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<base href="https://bugs.freedesktop.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Reading amdgpu_pm_info causes stutter with Linux 4.12-rc"
href="https://bugs.freedesktop.org/show_bug.cgi?id=101182">101182</a>
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<th>Summary</th>
<td>Reading amdgpu_pm_info causes stutter with Linux 4.12-rc
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
</tr>
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<th>Version</th>
<td>DRI git
</td>
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<th>Hardware</th>
<td>Other
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>DRM/AMDgpu
</td>
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>haagch@frickel.club
</td>
</tr></table>
<p>
<div>
<pre>A stutter once wouldn't be so bad, but apps like radeon-profile repeatedly read
this file, so rendering stutters constantly.
You will have a hard time spotting it in the average fps graph, but with my
(still very inaccurate) low-fps patch at
<a href="https://github.com/ChristophHaag/mesa-mesa/commit/e097b91a85c85718576589402e075e7f5668e68c">https://github.com/ChristophHaag/mesa-mesa/commit/e097b91a85c85718576589402e075e7f5668e68c</a>
it's very visible that there is at least one frame that's delayed a lot each
time amdgpu_pm_info is read.
The GPU load does give an independent hint that something is wrong though.
To reproduce:
run glxgears
run sudo watch --interval=.3 cat /sys/kernel/debug/dri/0/amdgpu_pm_info
observe stuttering in glxgears.
RX 480, Linux 4.12-rc2.
I haven't tested 4.11 to confirm, but if I remember correctly, this happens in
mainline since 4.12.</pre>
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</p>
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