)]}'
{
  "commit": "83cd4fe27ad8446619b2e030b171b858501de87d",
  "tree": "81c7d26f4f00139ae355017239371d91cc4b2aef",
  "parents": [
    "fdf3e95d3916f18bf8703fb065499fdbc4dfe34c"
  ],
  "author": {
    "name": "Venkatesh Pallipadi",
    "email": "venki@google.com",
    "time": "Fri May 21 17:09:41 2010 -0700"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@elte.hu",
    "time": "Wed Jun 09 10:34:52 2010 +0200"
  },
  "message": "sched: Change nohz idle load balancing logic to push model\n\nIn the new push model, all idle CPUs indeed go into nohz mode. There is\nstill the concept of idle load balancer (performing the load balancing\non behalf of all the idle cpu\u0027s in the system). Busy CPU kicks the nohz\nbalancer when any of the nohz CPUs need idle load balancing.\nThe kickee CPU does the idle load balancing on behalf of all idle CPUs\ninstead of the normal idle balance.\n\nThis addresses the below two problems with the current nohz ilb logic:\n* the idle load balancer continued to have periodic ticks during idle and\n  wokeup frequently, even though it did not have any rebalancing to do on\n  behalf of any of the idle CPUs.\n* On x86 and CPUs that have APIC timer stoppage on idle CPUs, this\n  periodic wakeup can result in a periodic additional interrupt on a CPU\n  doing the timer broadcast.\n\nAlso currently we are migrating the unpinned timers from an idle to the cpu\ndoing idle load balancing (when all the cpus in the system are idle,\nthere is no idle load balancing cpu and timers get added to the same idle cpu\nwhere the request was made. So the existing optimization works only on semi idle\nsystem).\n\nAnd In semi idle system, we no longer have periodic ticks on the idle load\nbalancer CPU. Using that cpu will add more delays to the timers than intended\n(as that cpu\u0027s timer base may not be uptodate wrt jiffies etc). This was\ncausing mysterious slowdowns during boot etc.\n\nFor now, in the semi idle case, use the nearest busy cpu for migrating timers\nfrom an idle cpu.  This is good for power-savings anyway.\n\nSigned-off-by: Venkatesh Pallipadi \u003cvenki@google.com\u003e\nSigned-off-by: Suresh Siddha \u003csuresh.b.siddha@intel.com\u003e\nSigned-off-by: Peter Zijlstra \u003ca.p.zijlstra@chello.nl\u003e\nCc: Thomas Gleixner \u003ctglx@linutronix.de\u003e\nLKML-Reference: \u003c1274486981.2840.46.camel@sbs-t61.sc.intel.com\u003e\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\n",
  "tree_diff": [
    {
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      "old_path": "include/linux/sched.h",
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      "new_path": "include/linux/sched.h"
    },
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      "new_path": "kernel/hrtimer.c"
    },
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      "new_path": "kernel/sched.c"
    },
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      "old_path": "kernel/sched_fair.c",
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      "new_path": "kernel/sched_fair.c"
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      "old_path": "kernel/time/tick-sched.c",
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      "new_path": "kernel/time/tick-sched.c"
    },
    {
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      "new_path": "kernel/timer.c"
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}