id summary reporter owner description type status component version resolution keywords cc guest host 8987 Slow boot / high CPU load / snapshot delete stalls on 12 core Family 10h Opteron Ubuntu 10.04 Jens Wilke "I have some ""multiple"" strange behaviours on a new host system. Parameters: Host: Ubuntu 10.04 aka Lucid 64 Bit, Kernel 2.6.32-31 Guest: Ubuntu 10.04 aka Lucid 32 Bit, Kernel 2.6.32-31 Virtualbox Version 4.0.8 AMD Opteron(tm) Processor 6174 I also did test with 11.04 and Kernel 2.6.38-8, and experimented with various guest options (ioapic, acpi, etc.). Overall, the behaviour keeps identicall. Observations: 1. Slow output on the UART during boot. 2. The boot is slow. The process takes 55 seconds when 12 cores are enabled and 10 seconds when only 1 core is enabled. 3. When switching to multiple CPUs in the guest the UART output is corrupted during the initial boot phase. 4. When deleting a snapshot it stalls at 90% and the following processes run at the given CPU %, 63% VBoxSVC, 62% VBoxHeadless, 29% VBoxXPCOMIPCD. I wait for 20 minutes, no change. Then I aborted via rebooting the system. The attached logs concentrate on the boot of in 10.04 with identical VM parameters, I did the following comparisons: 12core: All cores are enabled 1core: disabled all but one cpu with: for I in 1 2 3 4 5 6 7 8 9 10 11; do echo 0 > /sys/devices/system/cpu/cpu$I/online; done downcore: Enabled BIOS Downcore setting to 1 core, which gives me 2 cores in reality. 1core and downcore have fine behaviour. So when the host system is booted with only 2 cores enabled, everything is fine! " defect closed VMM/HWACCM VirtualBox 4.0.8 fixed slow boot, high cpu usage, Opteron Family 10h, Ubuntu 10.04, Ubuntu 11.04 Linux Linux