2GB Macbook, 600MB reserved, STILL swaps!

R

rowr

Bit poster
I've got a 2GB Macbook C2D and Parallels configured for 600MB reserved memory for a 500MB Windows XP vm. But............. I still get pageouts - what is going on?!?? I don't understand why any more memory gets consumed beyond the 600MB I gave to Parallels.

Activity Monitor shows 777MB wired, 392MB active, 845MB inactive and 1.98GB used.

Maybe i'm missing something - i'm a fairly new Mac user. But I still don't understand why the memory in my machine is getting soaked up (I'm not runnning any other applications) to the point of swapping. Help!
 
I also would like some comment on this issue.

I have a mac mini with the following specs:
Intel Core 2 Duo T7600 Merom 2.33GHz
2gb DDR667 Ram
Western Digital Raptor over SATA (chassis hack)
Windows XP SP2 on Parallels' March 07, 2007, 20gb Windows image

With 800mb of RAM allocated to windows, I get 30k-80k pageouts when starting parallels, and often I get about 2k pageouts/10 minutes when my computer just sits. (Might there be a memory leak?) This all happens from a cold boot. I have a pretty standard install of OS X running... I haven't even changed the default desktop picture! All I have running in the background is Firefox; when I start Parallels, Activity Monitor reports that I have >1gb RAM free. When I reduce Windows to use only 300-400 megs of RAM, I get fewer pageouts, but I still get pageouts.

I usually run Temperature Monitor (http://www.bresink.de/osx/TemperatureMonitor.html) in the background. Sometimes when Parallels starts, disk activity (pageouts) becomes so intense that Temperture Monitor crashes and reports that it 'lost contact with OS system components returning temperature.' I've also had other issues (installing USB drivers) where Parallels has caused my system to hang and/or halt.

But back to the memory problem, is this a Windows virtual memory issue? does Parallels hook Windows VM manager into that of Mac OS X?

What is the optimum amount of RAM to avoid any swap at all? E.g. if I had 4 gb of RAM and gave 1gb-2gb to Windows, would that squash this issue?
 
I start parallels from the dock

as a start up item togehter with my browser / firefox
mailer
nntp news groups / mozilla

and never experience these problems
I let the machine settle before I begin to use it

Hugh W
 
You might try decreasing the memory assigned to Parallels.

I have 2GB of real memory on my iMac, but I have only 256MB allocated to Parallels. Ther performance has been super (and much better than my old Dell).

What you want to avoid is for Parallels to have no swap activity, but OSX itself starts swapping like mad.
 
rowr said:
Activity Monitor shows 777MB wired, 392MB active, 845MB inactive and 1.98GB used.
Click to expand...

You do realize that 845MB inactive is that same thing as free in OSX. Both Linux and OSX are very different than windows. They agressively try to allocate all free memory to some task, because unallocated memory is wasted memory. You need to change your thinking as to how you interpret those numbers. Given you allocated 600 M to parallels, and OSX has it's own needs (and you didn't mention what else you might have running), I'd say your memory allocation looks just fine.
 
blah, i had VM caching on.. i swear it was off... that prolly makes a difference....

no pageouts yet, giving windows 245 megs of RAM.. firefox is eating 300...
 
Last edited:
pwais said:
blah, i had VM caching on.. i swear it was off... that prolly makes a difference....

no pageouts yet, giving windows 245 megs of RAM.. firefox is eating 300...
Click to expand...

Where are you turning VM caching on and off?
Also, how where are you seeing evidence of pageouts?

