• Peter Zijlstra's avatar
    sched/nohz: Fix rq->cpu_load[] calculations · 556061b0
    Peter Zijlstra authored
    While investigating why the load-balancer did funny I found that the
    rq->cpu_load[] tables were completely screwy.. a bit more digging
    revealed that the updates that got through were missing ticks followed
    by a catchup of 2 ticks.
    
    The catchup assumes the cpu was idle during that time (since only nohz
    can cause missed ticks and the machine is idle etc..) this means that
    esp. the higher indices were significantly lower than they ought to
    be.
    
    The reason for this is that its not correct to compare against jiffies
    on every jiffy on any other cpu than the cpu that updates jiffies.
    
    This patch cludges around it by only doing the catch-up stuff from
    nohz_idle_balance() and doing the regular stuff unconditionally from
    the tick.
    Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: pjt@google.com
    Cc: Venkatesh Pallipadi <venki@google.com>
    Link: http://lkml.kernel.org/n/tip-tp4kj18xdd5aj4vvj0qg55s2@git.kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    556061b0
sched.h 29.5 KB