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 QuickTimeX,

    QuickTimeX QuickTimeX Jul 28, 2011 8:38 PM in response to DChabot
    Level 1 (0 points)
    Jul 28, 2011 8:38 PM in response to DChabot

    I am having the same issue. And a clean install of Snow Leopard a few months ago did not solve the issue at all. The memory usage of kernel_task was about 700MB up on boot.

     

    Now I am running Lion, it is over 900MB upon boot. This is ridiculous. Also Safari is a RAM hog as well. Pretty fast I run out of memory even though I have 8GB of RAM.

     

    I am not sure whether there is something wrong with Mac OS X but this is definitely affecting other program's performance.

  • by QuickTimeX,

    QuickTimeX QuickTimeX Jul 28, 2011 9:31 PM in response to QuickTimeX
    Level 1 (0 points)
    Jul 28, 2011 9:31 PM in response to QuickTimeX

    I have "resolved" the issue.

     

    The key is that first of all, Intel integrated graphic cards uses 512MB RAM. Previous generation intel graphics may only use 128MB, or 265MB.

     

    Secondly, you can boot into safe mode and compare what kexts are loaded, and then boot normally and see what's the additional stuff loaded.

     

    When booted into Safe Mode, I see horrible graphic performance, suggesting the graphic cards are probably not really used. And in that mode, my kernel_task takes about <400MB RAM.

     

    So 350 MB + 512 MB = almost 900MB RAM. Then I found a list of additional kext loaded. So those push the kernel_task to over 900MB.

     

    I hope that resolves the problem. I wish I can turn off Intel integrated graphics. The ATi card in my MBP only has 256MB and is more powerful. There is no reason why Intel graphics needs 512MB.

     

    Attached image shows the additional kexts loaded. Those include ATI and Intel kexts.

     

    Screen Shot 2011-07-28 at 9.22.43 PM.PNG

  • by wyager,

    wyager wyager Jul 28, 2011 9:41 PM in response to QuickTimeX
    Level 1 (0 points)
    Jul 28, 2011 9:41 PM in response to QuickTimeX

    I don't think that's it. First off, I'm pretty sure the intel graphics only use 384 megs of ram. That doesn't account for 900 megs used by k_t. Second, the biggest kext loaded in normal boot mode is the ATI controller kext, which is only a few megs worth of RAM. That's why graphics were bad, it's because safe mode uses low-quality graphics drivers.

  • by QuickTimeX,

    QuickTimeX QuickTimeX Jul 28, 2011 9:42 PM in response to wyager
    Level 1 (0 points)
    Jul 28, 2011 9:42 PM in response to wyager

    How much intel graphics use depends on your model. On my MBP 15" 2011, it uses 512MB. You can see it from system profile (now called system report... in Lion).

  • by wyager,

    wyager wyager Jul 28, 2011 9:53 PM in response to QuickTimeX
    Level 1 (0 points)
    Jul 28, 2011 9:53 PM in response to QuickTimeX

    I have the same model... Do the graphics really scale usage with available RAM? Can someone test this? Because we may have our answer.

    Screen Shot 2011-07-28 at 11.50.51 PM.png

  • by QuickTimeX,

    QuickTimeX QuickTimeX Jul 28, 2011 9:53 PM in response to wyager
    Level 1 (0 points)
    Jul 28, 2011 9:53 PM in response to wyager

    It may have something to do with total RAM you have.

    The more you have, the more it takes...

     

    Intel HD Graphics 3000:

     

      Chipset Model:          Intel HD Graphics 3000

      Type:          GPU

      Bus:          Built-In

      VRAM (Total):          512 MB

      Vendor:          Intel (0x8086)

      Device ID:          0x0116

      Revision ID:          0x0009

      gMux Version:          1.9.23

      Displays:

    Display Connector:

  • by wyager,

    wyager wyager Jul 28, 2011 9:57 PM in response to QuickTimeX
    Level 1 (0 points)
    Jul 28, 2011 9:57 PM in response to QuickTimeX

    Well, problem "solved". I wish we could free up that RAM, however.

