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    DateMon, 25 Feb 2008 20:05:18 +0530
    FromDhaval Giani <>
    SubjectRe: [PATCH] sched: revert load_balance_monitor()
    On Mon, Feb 25, 2008 at 03:29:59PM +0100, Mike Galbraith wrote:
    > 
    > On Mon, 2008-02-25 at 13:22 +0100, Peter Zijlstra wrote:
    > > Subject: sched: revert load_balance_monitor()
    > > 
    > > The following commit causes a number of serious regressions:
    > > 
    > >   commit 6b2d7700266b9402e12824e11e0099ae6a4a6a79
    > >   Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
    > >   Date:   Fri Jan 25 21:08:00 2008 +0100
    > >   sched: group scheduler, fix fairness of cpu bandwidth allocation for task groups
    > > 
    > > Namely:
    > >  - very frequent wakeups on SMP, reported by PowerTop users.
    > >  - cacheline trashing on (large) SMP
    > >  - some latencies larger than 500ms
    > > 
    > > While there is a mergeable patch to fix the latter, the former issues
    > > are IMHO not fixable in a manner suitable for .25 (we're at -rc3 now).
    > > Hence I propose to revert this patch and try again for .26.
    > > 
    > > ( minimal revert - leaves most of the code present, just removes the activation
    > >   and sysctl interface ).
    > 
    > top - 14:05:56 up 3 min, 16 users,  load average: 4.31, 2.14, 0.85
    > Tasks: 218 total,   5 running, 213 sleeping,   0 stopped,   0 zombie
    > Cpu(s): 35.5%us, 64.5%sy,  0.0%ni,  0.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
    > 
    >   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  P COMMAND
    >  5294 mikeg     20   0  1464  364  304 R   99  0.0   1:00.08 0 chew-max
    >  5278 root      20   0  1464  364  304 R   32  0.0   0:27.86 1 chew-max
    >  5279 root      20   0  1464  360  304 R   32  0.0   0:35.53 1 chew-max
    >  5290 root      20   0  1464  364  304 R   31  0.0   0:29.00 1 chew-max
    > 
    > The minimal revert seems to leave group fairness in a worse state than
    > what the original patch meant to fix.  Maybe a full revert would be
    > better?
    > 
    
    This is funny. The thread should not start. Did the full revert that I
    sent you sometime back work better?
    
    Thanks,
    -- 
    regards,
    Dhaval
    
    
    
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