counting bug (in code which is used only on Linux), it got things wrong on such big systems, effectively it counted only one socket. Slipped through for a while, but was fixed shortly after 4.3.6 went out, so will be in 4.3.8 (no release date known).
"VBoxManage list hostinfo" and the /proc/cpuinfo details made this quite clear... Klaus On 30.01.2014 20:17, Klaus Espenlaub wrote: > Hi Laura, > > On 30.01.2014 16:55, Baxter, Laura wrote: >> Hi, >> >> I'm running VirtualBox version 4.3.6 r91406. >> >> The basic problem I am having is that although my (Linux) server has >> 64 CPUs, (4 nodes each with 16 CPUs/8cores with 2 threads per core), >> my VM is only allowing me to set 8 processors (max). > VirtualBox can definitely deal with multi-socket systems (has been > tested on 8 socket systems with 10 cores with 2 threads per core), so we > need to get a bit more detail about the reality (the output of "cat > /dev/cpuinfo") and what VirtualBox thinks (the output of "VBoxManage > list hostinfo"), as the combination will give us a lot of hints what > information might be wrong. lscpu is a very useful command to get a > quick overview, but we need the lower level details. Actually the lscpu > output you provided somewhat contradicts your claims above, you have a > system with 8 nodes with 8 cores each - AMD doesn't do hyperthreading. >> My question is, how can i get my VM to "see" all 64 nodes, to increase >> the VM's processing power? > Careful with the assumption "more VCPUs = faster VM" - even if the > workload on real hardware scales very well, it might be different in a > VM, as the I/O overhead is much higher, and the cross-VCPU > synchronization can be extremely expensive. >> Is this an issue with NUMA not being supported/implemented? > NUMA as such isn't supported (as far as optimizing memory placement is > concerned), but VirtualBox should definitely be able to use all CPUs and > the entire memory. >> Below are some details of the VM and the server, I hope someone has >> some ideas to help, i wonder if this issue affects other users? > We should be able to figure out what's going on... it's definitely not > affecting everyone (and as you're using Linux it's definitely not the > issue that modern Windows versions pretend that AMD does hyperthreading, > assuming that the CPUs in the systems are actually threads, and that the > core count is half the thread count). > > Klaus >> >> Many thanks, >> >> Laura _______________________________________________ vbox-dev mailing list [email protected] https://www.virtualbox.org/mailman/listinfo/vbox-dev
