Active RAM remains high when exit Parallels with XP Suspense

Discussion in 'Parallels Desktop for Mac' started by hln98, Feb 13, 2007.

  1. hln98

    hln98 Bit Poster

    Messages:
    18
    My Active RAM remains very high, leaving very little FREE memory back to OS X when I exit Parallels 3150 RC2 with a suspended XP Pro.

    If I Shut Down XP first, and then exit Parallels, my available RAM is full again.
     
  2. VTMac

    VTMac

    Messages:
    340
    When you suspend. are actually exiting Parallels or just suspending? If you are actually exiting, that sounds like a bug. If you are suspending, but leaving Parallels open, that is a "feature".
     
  3. hln98

    hln98 Bit Poster

    Messages:
    18
    Yes, suspense and then exit Parallels altogether, my Active remains extremely high. This is bug.
     
  4. dankow

    dankow

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    3
    I can confirm that this bug exists in build 3186 with XP. For me, the bug is intermittent and does not occur every time I suspend and quit Parallels.

    The host OS is 10.4.8 on a Core 2 Duo iMac with 2 GB of RAM.
     
  5. dankow

    dankow

    Messages:
    3
    The bug is still present in build 3188. I haven't been testing the beta builds, so I can't speak to them. Is there an official place to report bugs like this?
     
  6. unused_user_name

    unused_user_name

    Messages:
    495
    This is not a bug.

    There are lots of different kind of memory in OSX. "Free" means that the OS is not using it to cache anything. The "Free" memory should always be 0 if the system is going to have optomal performance, as it uses RAM as a cache to speed things up.

    What you want to look at is "Inactive" memory. That is memory that is being used as a cache but it not assigned to any program. MacOS will not dump memory immeadiately. Try an experament. Cold reboot your mac and start Parallels. Time (with a stopwatch) how long it takes to go from the click that start Parallels until your VM is ready to go. Now exit Parallels. Without doing anything else first, restart Parallels.

    It should be much faster the second time because MacOS does not clear out the RAM. It just marks it as being unused so that other programs can use it if needed. This is a rather old optimization as virtual memory advancements go. Windows Vista and MacOS uses it, and a bunch of research OSs from the 80's (and maybe solaris?) also uses this technique. Windows XP does not do this, which is why you perhaps are not used to it.
     
  7. neosublime

    neosublime

    Messages:
    62
    I am seeing this too. It shows my "Active" RAM as half used after I exit Parallels. I startup my Mac, check my RAM. Lauch Parallels only. Let it run for a bit, then suspend it. Wait a bit and recheck my activity monitor, and my "Active RAM is still high, but no paticular app is using alot of RAM. When I suspend it actually increases the "Active" RAM.

    MBP CD 2.0, 2GB, WinXP Pro SP2, 256MB
     
  8. neosublime

    neosublime

    Messages:
    62
    Temp fix, disable suspend, and switch to power off VM. Reclaims RAM.
     
  9. dankow

    dankow

    Messages:
    3
    This is indeed a bug. The original poster and I were referring to the active memory, not free or inactive memory. When an application quits, the memory that it uses should become inactive or free. In this case, Parallels sometimes does not allow the kernel to release the memory, and it stays active indefinitely. That memory will never be reclaimed by another process until the computer is restarted. Again, this behavior will only present itself when the VM is suspended. If you stop the VM and then quit Parallels, the memory that Parallels was using becomes inactive.
     

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