Meaning of "cached" when top utility is run - Powerpc

This is a discussion on Meaning of "cached" when top utility is run - Powerpc ; When I run top, I see: Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached Load average: 0.33, 0.25, 0.21 (State: S=sleeping R=running, W=waiting) What does "10584K cached" mean? My system crashes once I get above 12000K cached. ...

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Thread: Meaning of "cached" when top utility is run

  1. Meaning of "cached" when top utility is run

    When I run top, I see:

    Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    Load average: 0.33, 0.25, 0.21 (State: S=sleeping R=running,
    W=waiting)

    What does "10584K cached" mean? My system crashes once I get above
    12000K cached. Is there a configuration variable I can change
    somewhere to stop it from crashing when cached reaches 12000K?

    I am running Linux 2.6.10 on powerpc.

  2. Re: Meaning of "cached" when top utility is run

    On Aug 18, 7:28*pm, Bill wrote:
    > When I run top, I see:
    >
    > Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    > Load average: 0.33, 0.25, 0.21 * *(State: S=sleeping R=running,
    > W=waiting)
    >
    > What does "10584K cached" mean? *My system crashes once I get above
    > 12000K cached. *Is there a configuration variable I can change
    > somewhere to stop it from crashing when cached reaches 12000K?
    >
    > I am running Linux 2.6.10 on powerpc.


    That might not be a stable kernel. In debian we used 2.6.8 and then
    pretty quickly went to 2.6.18 and now in the 20s. There was a major
    transition between 2.6.15 and 2.6.18.

    You should try a recent kernel.

    What model machine do you have and what processor ? Are you
    sure all your RAM is really good ? You could try moving/removing a
    card.
    Small RAM modules are sometimes not tolerated well anymore (small
    means 16-32MB) -- if you have any of these best to try taking
    them out if you are having crashes.

    That's about all I can say unless you tell me the particular machine
    and date/version/name of your distribution.

  3. Re: Meaning of "cached" when top utility is run

    On Aug 18, 7:28*pm, Bill wrote:
    > When I run top, I see:
    >
    > Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    > Load average: 0.33, 0.25, 0.21 * *(State: S=sleeping R=running,
    > W=waiting)
    >
    > What does "10584K cached" mean? *My system crashes once I get above
    > 12000K cached. *Is there a configuration variable I can change
    > somewhere to stop it from crashing when cached reaches 12000K?
    >
    > I am running Linux 2.6.10 on powerpc.


    Sorry, to answer your question: cached/buffers means memory that
    is used to save on disk-i/o I believe. To be able to reuse libraries
    rather
    than reread them is much faster. Also not to write to disk right away.
    Perhaps too some video buffer if you are low on video memory.

    Usually the devices can be told to read/write from/to a memory space
    and the cpu can go along its business if it can.

  4. Re: Meaning of "cached" when top utility is run

    On Aug 19, 8:18*pm, tortoise wrote:
    > On Aug 18, 7:28*pm, Bill wrote:
    >
    > > When I run top, I see:

    >
    > > Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    > > Load average: 0.33, 0.25, 0.21 * *(State: S=sleeping R=running,
    > > W=waiting)

    >
    > > What does "10584K cached" mean? *My system crashes once I get above
    > > 12000K cached. *Is there a configuration variable I can change
    > > somewhere to stop it from crashing when cached reaches 12000K?

    >
    > > I am running Linux 2.6.10 on powerpc.

    >
    > That might not be a stable kernel. In debian we used 2.6.8 and then
    > pretty quickly went to 2.6.18 and now in the 20s. There was a major
    > transition between 2.6.15 and 2.6.18.
    >
    > You should try a recent kernel.
    >
    > What model machine do you have and what processor ? Are you
    > sure all your RAM is really good ? You could try moving/removing a
    > card.
    > Small RAM modules are sometimes not tolerated well anymore (small
    > means 16-32MB) -- if you have any of these best to try taking
    > them out if you are having crashes.
    >
    > That's about all I can say unless you tell me the particular machine
    > and date/version/name of your distribution.


    It's a custom board with 128 MB of RAM and an MPC8248 processor.
    Others have said to try a recent kernel. Do you have a specific
    reason why a newer kernel will fix the problem?

  5. Re: Meaning of "cached" when top utility is run

    Bill wrote:
    > On Aug 19, 8:18 pm, tortoise wrote:
    >> On Aug 18, 7:28 pm, Bill wrote:
    >>
    >>> When I run top, I see:
    >>> Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    >>> Load average: 0.33, 0.25, 0.21 (State: S=sleeping R=running,
    >>> W=waiting)
    >>> What does "10584K cached" mean? My system crashes once I get above
    >>> 12000K cached. Is there a configuration variable I can change
    >>> somewhere to stop it from crashing when cached reaches 12000K?
    >>> I am running Linux 2.6.10 on powerpc.

