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<base href="https://bugs.freedesktop.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - R9 290 low performance in Linux 4.7"
href="https://bugs.freedesktop.org/show_bug.cgi?id=97260">97260</a>
</td>
</tr>
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<th>Summary</th>
<td>R9 290 low performance in Linux 4.7
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Keywords</th>
<td>regression
</td>
</tr>
<tr>
<th>Severity</th>
<td>major
</td>
</tr>
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<th>Priority</th>
<td>high
</td>
</tr>
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<th>Component</th>
<td>DRM/Radeon
</td>
</tr>
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>magolobel@yahoo.com.br
</td>
</tr></table>
<p>
<div>
<pre>Starting with Linux Kernel 4.7, the Radeon R9 290 started showing very low
performance, about 20/30% of what is available up to kernel 4.6. As can be seen
in this article, the performance regression started even before the launch of
kernel 4.7 RC1, using Alex Deucher's drm-next-4.7 branch:
<a href="http://www.phoronix.com/scan.php?page=article&item=radeon-drm-next-47&num=1">http://www.phoronix.com/scan.php?page=article&item=radeon-drm-next-47&num=1</a>
Some time later it was speculated that the problem may be with DPM:
<a href="http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.7-R9-290-Regression">http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.7-R9-290-Regression</a>
To replicate the bug, install Ubuntu 16.04 64bits and install kernel 4.7 from
here (preferably above rc5):
<a href="http://kernel.ubuntu.com/~kernel-ppa/mainline/">http://kernel.ubuntu.com/~kernel-ppa/mainline/</a>
The performance regression will show right away. Rebooting the system and
choosing a kernel version up to 4.6 will fix the bug.</pre>
</div>
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