virtualbox lies about available processors on non-hyperthreaded processors
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Virtualbox |
New
|
Undecided
|
Unassigned |
Bug Description
I consider this bug extremely insidious as it can ruin the performance of linux while virtualbox is running. While setting up Oracle's virtualbox-5.1 on my MacPro 3,1 under Ubuntu 16.10, I was puzzled by the extremely bad system performance that I was seeing. Finally I realized that the Processor tab in virtualbox was showing the total available cores on my machine as 16 and the green bar showing the safe zone was extended to 8 cores. Thus any user on an older machine like mine (which has dual quad-core Harpertown processors) will be told to use twice the recommended number of cores. Once I reduced the cores used from 8 to 4, the system performance dramatically improved. This should be trivial to fix as virtualbox should just check /proc/cpuinfo for the correct values and stop assuming hyperthreading is universally available. I have filed this upstream with Oracle as https:/
Screen shot of Processor panel in virtualbox 5.1.10 under Ubuntu 16.10 on MacPro 3,1 with dual quad-core Harpertown processors that lack hyperthreading support.