  • by QuickTimeX,

    QuickTimeX QuickTimeX Jul 28, 2011 9:58 PM in response to wyager
    Level 1 (0 points)
    Jul 28, 2011 9:58 PM in response to wyager

    me too. how much RAM is your kernel_task using?

    do you have total 4GB?

  • by wyager,

    wyager wyager Jul 28, 2011 10:05 PM in response to QuickTimeX
    Level 1 (0 points)
    Jul 28, 2011 10:05 PM in response to QuickTimeX

    Yep, 4 gigs of RAM installed. My k_t is taking up 578 megs of RAM.

     

    It is odd though, I don't remember ever seeing  k_t using as much RAM as the integrated graphics was supposed to use on older macs. Maybe I just wasn't paying attention.

  • by rodknocker,

    rodknocker rodknocker Jul 29, 2011 10:24 AM in response to wyager
    Level 1 (5 points)
    Jul 29, 2011 10:24 AM in response to wyager

    Images are from today.

     

    kernel_task around 1 GB.

     

    MBP 2011, 8 GB RAM

     

    aktivätsanzeige.jpg

    My MBP uses at the moment the AMD Radeon video card.

     

    graphic1.jpg

     

    And the Intel HD Graphics still uses 512 MB Video RAM. I think this is problem why the kernel_task allocate so much RAM.

     

    graphic2.jpg

  • by thawking78,

    thawking78 thawking78 Jul 29, 2011 11:19 AM in response to DChabot
    Level 1 (0 points)
    Jul 29, 2011 11:19 AM in response to DChabot

    Yeah, I think that's the thing — that RAM stays reserved for the Intel GPU whether or not it's in use. I guess it's so there isn't an epic page in/out if a lot of your RAM is already in use by other applications when a switch to the HD 3000 occurs — I imagine that'd result in the switch appearing awfully sluggish, which isn't the seamless automatic switching experience Apple wants to promote. So I guess it's easier to keep a set amount of RAM for the integrated GPU, no matter what. It'd be nice if you could allocate the amount manually, though, and reduce it if you so desire. I wonder if there's a way to do this...?

  • by rodknocker,

    rodknocker rodknocker Jul 29, 2011 11:37 AM in response to thawking78
    Level 1 (5 points)
    Jul 29, 2011 11:37 AM in response to thawking78

    Yes, but on non-2011 MBPs, there isn't such usage of RAM for the kernel_task.

  • by MacJoseph,

    MacJoseph MacJoseph Jul 29, 2011 11:40 AM in response to QuickTimeX
    Level 3 (595 points)
    Jul 29, 2011 11:40 AM in response to QuickTimeX

    QuickTimeX

     

    Strange you shoud be running out of RAM with 8GB. I always have 5.9 or 6GB free. Safari is a memory hog I agree that's why I don't use it. It seems nowadays all browsers are memory hogs Chrome, FF and Safari. I personally use FF 5.01. Safari runs and starts a process called webprocess which hogs RAM along with Safari. I also agree this kernel task is a problem, but it hasn't affected my system performance one bit. As I post this kernel task is using 692MB 82 threads and the CPU is only about 1.0%

     

    I don't know what the solution is. But the people with only 4GB of RAM can easily upgrade to 8GB for as little as $44.00 as I just did. I bought 8GB of Corasir RAM from Amazon it was $54.00 and $44.00 after a $10.00 mail in rebate. The shipping is free from Amazon. Anyone can Google Corsair 8GB RAM upgrade and find the offer.

     

    I haven't  had any issues using the Corsair RAM.

     

    Joseph

  • by rodknocker,

    rodknocker rodknocker Jul 29, 2011 11:41 AM in response to MacJoseph
    Level 1 (5 points)
    Jul 29, 2011 11:41 AM in response to MacJoseph

    That isn't the point

     

    I upgraded, for sure, but it is only a kind of "workaround".

     

    The problem is still there.

  • by eww,

    eww eww Jul 29, 2011 12:16 PM in response to wyager
    Level 9 (52,994 points)
    Jul 29, 2011 12:16 PM in response to wyager

    Does anyone have a shred of proof that performance actually does go up with more RAM consumption? All I've heard so far is guesswork.

     

    Does anyone have a shred of proof that it goes down?

     

    If not, what's all the fuss?


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