lkml.org 
[lkml]   [2007]   [Apr]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS]
    Hi Ingo,

    On Sun, Apr 15, 2007 at 07:55:55PM +0200, Ingo Molnar wrote:
    >
    > * Willy Tarreau <w@1wt.eu> wrote:
    >
    > > Well, since I merged the fair-fork patch, I cannot reproduce (in fact,
    > > bash forks 1000 processes, then progressively execs scheddos, but it
    > > takes some time). So I'm rebuilding right now. But I think that Linus
    > > has an interesting clue about GPM and notification before switching
    > > the terminal. I think it was enabled in console mode. I don't know how
    > > that translates to frozen xterms, but let's attack the problems one at
    > > a time.
    >
    > to debug this, could you try to apply this add-on as well:
    >
    > http://redhat.com/~mingo/cfs-scheduler/sched-fair-print.patch
    >
    > with this patch applied you should have a /proc/sched_debug file that
    > prints all runnable tasks and other interesting info from the runqueue.

    I don't know if you have seen my mail from yesterday evening (here). I
    found that changing keventd prio fixed the problem. You may be interested
    in the description. I sent it at 21:01 (+200).

    > [ i've refreshed all the patches on the CFS webpage, so if this doesnt
    > apply cleanly to your current tree then you'll probably have to
    > refresh one of the patches.]

    Fine, I'll have a look. I already had to rediff the sched-fair-fork
    patch last time.

    > The output should look like this:
    >
    > Sched Debug Version: v0.01
    > now at 226761724575 nsecs
    >
    > cpu: 0
    > .nr_running : 3
    > .raw_weighted_load : 384
    > .nr_switches : 13666
    > .nr_uninterruptible : 0
    > .next_balance : 4294947416
    > .curr->pid : 2179
    > .rq_clock : 241337421233
    > .fair_clock : 7503791206
    > .wait_runtime : 2269918379
    >
    > runnable tasks:
    > task | PID | tree-key | -delta | waiting | switches
    > -----------------------------------------------------------------
    > + cat 2179 7501930066 -1861140 1861140 2
    > loop_silent 2149 7503010354 -780852 0 911
    > loop_silent 2148 7503510048 -281158 280753 918

    Nice.

    > now for your workload the list should be considerably larger. If there's
    > starvation going on then the 'switches' field (number of context
    > switches) of one of the tasks would never increase while you have this
    > 'cannot switch consoles' problem.
    >
    > maybe you'll have to unapply the fair-fork patch to make it trigger
    > again. (fair-fork does not fix anything, so it probably just hides a
    > real bug.)
    >
    > (i'm meanwhile busy running your scheddos utilities to reproduce it
    > locally as well :)

    I discovered I had the frame-buffer enabled (I did not notice it first
    because I do not have the logo and the resolution is the same as text).
    It's matroxfb with a G400, if that can help. It may be possible that
    it needs some CPU that it cannot get to clear the display before
    switching, I don't know.

    However I won't try this right now, I'm deep in userland at the moment.

    Regards,
    Willy

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-04-15 20:09    [W:7.005 / U:0.196 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site