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<p><strong><span style="font-family:"Calibri",sans-serif;font-weight:normal">Hi DPDK Community,<o:p></o:p></span></strong></p>
<p>I am facing an issue where <strong><span style="font-family:"Calibri",sans-serif">CPU affinity is not working as expected in RHEL8</span></strong> with DPDK 20.05, while it works fine in RHEL7.<o:p></o:p></p>
<p class="MsoNormal"><b>Problem Statement:<o:p></o:p></b></p>
<p class="MsoNormal"><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> </span><span style="font-family:Symbol;mso-ligatures:none;mso-fareast-language:EN-IN">·</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> When running my
program with </span><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none;mso-fareast-language:EN-IN">numactl -C4,5 ./testRTE</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> on
<b>RHEL7</b>, the worker threads correctly bind to the assigned cores.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-ligatures:none;mso-fareast-language:EN-IN">
</span><span style="font-family:Symbol;mso-ligatures:none;mso-fareast-language:EN-IN">·</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> However, on
<b>RHEL8</b>, the worker threads always bind to <b>core 1</b>, ignoring the specified CPU set.<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><span style="mso-ligatures:none;mso-fareast-language:EN-IN"><o:p> </o:p></span></p>
<p class="MsoNormal"><b>Environment Details:<o:p></o:p></b></p>
<ul type="disc">
<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l1 level1 lfo1">
<b><span style="mso-ligatures:none;mso-fareast-language:EN-IN">DPDK Version:</span></b><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> 20.05.0<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l1 level1 lfo1">
<b><span style="mso-ligatures:none;mso-fareast-language:EN-IN">OS:</span></b><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> RHEL8 (Issue) | RHEL7 (Works Fine)<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l1 level1 lfo1">
<b><span style="mso-ligatures:none;mso-fareast-language:EN-IN">CPU Affinity Tool:</span></b><span style="mso-ligatures:none;mso-fareast-language:EN-IN">
</span><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none;mso-fareast-language:EN-IN">numactl -C</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN"><o:p></o:p></span></li></ul>
<p class="MsoNormal"><b>Sample Program: </b>Attached<o:p></o:p></p>
<p class="MsoNormal"><b>Observations:<o:p></o:p></b></p>
<ul type="disc">
<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo2">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">In <b>RHEL7</b>, worker threads correctly bind to cores specified using
</span><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none;mso-fareast-language:EN-IN">numactl -C</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN">.<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo2">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">In <b>RHEL8</b>, the threads always bind to
<b>core 1</b>, ignoring the CPU set.<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo2">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">Could DPDK be overriding the CPU affinity in RHEL8?<o:p></o:p></span></li></ul>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b>Questions:<o:p></o:p></b></p>
<ol start="1" type="1">
<li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">Is there any known change in CPU affinity handling between RHEL7 and RHEL8 affecting DPDK?<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">Does DPDK override thread affinity when
</span><span style="font-size:10.0pt;font-family:"Courier New";mso-ligatures:none;mso-fareast-language:EN-IN">rte_eal_init()</span><span style="mso-ligatures:none;mso-fareast-language:EN-IN"> is called?<o:p></o:p></span></li><li class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l2 level1 lfo3">
<span style="mso-ligatures:none;mso-fareast-language:EN-IN">Is there any workaround or EAL flag to ensure that CPU affinity is respected?<o:p></o:p></span></li></ol>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="mso-ligatures:none;mso-fareast-language:EN-IN">Any insights or suggestions would be greatly appreciated.<o:p></o:p></span></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Rashi Agarwal.<o:p></o:p></p>
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