Hi guys,
I have made a question on the askUbuntu forums and it seems this is definitely at least more related to VMware Workstation 9 as opposed to the OS (http://askubuntu.com/questions/221554/ubuntu-12-10-and-vmware-workstation-9-ram-caching-causes-severe-performance-dro)
Plain and simple of it:
- Ubuntu allocates memory as: user, shared, buffers, disk cache. Then there is swap space on top of this. 'Swappiness' describes the kernels 'hastiness' in swapping thing out to swap space (memory allocated on the disk) - 0 means only swap when RAM is full. The disk cache is used by the OS to make accessing files quicker and more efficient. AS APPLICATIONS NEED MORE MEMORY, this memory is RELEASED by the kernel to be given to the requesting application
- My Windows 7 VM is allocated 1.5GB of RAM and the task correctly takes up ~1.8GB memory as displayed in system monitors, BUT my overall memory monitor (confirmed amongst multiple different utilities), is showing that it seems this 1.8GB is being made disk cache type memory for some bizarre reason
- My performance is absolutely terrible (literally 5 minutes+ for some basic operations like changing windows - happens frame by frame) as my system memory usage is 3GB+ / 4GB
Without any way of proving this, it seems quite logical that this is what is happening:
- OS gives the VM the memory, for some odd reason it is either declared or interpreted as Disk Cache
- When memory limits are reached (Ubuntu consistently uses as much memory as possible - i.e. full use, with the Disk Cache reduced to accomodate memory needed for applications), the OS / kernel is trying to release the disk cache to give the task at hand memory, but cannot because it is in fact application memory.
- Because the kernel is designed (with a standard low swappiness value) to use disk cache THEN move into swap memory, it is not even trying to use swap memory, it is just sitting there trying to release the disk cache memory occupied by the faulty vmware process and failing and then retrying, and over and over while my system goes into complete lockdown.
Any help / confirmation this is a bug / suggestions about what could be causing this from within my system (seems wrong - VMware Workstation 9 is the ONLY program I have had any memory allocation type issues with) would be much appreciated!
Thanks guys.
Note 1: "Raise swappiness to ridiciulously high" is not an option as hard drive memory, although 'usable', is still a lot slower than normal memory
Note 2: I have come from Virtualbox and have not had these problems at all. Workstation is much more polished product which I would love to continue using but obviously won't be able to if even basic use renders the rest of my system unusable