1 2 3 Previous Next 36 Replies Latest reply on Mar 25, 2008 12:33 PM by magic-man

    2 XP Guests, Turn off Paging?

    BassKozz Enthusiast

       

      If I am running 2 Windows XP Guest VM's at the same time, would it be benificial to turn off paging, So that way both VM's aren't accessing the HD as a Paging file at the same time (slow down) ?

       

       

      p.s. Each VM has 1.5gb RAM alloted to it.

       

      ---

      VMware Workstation v6.0.2 build-59824

      Host OS: Ubuntu 7.10 64-bit

       

       

        • 1. Re: 2 XP Guests, Turn off Paging?
          continuum Guru
          User ModeratorsvExpert

          Turn of pagefile in the guest is a bad idea -  better assign less RAM and make sure your host is configured somehow like this

           

          sched.mem.pshare.enable = "FALSE"

          prefvmx.useRecommendedLockedMemSize = "TRUE"

          prefvmx.minVmMemPct = "100"

          priority.grabbed = "normal"

          priority.ungrabbed = "normal"

          mainMem.partialLazySave = "FALSE"

          mainMem.partialLazyRestore = "FALSE"

          mainMem.useNamedFile = "FALSE"

           

          As you use Linux you can't prevent swapping completely

           

           

          • 2. Re: 2 XP Guests, Turn off Paging?
            BassKozz Enthusiast

             

            Thanks continuum,

             

            continuum wrote:

            Turn of pagefile in the guest is a bad idea -  better assign less RAM and make sure your host is configured somehow like this

             

            sched.mem.pshare.enable = "FALSE"

            prefvmx.useRecommendedLockedMemSize = "TRUE"

            prefvmx.minVmMemPct = "100"

            priority.grabbed = "normal"

            priority.ungrabbed = "normal"

            mainMem.partialLazySave = "FALSE"

            mainMem.partialLazyRestore = "FALSE"

            mainMem.useNamedFile = "FALSE"

             

            As you use Linux you can't prevent swapping completely

             

             

             

            But how can I check if my Guest VM's are set w/ those settings (in the VMware Workstation GUI)?

            p.s. I relize I can't prevent swapping in linux, but I assumed it would be good to turn off paging on the XP Guests because they will both be fighting for the same HD access for their paging files.

             

             

            • 3. Re: 2 XP Guests, Turn off Paging?
              continuum Guru
              User ModeratorsvExpert

              A XP with turned off pagefile has to be very very careful with assigning ram to any processes - you will not like the results.

               

              The settings i mentioned should be entered into the global config-file - which is  /etc/vmware/config afaik

               

               

               

               

              1 person found this helpful
              • 4. Re: 2 XP Guests, Turn off Paging?
                BassKozz Enthusiast

                 

                Thanks again continuum,

                 

                 

                You were correct about /etc/vmware/config being the file I need to change, but before I dump (copy+paste) those lines into the config file, will this have a negative effect on other non-M$ VM's?  For example if I add these lines to the config file and i then decide to run a linux based OS as a Guest VM will these config settings mess that up? or do these settings only pertain to MS Windows Guest OS's/VM's ?

                 

                 

                • 5. Re: 2 XP Guests, Turn off Paging?
                  continuum Guru
                  vExpertUser Moderators

                   

                  Hi

                   

                   

                  config(ini) settings are host-wide - they affect every VM.

                  I always use the one I posted  - and I run Win, Linux and BSD as VMs.

                   

                  The settings may prevent to run 400 VMs at the same time - but they will help to run a a couple of VMs as fast as possible.

                   

                  Any way - testing doesn't hurt - make a backup of the file to be able to revert - you will not need it though - promised

                   

                   

                  1 person found this helpful
                  • 6. Re: 2 XP Guests, Turn off Paging?
                    BassKozz Enthusiast

                    Pasted the lines to the config file, so far so good... Thanks continuum .

