Rosetta causing significant Memory leaks (active and inactive mem)

Question

Rosetta causing significant Memory leaks (active and inactive mem)

(system - iMac Duo 2.0Ghz 1.5GB RAM)
I've noticed that a few programs I run in Rosetta really munch up the system's RAM quickly, especially when working with large files. Example applications include MS Word, Scantango scanning software, Limewire, etc. First observation is that every application cumulatively bulids is Real memory usage as it runs and working with large or various files. Unlike native app's or when running programs under PPC platform, the memory is not returned to the "Free" state when closing documents with the app's but instead maintains an allocation in "Active". Second observation is that when I do close the Rosetta-running programs to free up the RAM (not unusual for a few programs to quickly get to 1GB+ of Real memory usage), the memory that was used stays in "Inactive" rather than being truly freed up. Not until a full restart is the Inactive memory associated with these applications cleared.

So, first issue of leakage of Active memory - I assume this is just a reality in running with Rosetta and not much to do here?

Second issue with Inactive memory "leakage" - is this an issue I should be considered. I don't have a sense for the implications of Inactive versus Free memory allocations.

Thanks for any thoughts!

iMac 2GHz Core Duo, iBook 12 1.33, Mac OS X (10.4.4)

Posted on Feb 17, 2006 6:23 PM

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Answer 1

tthiel1

Level 2

184 points

Feb 17, 2006 6:59 PM in response to BlueLightSpectrum

I went from 1.5 to 2 GB ram because I noticed I consistently had only 20 or 30 MB left over. Now Unix is good at using available memory unlike Windows but it didn't make sense that after I closed apps I still had so little memory regained. I now have 2 GB ram and still have the same issue. This did not use to happen with my G5 desktop or iMac. So I think your on to something. I now only have Safari, Mail, and the Unison Newsreader running all three of which are Universal and practically none of the memory used by PPC apps has been returned to the OS.

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Answer 2

Spire

Level 4

1,300 points

Feb 17, 2006 8:33 PM in response to BlueLightSpectrum

As I understand it Rosetta caches the translated instructions into Memory, and as Rosetta runs in the same memory space as the application this is where it would end up putting it so the memory used by the APP would increase as it was run and more cached code build up in its memory space.
I read somewhere that 1.5 to 3 times the memory space is used by Rosetta apps compared to Intel native.

OSX keeps memory around and merely converts it to 'Inactive' when its not in use anymore, if the memory space is needed then it frees up the inactive memory. If not it keeps it around for possible reuse later rather then having to reload it into RAM again.

Think or 'Free Memory' as wasted space, its sitting there not doing anything. Inactive is not doing anything at the moment but could have its contents used again if needed but is available space for use if needed, and 'Active' is in use.

This is my Understanding anyways but I'm far from knowledgeable in such matters.

--Spire

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Answer 3

tthiel1

Level 2

184 points

Feb 17, 2006 10:57 PM in response to Spire

Yup I know how inactive memory works but even so releasing no memory for hours when only one app is running is not normal. If it makes a difference I am a very experienced Systems Architect with many years of Unix experience including an awful of of BSD. Inactive memory is information that is no longer being used but is cached anyway. I think this is rosetta caching inactive memory when I have about 1 GB of inactive memory.

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Answer 4

Feb 18, 2006 4:20 AM in response to tthiel1

I was confused too initially. But there is nothing wrong with the virtual memory manager. It is just how you interpret it. Inactive memory is the memory that has been used and that is no longer used. Which means that is reclaimed when necessary. "When necessary" is the key. The data is not immediately reclaimed just to optimize in scenarios when the same is relaunched again.
So for all practical purposes you should add free memory+inactive memory to estimate hoe much memory u have before some "thrashing occurs. hope this helps.

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Answer 5

Feb 18, 2006 5:55 AM in response to Scarface70a

what's funny is the OSX doesn't seem to do this in the same magnitude on PPC, and appears to me to be quite different under OSXintel

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Answer 6

Feb 19, 2006 9:52 AM in response to BlueLightSpectrum

Interestingly, I'm noticing a fair amount of allocated Active memory even after I've quit all programs (leaving on the system app's). This never happened to me on PPC, as OSX always cleared it very quickly returning it to Free memory. Here's a screenshot of my Activity Monitor:

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Answer 7

Feb 19, 2006 10:45 AM in response to BlueLightSpectrum

I'd click on 'All processes' and see where the extra active memory is being used, since it's not really showing up in your 'my processes' display.

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Answer 8

May 5, 2006 8:12 AM in response to BlueLightSpectrum

I have noticed the same behavior. I use excel, word, skype, and microsoft messenger as my four main rosetta apps. I'm constantly going into excel and word and quitting them. When quitting them, memory is released, but not all the memory. What I've noticed is that the rosetta process (translated) ends up showing < 1MB in use, but the virtual memory grows over time. I've seen it go from 26MB of virt memory to well over 1GB just from opening and closing these programs over several days.

My inactive memory pool grows to over 1GB. After quitting all my rosetta apps, if I kill the translated process, I easily free up the 700MB of inactive memory to free memory. I would definitely say there is a rosetta leak.<br>
PowerBook G4 1.67 Mac OS X (10.4.4)

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Answer 9

May 5, 2006 9:20 AM in response to BlueLightSpectrum

Bluelight,

hey there, I find it interesting to see what other users are going through on there intels,I have the same amount of RAM 1.5 use much of the same apps, word,excel and the like,and as I monitor my system memory and almost always have 1gb or better left open,meaning my system usage is usually .5gb at most,though I always quit each process completely including Safari which I clear its cache everyday,I must say you are eating up RAM pretty good,hope you figure it out,
Jappleseed

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