Re: Constant 20% CPU load after upgrade to fc2

From: Rud Holmgren (fc2_at_tytte.dk)
Date: 06/13/04

  • Next message: Greg Swallow: "Building a Fedora Beowulf" 
    Date: Sun, 13 Jun 2004 21:01:59 +0200
To: fedora-forums@genesis-x.nildram.co.uk, For users of Fedora Core releases <fedora-list@redhat.com>

    Keith G. Robertson-Turner wrote:
    > On Sun, 13 Jun 2004 13:14:29 +0200, Rud Holmgren wrote:
    >
    >
    >>Having just upgraded my fc1 installation to fc2 I experience that the CPU
    >>is constantly loaded at about 20% average. On the system monitor applet
    >>the load appears as spikes when using a 0.5 sec update interval. The
    >>spikes are neither regularly spaced nor equal in height. When running top
    >>in a terminal it reports the average user space load at about 20%, approx
    >>1% system load, and about 80% idle time. No process in the process list
    >>eat more than 1%-2%.
    >>
    >>My guess is that some process is started regularly that eats up a lot of
    >>resources and then dies. I have tried catching this - without any luck. I
    >>have some of the kernel userspace helper threads under suspicion (a
    >>khelper). It's kind'a frustrating so I hope somebody has an idea at to
    >>what is happening.
    >
    >
    > Try the following:
    >
    > 1.
    > Check your root mail for failed cron jobs.
    >
    > 2.
    > Check /var/log/messages
    >
    > 3.
    > init 3
    > startx >~/x.log 2>&1
    > Then in X ...
    > tail -f ~/x.log
    > and in another terminal
    > tail -f /var/log/messages
    >
    > Might shed some light on the problem ...
    >
    > IME the initial prelink on virgin FC2 systems takes an order of magnitude
    > longer than on FC1, but that might have a lot to do with the FC2
    > v.everything install having more packages (more to prelink). Could be
    > that; have you checked /var/log/prelink.log? Although that wouldn't tell
    > you if it segfaulted.
    >
    > -
    > K.
    >
    >

    Well, after further investigation it turns out that
    the kernel repeatedly tries to modprobe char_major_2_N
    for a range of N's. It does it through the khelper
    userspace kernel helper but with such high priority
    that top can't catch it. I had to write my own little
    piece of Ruby to catch it! The strange thing is that
    nothing appears in the logs. And even more strange:
    char_major_2 is old-style pseudo-tty masters. Why
    does the kernel insist on loading modules for these?

    I have a colleague that experience precisely the same
    thing on his recent upgrade to fc2. We both started
    with rh8, upgraded to fc1 and now to fc2. Wonder if
    it is the upgrades that does it?

    /rud 

    -- 
fedora-list mailing list
fedora-list@redhat.com
To unsubscribe: http://www.redhat.com/mailman/listinfo/fedora-list
  • Next message: Greg Swallow: "Building a Fedora Beowulf"