Thank you,

David
 
I turn VM caching on and off by going to the VM settings, I think its under general > advanced

see the user manual and search for "cache" or "caching":

http://download.parallels.com/GA/Parallels_Desktop_for_Mac_User_Guide.pdf

apparently VM caching makes parallels try to put the entire hard disk into RAM? WTF? that sounds crazy... maybe they just mean the VM's virtual memory into RAM, which is still nuts cuz I think windows allocates a system pagefile of a gig at startup right? turning off VM caching (choosing the 'optimize performance for mac os x' option) doesnt do this and I believe just allocates the simulated physical memory. the bottom line is that VM caching is only good for when you're running parallels all by itself basically, and I dunno why I turned that on but damn it runs a lot smoother with it off.


as for viewing pageout statistics, I use the activity monitor (spotlight "activity monitor")... I believe you have to click on the "disk" statistics tab somewhere to get to it...
 
VTMac said:
You do realize that 845MB inactive is that same thing as free in OSX. Both Linux and OSX are very different than windows. They agressively try to allocate all free memory to some task, because unallocated memory is wasted memory. You need to change your thinking as to how you interpret those numbers. Given you allocated 600 M to parallels, and OSX has it's own needs (and you didn't mention what else you might have running), I'd say your memory allocation looks just fine.
Click to expand...
I believe the wording that free memory is a "waste" is misleading and inaccurate but it bridges the gap of explaining to end users what is going on. "Deallocated" or "disk cache" probably would have been a better choice but they didn't ask me. I'm not going to be able to change that verbage so i'll leave it at that and move on.

This probably explains to some degree why the memory is getting consumed so quickly as disk cache, because Parallels is getting up to its 600MB allocation and the remaining memory pages are being used as cached reads from the disk image (I'd rather have XP in the VM cache its own reads, but...).

It's not a good thing to send pages to swap to make room for disk reads... Apple should tap into OpenSolaris for some advice how to manage swap, etc.
 
pwais said:
I turn VM caching on and off by going to the VM settings, I think its under general > advanced

see the user manual and search for "cache" or "caching":

http://download.parallels.com/GA/Parallels_Desktop_for_Mac_User_Guide.pdf

<snip>

as for viewing pageout statistics, I use the activity monitor (spotlight "activity monitor")... I believe you have to click on the "disk" statistics tab somewhere to get to it...
Click to expand...

I see that you can toggle virtual hard disk caching between VM and Mac OS X in
Configuration Editor>Options>Advanced. (No mention of this location in the user manual by the way.) Are saying that you get better performance of your VM when you toggle this for "better performance of: Mac OS X"?

Also, sorry to be so dense, but in Activity Monitor, under the Disk Activity or Disk Usage tabs, where do you see "pageouts?"

Thank you,

David
 
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pwais said:
apparently VM caching makes parallels try to put the entire hard disk into RAM? WTF? that sounds crazy... maybe they just mean the VM's virtual memory into RAM, which is still nuts cuz I think windows allocates a system pagefile of a gig at startup right? turning off VM caching (choosing the 'optimize performance for mac os x' option) doesnt do this and I believe just allocates the simulated physical memory. the bottom line is that VM caching is only good for when you're running parallels all by itself basically, and I dunno why I turned that on but damn it runs a lot smoother with it off.
Click to expand...
I know there's a lot of people who would disagree but I would never run a system pagefile in a Windows VM (I never use one at all, even on a standalone PC with 500MB memory). Just give it 500MB of RAM and no pagefile. Windows doesn't need a pagefile, it runs fine without it. System performance is going to be terrible once you start swapping so instead of punishing your hard disk, buy some more RAM.

(And for the naysayers, Windows does not intelligently pre-allocate swap to run executables like Solaris, etc. - the entire binary image is shoved into memory, so ditch the pagefile!)

Excellent tip by the way for disabling caching the VM disk image. I'm going to try that right now!

Thanks!
 
pwais said:
I turn VM caching on and off by going to the VM settings
Click to expand...
That's the setting I was looking for. Virtual hard disk cache policy of Mac OS X disables the cache of the virtual disk image and keeps the memory consumption at the level configured in the Configuration Editor. Setting the parameter to enhance the performance of the Virtual machine caches the virtual disk image but I cannot tell how much benefit there is to this. Windows maintains its own disk cache so perhaps this option isn't so useful when running Windows VMs?

