2019-kvm-forum/4500-new-qemu-flag.html

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   5 <h1>The fix: raise the victory flag</h1>
   6
   7 <p>
   8   Filler text - need a graphic here showing multiple combinations:
   9
  10   <br>[WZ] = WRITE_ZEROES, normal
  11   <br>[FZ+] = WRITE_ZEROES, successful with FAST_ZERO flag
  12   <br>[FZ-] = WRITE_ZEROES, fails with FAST_ZERO flag
  13   <br>[W...] = WRITE for data
  14
  15 <pre>
  16                   O(1) server             O(n) server
  17 pre-patch         [W...][WZ][W...][WZ]    [W...][WZ..][W...][WZ..]
  18
  19 with fast zero    [FZ+][W...][W...]       [FZ-][W...][WZ..][W...][WZ..]
  20                   (faster)                (marginally slower)
  21 </pre>
  22
  23 Or maybe a graph of demo results:
  24 <pre>
  25      |                                   B
  26    12|
  27      |
  28      |
  29      |
  30      |
  31      |
  32      |
  33      |   A B
  34    8 |                     B                           B          B
  35      |
  36      |
  37      |
  38  t   |
  39  i   |
  40  m   |
  41  e   |                   A                           A
  42    4 |                                 A                        A
  43      |
  44      |
  45      |
  46      |
  47      |
  48      |
  49      |
  50    0 +----------------------------------------------------------------
  51        just WRITE   WRITE_ZEROES     blind         FAST_ZERO  FAST_ZERO
  52                     on every hole    pre-zeroing   missing    supported
  53 </pre>
  54
  55 </p>