                     

                    Can you point me in the direction of info on these lines and what each one does?

                    Is there a reference guide for these settings?

                     

                     

                    p.s. I don't expect you to explain each line for me, I can do my own research, but can you point me in the direction where I should start digging?

                    Thanks,

                    -BassKozz

                    • 7. Re: 2 XP Guests, Turn off Paging?
                      continuum Guru
                      vExpertUser Moderators

                      VMware says you  should not edit config-files - you should use the gui instead.

                      Thats why there is no real good documentation for these entries in config.ini

                       

                      Start reading on my site instead

                      http://sanbarrow.com/vmx/vmx-config-ini.html

                       

                      If anything needs more explanation - ask - I'll try to explain then

                       

                       

                       

                       

                       

                      • 8. Re: 2 XP Guests, Turn off Paging?
                        BassKozz Enthusiast

                         

                        Thanks again for all the help,

                         

                         

                        sorta Off-Topic:

                         

                         

                        While I have your expert attention continuum, I have another question for you;

                        I have a Quad Core (Q6600) Rig, and I am running 2 instances of WinXP as Guest VM's (one for work & one for play ), both of these VM's are setup to use 2 processors (using the GUI configuration)...

                         

                         

                        My question is, is this ok because I am using all 4 cores (2 for each guest VM), and not leaving one for the Host (Ubuntu) ?

                        Or should I run one VM with 2 cores, and the other with 1 core, leaving the fourth core available for the host?

                         

                         

                        Thanks again for all the help, it is truly appreciated.

                        -BassKozz

                         

                         

                        • 9. Re: 2 XP Guests, Turn off Paging?
                          continuum Guru
                          User ModeratorsvExpert

                          Your setup sounds ok - it is still possible that single-cpu VMs would actually perform better - it depends on the apps you are using

                           

                           

                           

                           

                           

                          • 10. Re: 2 XP Guests, Turn off Paging?
                            BassKozz Enthusiast
                            continuum wrote:

                            it is still possible that single-cpu VMs would actually perform better - it depends on the apps you are using

                             

                             

                             

                             

                            I keep hearing that, but wouldn't running more then one application at the same time kick in both cores (therefore better performance vs. single core)?

                             

                             

                            For Example:

                            Let's say I am just browsing the web (Firefox) and typing a word document (MS Office) at the same time, while both of these applications aren't "built" for multi-threading (per-se), but because of the fact that I am running 2 separate applications, shouldn't they utilize both cores? Or for example if I were to run 2 instances of the same application (say Firefox twice), wouldn't one see better performance from 2 cores vs 1 because of the mere fact that you are running multiple instances/processes?

                             

                             

                             

                             

                             

                            • 11. Re: 2 XP Guests, Turn off Paging?
                              Peter_vm Guru

                              Keep in mind that host OS process scheduler must find idling two logical host CPUs at the same time to execute some work requested by vSMP guest.

                              That's harder (longer wait time) from host's perspective; and guest performance might suffer as a result of that.

                              This is the reason why best practise recommends to have plenty (4 or more) host logical CPUs for vSMP guests.

                              • 12. Re: 2 XP Guests, Turn off Paging?
                                continuum Guru
                                vExpertUser Moderators

                                 

                                Basskozz - VMs simply don't scale like real metal.

                                A real metal XP should get faster and faster when adding RAM for example until you reach the limit of what XP can handle nicely (2Gb)

                                 

                                 

                                A XP-VM reacts differently - it gets faster until some value between 512 and 1024 MB is reached and if you add more RAM it slows down again.

                                 

                                A real metal XP gets faster if you use large empty disks - like the ones you can buy these days. A XP running from a 160Gb disk usually is faster than one from a 30 Gb disk.

                                 

                                Again with an XP-VM this is different - best results may be acchieved when you run it from a 8Gb - maybe 12 Gb disk - enlarging the disk makes the VM slower.