I run a number of different applications at the same time so setting the parameter to "Mac OS X" is exactly what I was wanting. Unfortunately this is not described if you press the Help button but hopefully will be described in detail in future Parallels releases. That really, really should be highlighted in the online help.
 
rowr said:
That's the setting I was looking for. Virtual hard disk cache policy of Mac OS X disables the cache of the virtual disk image and keeps the memory consumption at the level configured in the Configuration Editor. Setting the parameter to enhance the performance of the Virtual machine caches the virtual disk image but I cannot tell how much benefit there is to this. Windows maintains its own disk cache so perhaps this option isn't so useful when running Windows VMs?

I run a number of different applications at the same time so setting the parameter to "Mac OS X" is exactly what I was wanting.
Click to expand...

With my setup at least, I seem to be having the opposite experience and would appreciate youir comments. Toggling the setting to enhance the performance of the VM makes the VM definitely faster.

MacBook Pro Core 2 Duo, 3 G RAM
Mac OS 10.4.9
Parallels 3188
XP Pro SP4, 768 MB of RAM dedicated to the VM
Active programs: QuickBooks 2007 for Windows; AVG (background)

Thank you,

David
 
the thing about a mac os is that it is highly automated and unless you are a developer just use the defaults

with parallels small is beautiful keep your data in shared folders not in the image

the seven years old macs needed memory management by users but that is automated now

Hugh W
 
I have followed the opinions here and some other threads, and I have made some pretty positive changes. I too had the constant hard-disk activity in the vm, and now I have none.

I am running Vista Ulitmate, Office 2007.
I changed the memory allocation to 680 MB RAM, and set the virtual caching policy to OS X.
Then I changed the max memory allocation to something like 790 MB in Parallel prefs.
Then I turned off the swap file entirely in Vista and rebooted.

So far, I am very pleased. Vista seems more snappy, and one of my biggest complaints, OS X sluggishness, has also subsided. Only time will tell if this keeps up, though...

Darrel
 
David5000 said:
With my setup at least, I seem to be having the opposite experience and would appreciate youir comments. Toggling the setting to enhance the performance of the VM makes the VM definitely faster.

MacBook Pro Core 2 Duo, 3 G RAM
Mac OS 10.4.9
Parallels 3188
XP Pro SP4, 768 MB of RAM dedicated to the VM
Active programs: QuickBooks 2007 for Windows; AVG (background)

Thank you,

David
Click to expand...

Caching the VM disk probably does make the VM faster - but my original intent was to reduce overall memory consumption. VM caching enables the entire block of physical memory to be up for grabs and that is not what I want. I chose to use the option to enhance the performance of the Mac OS because I wanted to preserve my Mac's memory for other applications. The wording of that option isn't the best - the two options should say "Allocate all memory to running Parallels" or "Use only the memory I have configured Parallels to use".
 
darreln said:
I am running Vista Ulitmate, Office 2007.
I changed the memory allocation to 680 MB RAM, and set the virtual caching policy to OS X.
Then I changed the max memory allocation to something like 790 MB in Parallel prefs.
Then I turned off the swap file entirely in Vista and rebooted.
Click to expand...
Curious... How much free memory does Vista show free after a fresh reboot and no applications running?

fwiw, my XP VM shows around 400MB free with 500MB configured for it after a reboot. After a while of using the XP VM the System Cache will grow into all available free memory (which reinforces my belief that caching the VM disk image is not a wise idea if you run other Mac apps like iMovie or Mac Word, etc.). As mentioned before I don't use a swap file in Windows.
 
rowr,
after a fresh Vista reboot, and no apps running, I show about 425 MB in use. Apple's Activity Monitor shows Parallels as using 420 MB real memory with a 2.16 Gig virtual memory pool.

So Vista shows 0 MB free, out of a total of 670 MB RAM.
 
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