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      <base href="https://bugs.freedesktop.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Performance degradation when one display is in rotation"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=93864">93864</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Performance degradation when one display is in rotation
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>xorg
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>7.7 (2012.06)
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86 (IA32)
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (All)
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>major
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Driver/intel
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>chris@chris-wilson.co.uk
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>franck.delache@grassvalley.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-gfx-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>My system has chipset 915GM configured in dual-display. One of the display is
configured in rotation.
I am running a Java application using XRender pipeline which does rendering at
30fps.

With Intel driver 2.99.917, the rendering is fluid and top shows about 30% of
idle CPU.
With Intel driver 2.99.917+git20151217, the rendering is not fluid and top
shows 30% in wa state (0% idle)

I managed to git bisect the culprit commit 9a311f9
sna: Throw away the TearFree damage if it grows too big

Reverting this commit makes the system behave normally (rendering is back to
30fps and CPU is 30% idle).

Note that when both displays are in normal orientation, I do not see any
performance issue.</pre>
        </div>
      </p>
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