DChabot

Q: kernel_task consumes a lot of RAM in early 2011 MBP, sometimes Finder too

Hi,

My old MBP3,1 (late 2007, 2.4 GHz Core 2 Duo) worked quite well with 4 GB of RAM, even after weeks without restarting. In fact, I used all available RAM only on some larger analyses using R, which loads the entire dataset in memory. To be able to run these few analyses faster on my new machine (early 2011 MBP), I bought the 8 GB RAM option.

In Activity Monitor, I noticed something strange. Whereas my old MBP shows kernel_taks as using between 100 and 200 MB of RAM, the new MBP uses about 550 MB just after the machine started up and often shows over 600 after a few hours or days of use. A one year old iMac, again Core 2 Duo with 4 GB of RAM, gives a kernel_task memory usage below 200 MB after weeks of use.

I've not been able to find what kernel_task does. Is this amount (around 600 MB, but it has gone up to 800) normal? Is it managiing the additional number of cores that requires this behind the scenes amount of RAM?

Anyway, I now quite often have more than 4 GB of RAM in use even when I have only a few applications running (not even including R!), which surprises me.

Also today, after moving a lot of files back and forth between an external drive and the new MBP, after emptying the garbage can that contained a hefty number of files and doing a first Time Machine backup, the Finder ended up using 2,4 GB of RAM according to Activity Monitor. I have never seen anything like this (although I admit not having Activity Monitor on all the time). Even after the backup was finished and the external drive disconnected (in fact the machine was left idling for a few hours) cpu usage was down to nearly zero, the Finder kept its 2.4 GB of RAM. I restarted and the new RAM usage for the Finder was 26 MB. I have a screen shot showing the 2.4 GB, but I could not find a way to attach it to this message. I can send it by email on request. I don't think this Finder behavior was normal.

Somewhat worried,

Denis

MacBook Pro 2.2 GHz i7, 8 GB RAM, Mac OS X (10.6.6)

Posted on Mar 16, 2011 12:04 AM

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Q: kernel_task consumes a lot of RAM in early 2011 MBP, sometimes Finder too

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  • by wyager,

    wyager wyager Sep 22, 2011 7:45 PM in response to John P.
    Level 1 (0 points)
    Sep 22, 2011 7:45 PM in response to John P.

    Subtract the RAM used by Kernel_task from your wired memory. Is it equal to or greater than the RAM allocated to the integrated graphics? Mine always is. I think the graphics RAM is part of wired memory, but NOT part of K_t.

     

     

    ETA:

    looks like you added to your post.

    When I turn off integrated graphics, K_t's RAM usage does NOT go down. That article is incorrect, at least for this situation.

  • by ylluminate,

    ylluminate ylluminate Oct 17, 2011 11:55 AM in response to wyager
    Level 1 (10 points)
    Oct 17, 2011 11:55 AM in response to wyager

    I believe that this is realted to the parent of this thread: https://discussions.apple.com/message/16420653#16420653

     

    I don't think this is specific to that particular MBP model, but rather an OS issue and is still being seen in newer OS releases.

  • by pghguy,

    pghguy pghguy Oct 19, 2011 11:15 AM in response to ylluminate
    Level 1 (0 points)
    Oct 19, 2011 11:15 AM in response to ylluminate

    I have a Mac Server 10.6.8 (2 x 2.4 GHz quad-core xenon) with 32 GB RAM and my kernel_task (64-bit) is using 2.91 GB of real memory (even after a fresh reboot). Is this more evidence that as you add more RAM, kernel_task is going to take up more memory space? BTW, the private memory for this process is 40 MB.

  • by sfinktah,

    sfinktah sfinktah Oct 28, 2011 4:33 AM in response to DChabot
    Level 1 (0 points)
    Oct 28, 2011 4:33 AM in response to DChabot

    Are you guys taking into account the Virtual Memory that is being used as well?  Because that really adds up, and then you get high "page outs" (anything > 100mb is high) and it's really going to slow your machine down.