                                 

                                Same with virtual CPUs:

                                in a real XP two CPUs are running more or less in sync - just because they are build to run at the same timing.

                                In a XP-VM VMware must use additional CPU-cycles to bring cpu1 and cpu2 in sync - this is not required if you run only one CPU.

                                So it often is an effective slowdown if you add a second CPU.

                                 

                                There is no easy rule-of-thumb to calculate this effects - best way is : find your personal values as they depend on your box and the apps you want to run.

                                generally speaking ... less is more

                                 

                                 

                                • 13. Re: 2 XP Guests, Turn off Paging?
                                  BassKozz Enthusiast
                                  continuum wrote:

                                  Basskozz - VMs simply don't scale like real metal.

                                  A real metal XP should get faster and faster when adding RAM for example until you reach the limit of what XP can handle nicely (2Gb)

                                   

                                  A XP-VM reacts differently - it gets faster until some value between 512 and 1024 MB is reached and if you add more RAM it slows down again.

                                   

                                  A real metal XP gets faster if you use large empty disks - like the ones you can buy these days. A XP running from a 160Gb disk usually is faster than one from a 30 Gb disk.

                                   

                                  Again with an XP-VM this is different - best results may be acchieved when you run it from a 8Gb - maybe 12 Gb disk - enlarging the disk makes the VM slower.

                                   

                                  Same with virtual CPUs:

                                  in a real XP two CPUs are running more or less in sync - just because they are build to run at the same timing.

                                  In a XP-VM VMware must use additional CPU-cycles to bring cpu1 and cpu2 in sync - this is not required if you run only one CPU.

                                  So it often is an effective slowdown if you add a second CPU.

                                   

                                  There is no easy rule-of-thumb to calculate this effects - best way is : find your personal values as they depend on your box and the apps you want to run.

                                  generally speaking ... less is more

                                   

                                   

                                   

                                   

                                  WOW , This is completely opposite of what I would expect ?:| ... I am stuck in the mindset of; "The more the merrier" 

                                  More RAM = Better Perfromance / You can run more applications at once because each application can eat away at the ram instead of having to share

                                  More Cores = Better Performance / You can run more applications at once because each application can use it's own core instead of having to share cores

                                   

                                  My Host machine is Ubuntu 7.10 64-bit w/ 4gb or RAM Quad Core (Q6600)...

                                  I am currently running the two VM's with the following settings:

                                  WORK = WinXP 32bit /  1.5gb of RAM / 2 cores

                                  PLAY = WinXP 32bit /  1.5gb of RAM /  2 cores

                                   

                                   

                                   

                                  But based upon what your saying I should be running more like:

                                  WORK = WinXP 32bit /  1gb of RAM / 1 core

                                  PLAY = WinXP 32bit /  1gb of RAM / 1 core

                                  ???

                                   

                                   

                                  I can't wrap my head around why less ram and less cores = better performance,  can you point me in the direction of some research on this, preferably w/ benchmarks?

                                  It's not that I don't trust you, it's that it just doesn't make logical sense ?:|

                                  Sorry to have to question the expert hear but my newb/pea-brain doesn't get it

                                  • 14. Re: 2 XP Guests, Turn off Paging?
                                    continuum Guru
                                    vExpertUser Moderators

                                     

                                    > ... research on this, preferably w/ benchmarks?

                                     

                                    Sorry - don't know any good links - its just based on my experience.

                                     

                                    Got a notebook with 4Gb RAM and dual core CPU: a guest 2k3 with 2 Gb virtual RAM and 2 CPUs performs poor - same guest with 1Gb RAM - single CPU rocks.

                                     

                                    Try it - I am sure your second version with

                                    WORK = WinXP 32bit / 1gb of RAM / 1 core

                                    PLAY = WinXP 32bit / 1gb of RAM / 1 core

                                     

                                     

                                    will outrun the first on most apps - maybe not if you test with SQL database stuff or things like that

                                     

                                     

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