)]}'
{
  "commit": "a4e61474240092ab35b8a61e5123bbe2bcd6069b",
  "tree": "51a4858ffc7562126e4d26b32586739e1ff67766",
  "parents": [
    "650cdb50b04ffbeb43490e6c0d8b164e37159e02"
  ],
  "author": {
    "name": "Shaohua Li",
    "email": "shli@kernel.org",
    "time": "Tue Oct 15 09:05:04 2013 +0800"
  },
  "committer": {
    "name": "Jens Axboe",
    "email": "axboe@kernel.dk",
    "time": "Tue Oct 15 09:15:10 2013 -0600"
  },
  "message": "blk-mq: switch to percpu-ida for tag management\n\nUsing percpu-ida to manage blk-mq tags. the percpu-ida has similar algorithm\nlike the blk-mq-tag. The difference is when a cpu can\u0027t allocate tags\nblk-mq-tag uses ipi to purge remote cpu cache and percpu-ida directly purges\nremote cpu cache. In practice (testing null_blk), the percpu-ida approach is\nmuch faster when total tags aren\u0027t enough.\n\nMy test is done in a 2 sockets machine, 12 process cross the 2 sockets. So if\nthere is lock contention or ipi, should be stressed heavily. Testing is done\nfor null-blk.\n\nhw_queue_depth\tnopatch iops\tpatch iops\n64\t\t~800k/s\t\t~1470k/s\n2048\t\t~4470k/s\t~4340k/s\n\nSigned-off-by: Shaohua Li \u003cshli@fusionio.com\u003e\nSigned-off-by: Jens Axboe \u003caxboe@kernel.dk\u003e\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "a115862824a2c279b8a1d9dedfc3fce3ff66a66c",
      "old_mode": 33188,
      "old_path": "block/blk-mq-tag.c",
      "new_id": "d64a02fb1f7307e75bc64410104d22087b04965c",
      "new_mode": 33188,
      "new_path": "block/blk-mq-tag.c"
    }
  ]
}