     

    Fortunately my kernel_task (or unfortunately?) mine is pretty much all active in memory... which means, whatever it's doing, it thinks it's important.

     

    I'm running a mid-2010 MBP with 8gb, 10.6.8.  fyi.

     

    activity.png

  • by drekka,

    drekka drekka Nov 10, 2011 10:05 PM in response to DChabot
    Level 1 (10 points)
    Nov 10, 2011 10:05 PM in response to DChabot

    Just for everyone's info ...

     

    I just received a 17" MBP with a 2.5Hz i7 CPU this week. Last night I upgraded it by adding a 16G OWC memory kit.

     

    As I type I have 3 users logged in, multiple copies of XCode running, Simulator and Aperture running, mutltiple Tower, Email, Safari and other software all running. Kernel_task is taken 1.08G of RAM and ticking over at about 1.5% CPU, probably due to iStat menus and Activity Monitor. In all, Activity Monitor reports 8.67G of RAM being used.

     

    And it's running beautifully. I was a little concerned at the memory usage of the kernel which is how I got to this thread, but as the machine is still screamingly fast - not that concerned.

     

    So it does appear that the kernel will scale in relation to how much raw RAM you have, based on my results vs others mentioned here.

  • by lofujai,

    lofujai lofujai Nov 15, 2011 8:48 PM in response to DChabot
    Level 1 (0 points)
    Nov 15, 2011 8:48 PM in response to DChabot

    I have an iMac 27" 3.4GHz i7 and 13" MBA 2.8GHz i7.  They are both running 10.7.2.  My MBA has 4GB and because I'm running out of memory on my iMac, I just upgraded it from 4GB to 12GB.  Now myu iMac is running much much faster.  But I notice that the kernel_task uses up much more Read Mem on my iMac.  It is at 896.2MB while on the MBA is only 347.4MB.  Looking at other process here is what I see

     

                             iMac               MBA

    Firebox              160.9MB          77.4MB

    Chrome              83.3MB           44.9MB

    MS Word            96.8MB          52.8MB

    Excel                 79.7MB          39.6MB

  • by rodrigocbv,

    rodrigocbv rodrigocbv Dec 12, 2011 12:38 PM in response to DChabot
    Level 1 (0 points)
    Dec 12, 2011 12:38 PM in response to DChabot

    I have exactly the same problem. I got a new MBP 2.2Ghz, i7 with 4Gb of RAM. Kernel is around 600Mb. The computer freezes constantly due to lack of memory. My old laptop, a MacBook Pro 2.66Ghz, Intel Core Duo with the same 4Gb of RAM, used to be way faster and this kind of problem never happened. I wish I have never done this upgrade!

  • by CT,

    CT CT Dec 12, 2011 12:40 PM in response to rodrigocbv
    Level 6 (17,883 points)
    Notebooks
    Dec 12, 2011 12:40 PM in response to rodrigocbv

    Ok, sounds good! Thanks for sharing!

  • by drekka,

    drekka drekka Dec 12, 2011 2:20 PM in response to rodrigocbv
    Level 1 (10 points)
    Dec 12, 2011 2:20 PM in response to rodrigocbv

    @rodrigocbv - Now that does sound odd. I did a similar thing, I upgraded from a early 2008 pre-unibody Macbook Pro 17 with a core 2 duo at 2.66Ghz and 4G RAM, to a 2011 core i7 @2.5GHz with 4G RAM and then swapped in 16G RAM a week later.

     

    The new machine was noticibly quicker than the old, even with the same memory. Given that memory limits how much you can run at one time without swapping and therefore only effects speed when you reach capcacity, that newer machine should be much quicker. With the way modern OS's work, limited memory will slow a machine by swapping to the hard drive a lot, but not freeze it.

