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User profile for user: Jim Mauro
Jim Mauro Author
User level: Level 2
294 points

Slow MBP with paging messages and a lot of memory

My MBP gets sluggish - I can hear the disk seeking when the beachball spins.


Below find a cut from my kernel.log file. The system is running 10.7.3 and has 8GB

of RAM. According to the activity monitor, over 4GB is free.


Basically, my MBP has turned into a Windows PC. I need to reboot it every couple

weeks to get it snappy again.


I'm digging into this further, but thought I'd post it and see if I get lucky.

I have no idea why the system needs to page with so much free

memory. LO_WAT_ALTERT is likely a low water mark, it seems

on swap space, but with a ton of free disk (100GB free disk) and

free memory (4GB free RAM) I can not imagine why a low water

mark is being hit.


Thanks

Jim


Apr 8 21:40:17 James-Mauros-MacBook-Pro kernel[0]: IOSurface: buffer allocation size is zero

Apr 8 21:40:25 James-Mauros-MacBook-Pro kernel[0]: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT

Apr 8 21:40:26 James-Mauros-MacBook-Pro kernel[0]: IOSurface: buffer allocation size is zero

Apr 8 21:40:32 James-Mauros-MacBook-Pro kernel[0]: macx_swapoff SUCCESS

Apr 8 21:40:49 James-Mauros-MacBook-Pro kernel[0]: IOSurface: buffer allocation size is zero

Apr 8 21:40:57 James-Mauros-MacBook-Pro kernel[0]: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT

Apr 8 21:41:02 James-Mauros-MacBook-Pro kernel[0]: macx_swapoff SUCCESS

Apr 8 21:41:03 James-Mauros-MacBook-Pro kernel[0]: IOSurface: buffer allocation size is zero

Apr 8 21:41:30 James-Mauros-MacBook-Pro kernel[0]: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT

Apr 8 21:41:42 James-Mauros-MacBook-Pro kernel[0]: macx_swapoff SUCCESS

Apr 8 21:42:03 James-Mauros-MacBook-Pro kernel[0]: (default pager): [KERNEL]: default_pager_backing_store_monitor - send LO_WAT_ALERT

Apr 8 21:42:12 James-Mauros-MacBook-Pro kernel[0]: macx_swapoff SUCCESS

MacBook Pro 2.66Ghz Core i7 15.4", Mac OS X (10.6.4), 4GB RAM, 500GB HD, 1TB external LaCie

Posted on Apr 8, 2012 6:46 PM

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6 replies
User profile for user: Linc Davis
Linc Davis
User level: Level 10
209,547 points

Apr 8, 2012 7:07 PM in response to Jim Mauro

Launch the Activity Monitor application in any of the following ways:


☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)


☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.


☞ If you’re running Mac OS X 10.7 or later, open LaunchPad. Click Utilities, then Activity Monitor in the page that opens.


Select the System Memory tab. What values are shown in the bottom part of the window for Page outs and Swap used?

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User profile for user: Jim Mauro
Jim Mauro Author
User level: Level 2
294 points

Apr 8, 2012 7:28 PM in response to Linc Davis

Page outs 1.31GB (0 bytes/sec)

Swap used 1004.4 MB


So 1GB of swap used, 1.3GB of page outs.


Please keep in mind this is after-the-fact. The system goes sluggish

and this stuff happens for a while, then it settles down.


The largest memory consumer is always Safari, sometimes over 700MB

of physical memory. But again, I have near 4GB free.


Thanks

Jim

Reply
User profile for user: Linc Davis
Linc Davis
User level: Level 10
209,547 points

Apr 8, 2012 7:34 PM in response to Jim Mauro

Your problem is excessive swapping of data between physical memory and virtual memory.


That can happen for two reasons:


(1) You have a long-running process with a memory leak (i.e., a bug), or

(2) You don't have enough memory installed for your usage pattern.


Tracking down a memory leak can be difficult, and it may come down to a process of elimination. In Activity Monitor, select All Processes from the menu in the toolbar, if not already selected. Click the heading of the Real Mem column in the process table once or twice to sort the table with the highest value at the top. Repeat with the Virtual Mem column. If one process (not including "kernel_task") is using much more memory than all the others, that could be an indication of a leak. A better indication would be a process that continually grabs more and more memory over time without ever releasing it.


If you don't have an obvious memory leak, your options are to install more memory (if possible) or to run fewer programs simultaneously.

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User profile for user: Jim Mauro
Jim Mauro Author
User level: Level 2
294 points

Apr 8, 2012 7:43 PM in response to Linc Davis

I thank you for your time and attention, but I respectfully disagree.

This MBP has 8GB of RAM installed, with 4GB free, even when things

get sluggish.


Monitoring memory usage with the Activity Monitor shows the only process

consuming (what appears to be) an inordinate amount of RAM is Safari.

Having quit and restarted Safari, it's sitting at about 400MB right now,

but I've observed it as high as 700MB. That's a lot of RAM for a WEB

browser, but again there's still 4GB free.


Thanks for your time. Personally, I think it's a bug in the kernel.

With all the free memory and free disk space I have, it should

not be getting bogged down in paging. But that's just my opinion.


Thanks

Jim

Reply

Slow MBP with paging messages and a lot of memory

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