Lots of pageouts with 24 GB RAM

[steve-p]

I was under the impression that the page out count also included moving pages to inactive RAM, in which case it would be normal for some to occur. Although looking at my MBP which has not been rebooted for a while, I guess that's wrong. I have 338MB in Inactive RAM but only 42.5MB in page outs, with 472 KB swap used.

 

[GGJstudios]

The screenshot above is my point. It begs the question: Why has Mac OS X not released the Inactive RAM yet? Why did it go straight to page outs?

The inactive RAM did not go into page outs. Inactive memory IS free memory that has been released by an app that previously used it. It is simply "marked" as inactive in case that same app is relaunched, in which case, that app will launch faster. If another app needs to use the inactive memory, it can, just like other free memory.

I was under the impression that the page out count also included moving pages to inactive RAM, in which case it would be normal for some to occur.

No, page outs are a completely separate thing from free or inactive memory. For memory to go from free to inactive, nothing is moved. Page outs only occur when you don't have sufficient free and inactive memory and RAM contents need to be written to disc to make room for new contents that are being paged in.

Mac OS X: Reading system memory usage in Activity Monitor

 

[stevemiller]

If we take that activity monitor ram pie chart out of the equation entirely, I think the crux of my and many other people's complaints with ram issues is that page outs DO occur on systems with plenty of memory, while doing tasks that should NOT be placing systems into a page-out scenario.

After effects is by and large the worst offender from my experience. It doesn't matter now small of a clip you place in a composition, if you scrub back and forth in time, it will somehow recache he the same frames over and over and over until all the ram in the system is consumed and the entire system chugs. No matter if it's 4gb, 8gb, 16gb. No matter how little ram you assign to after effects in preferences. And it's not a "oh the activity monitor shows page outs" situation, it's a "holy crap this 20mb image sequence has actually made my entire system lock up". It's persisted across multiple versions of OSX, multiple systems I've used, and multiple versions of after effects.

I mostly blame Adobe for having the worst coders in the universe, but I do also hold apple partially responsible for not having some OS level enforcement of applications that behave this way and can cause system wide instability.

 

[stevemiller]

I'm saying the screen shot is not conclusive at all. It doesn't demonstrate that page outs occurred at the same time there was inactive memory available. To do that, launch Activity Monitor while running a memory-intensive app and take successive time-stamped screen shots showing page outs beginning and continuing while inactive memory is available. I have never seen any user conclusively prove that page outs occur while inactive memory is available. There are several claims made, but no evidence to support it, beyond anecdotal claims.

sir, here is your proof. 3 screen shots taken in succession (check filenames for timestamps). i assure you that the gig and a half inactive memory did not suddenly disappear each time it paged out. the system continues to page out with inactive memory as i write this. i'm on a work system with 4gb right now, but i have had this happen on systems with 8gb and even 16gb of ram. it is very real, and the systems become unusably slow.