     

    If your MBP is freezing I would suggest that there is a different problem. Freezes are an indicator of a more serious software or hardware problem. For example, in my pre-Apple days I built a new machine which would randomly freeze for no reason. After a couple of days I ran an extensive range of RAM checking sotware which found a bad RAM chip. I replaced the RAM and the machine ran beautifully afer that. I've seen similar things from faulty video cards or miss-matched drivers and hardware.

     

    I would suggest running some extensive diagnostics if you are comfortable dealing with hardware at that level, or take the machine into an Apple store for testing.

     

    Your new MBP should not be freezing up.

  • by rodrigocbv,

    rodrigocbv rodrigocbv Dec 12, 2011 4:18 PM in response to drekka
    Level 1 (0 points)
    Dec 12, 2011 4:18 PM in response to drekka

    @drekka  - Thanks for the reply. The machine is indeed faster when there's enough free memory. However, I used to run up to 4 different applications with my old mac without a ANY problem. With the new one, I run the same applications (Skype, Excel, iTunes and Chrome) at the same time but there's not enough memory. The system becomes noticeably slow.

    I'll probably increase the memory to 8Gb soon but I find it strange that the performance is worse with a supposidely better machine.

  • by Cyberpundit,

    Cyberpundit Cyberpundit Dec 27, 2011 1:10 PM in response to rodrigocbv
    Level 1 (5 points)
    Dec 27, 2011 1:10 PM in response to rodrigocbv

    Did you ever get a response to this?

     

    I have 4GB of RAM on my mid 2009 MBP 15 inch.

     

    Kernel_task is eating up 750MB of my RAM, and is about 6GB virtual mem. Why the heck is it taking so much?

     

    Any ideas on how to resolve this please?    

  • by cupofnoise,

    cupofnoise cupofnoise Dec 28, 2011 2:21 AM in response to DChabot
    Level 1 (0 points)
    Dec 28, 2011 2:21 AM in response to DChabot

    I have the same problem since I've upgraged my White Unibody Mid 2010 with 4 GBs from Snow Leopard to Lion.

    It seems to be this is the problem of Lion, not of MB model.

  • by thawking78,

    thawking78 thawking78 Dec 28, 2011 8:41 AM in response to cupofnoise
    Level 1 (0 points)
    Dec 28, 2011 8:41 AM in response to cupofnoise

    Hey cupofnoise, it's not a Lion issue per se — or, at least, the RAM usage that people in this thread are experiencing isn't, because there's plenty of Snow Leopard users amongst them (personally, I'm running Snow Leopard on an early 2011 MacBook Pro). I'm still sticking to the theory that it's the integrated graphics — I installed 8GB of RAM and noticed that kernel_task memory usage went up further afterwards, which seems to make sense as the integrated chip uses more RAM if you have 8GB on board (512MB instead of 384MB).

  • by Mox_Nix,

    Mox_Nix Mox_Nix Dec 28, 2011 2:01 PM in response to wyager
    Level 1 (0 points)
    Dec 28, 2011 2:01 PM in response to wyager

    Integrated graphics may hold the key.  Would like to add a voice to this issue which has plagued my early 2011 MacAir Snow Leopard from the outset.  Large real memory usage by kernal_task that results in page outs and swapping, even when nothing else is being used and after a restart.

  • by duswdav,

    duswdav duswdav Jan 14, 2012 9:57 AM in response to cupofnoise
    Level 1 (0 points)
    Jan 14, 2012 9:57 AM in response to cupofnoise

    i have a mid 10 mbp that i just increased from 4 to 8gb. everything is running ok but i noticed that k_t is now using 400+mb upon boot and right now with 2 browsers open its tat ~600. before the ram upgrade it wasnt that high, in fact firefox was usually at the top of the list of ram hogs. is it just my os(lion before and after upgrade) taking up more ram in proportion with the increase?

     

    edit**

    i honestly don't know what im talking about, just trying to keep my mac healthy

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