    >> That might not be a stable kernel. In debian we used 2.6.8 and then
    >> pretty quickly went to 2.6.18 and now in the 20s. There was a major
    >> transition between 2.6.15 and 2.6.18.
    >>
    >> You should try a recent kernel.
    >>
    >> What model machine do you have and what processor ? Are you
    >> sure all your RAM is really good ? You could try moving/removing a
    >> card.
    >> Small RAM modules are sometimes not tolerated well anymore (small
    >> means 16-32MB) -- if you have any of these best to try taking
    >> them out if you are having crashes.
    >>
    >> That's about all I can say unless you tell me the particular machine
    >> and date/version/name of your distribution.

    >
    > It's a custom board with 128 MB of RAM and an MPC8248 processor.
    > Others have said to try a recent kernel. Do you have a specific
    > reason why a newer kernel will fix the problem?


    It is always best to use the latest version, because of various bugs
    being fixed.
    Anyway, he said you should try - not that it is going to fix your
    problem. It might be something else

  6. Re: Meaning of "cached" when top utility is run

    On Aug 19, 10:40*pm, Bill wrote:
    > On Aug 19, 8:18*pm, tortoise wrote:
    >
    >
    >
    > > On Aug 18, 7:28*pm, Bill wrote:

    >
    > > > When I run top, I see:

    >
    > > > Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    > > > Load average: 0.33, 0.25, 0.21 * *(State: S=sleeping R=running,
    > > > W=waiting)

    >
    > > > What does "10584K cached" mean? *My system crashes once I get above
    > > > 12000K cached. *Is there a configuration variable I can change
    > > > somewhere to stop it from crashing when cached reaches 12000K?

    >
    > > > I am running Linux 2.6.10 on powerpc.

    >
    > > That might not be a stable kernel. In debian we used 2.6.8 and then
    > > pretty quickly went to 2.6.18 and now in the 20s. There was a major
    > > transition between 2.6.15 and 2.6.18.

    >
    > > You should try a recent kernel.

    >
    > > What model machine do you have and what processor ? Are you
    > > sure all your RAM is really good ? You could try moving/removing a
    > > card.
    > > Small RAM modules are sometimes not tolerated well anymore (small
    > > means 16-32MB) -- if you have any of these best to try taking
    > > them out if you are having crashes.

    >
    > > That's about all I can say unless you tell me the particular machine
    > > and date/version/name of your distribution.

    >
    > It's a custom board with 128 MB of RAM and an MPC8248 processor.
    > Others have said to try a recent kernel. *Do you have a specific
    > reason why a newer kernel will fix the problem?


    I don't think 2.6.10 was a stable kernel, unless the manufacturer
    supplied it but even then it does not look good to me. Its probably
    just so you can test it and know it more or less works.

    depending on whether you have upgraded any other software
    on it then things could really be broken.

    If you install a stable release and you find stuff like this happening
    then if I were you I would contact the manufacturer. May be
    there is a hardware problem, but as I said before check that
    your RAM is not defective !

    Maybe there are kernel parameters to fix the cache size, but
    since that was experimental in 2.6.10, you really should get
    a newer kernel. Then go to some kernel gurus and ask them
    about setting it dynamically, if you must. But it is not so
    good an idea, it will slow it down badly.


  7. Re: Meaning of "cached" when top utility is run

    Also the size of the shared memory (ipcs -m) is included into the cached
    number.

    Regards,

    Sani



    "tortoise" wrote in message
    news:46d8ea84-634e-4165-a029-73f31e697f10@b2g2000prf.googlegroups.com...
    On Aug 18, 7:28 pm, Bill wrote:
    > When I run top, I see:
    >
    > Mem: 27072K used, 100256K free, 0K shrd, 0K buff, 10584K cached
    > Load average: 0.33, 0.25, 0.21 (State: S=sleeping R=running,
    > W=waiting)
    >
    > What does "10584K cached" mean? My system crashes once I get above
    > 12000K cached. Is there a configuration variable I can change
    > somewhere to stop it from crashing when cached reaches 12000K?
    >
    > I am running Linux 2.6.10 on powerpc.


    Sorry, to answer your question: cached/buffers means memory that
    is used to save on disk-i/o I believe. To be able to reuse libraries
    rather
    than reread them is much faster. Also not to write to disk right away.
    Perhaps too some video buffer if you are low on video memory.

    Usually the devices can be told to read/write from/to a memory space
    and the cpu can go along its business if it can.


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