)]}'
{
  "commit": "b0e5c77903fd717cc5eb02b7b8f5de3c869efc49",
  "tree": "1c76da4dbb0ff5c2171dfa3c2e6834070014eb3c",
  "parents": [
    "97ac984d2feec885d10f900591431088eab42021"
  ],
  "author": {
    "name": "Suresh Siddha",
    "email": "suresh.b.siddha@intel.com",
    "time": "Mon Feb 06 18:32:20 2012 -0800"
  },
  "committer": {
    "name": "Ingo Molnar",
    "email": "mingo@elte.hu",
    "time": "Wed Feb 22 11:49:40 2012 +0100"
  },
  "message": "x86/tsc: Reduce the TSC sync check time for core-siblings\n\nFor each logical CPU that is coming online, we spend 20msec for\nchecking the TSC synchronization. And as this is done\nsequentially for each logical CPU boot, this time gets added up\ndepending on the number of logical CPU\u0027s supported by the\nplatform.\n\nMinimize this by using the socket topology information.\n\nIf the target CPU coming online doesn\u0027t have any of its\ncore-siblings online, a timeout of 20msec will be used for the\nTSC-warp measurement loop. Otherwise a smaller timeout of 2msec\nwill be used, as we have some information about this socket\nalready (and this information grows as we have more and more\nlogical-siblings in that socket).\n\nIdeally we should be able to skip the TSC sync check on the\nother core-siblings, if the first logical CPU in a socket passed\nthe sync test. But as the TSC is per-logical CPU and can\npotentially be modified wrongly by the bios before the OS boot,\nTSC sync test for smaller duration should be able to catch such\nerrors. Also this will catch the condition where all the cores\nin the socket doesn\u0027t get reset at the same time.\n\nFor example, with this modification, time spent in TSC sync\nchecks on a 4 socket 10-core with HT system gets reduced from\n1580msec to 212msec.\n\nSigned-off-by: Suresh Siddha \u003csuresh.b.siddha@intel.com\u003e\nAcked-by: Arjan van de Ven \u003carjan@linux.intel.com\u003e\nAcked-by: Peter Zijlstra \u003ca.p.zijlstra@chello.nl\u003e\nCc: Jack Steiner \u003csteiner@sgi.com\u003e\nCc: venki@google.com\nCc: Linus Torvalds \u003ctorvalds@linux-foundation.org\u003e\nCc: Andrew Morton \u003cakpm@linux-foundation.org\u003e\nLink: http://lkml.kernel.org/r/1328581940.29790.20.camel@sbsiddha-desk.sc.intel.com\nSigned-off-by: Ingo Molnar \u003cmingo@elte.hu\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "9eba29b46cb714481e7973da630c20e525f45379",
      "old_mode": 33188,
      "old_path": "arch/x86/kernel/tsc_sync.c",
      "new_id": "fc25e60a588458078e7d66a4ba8a7e995624b585",
      "new_mode": 33188,
      "new_path": "arch/x86/kernel/tsc_sync.c"
    }
  ]
}