<story><title>A Look at the CPU Security Mitigation Costs Three Years After Spectre/Meltdown</title><url>https://www.phoronix.com/scan.php?page=article&amp;item=3-years-specmelt&amp;num=1</url></story><parent_chain></parent_chain><comment><author>tux</author><text>So can someone please explain to me if its better to use &amp;quot;mitigations=off&amp;quot; with Linux Kernel 5.10 or have the default from kernel with &amp;quot;AMD Phenom II X4 955 Processor&amp;quot;? By running &amp;quot;lscpu&amp;quot; I see only two lines in default mode (not using &amp;quot;mitigations=off&amp;quot; right now), everything else &amp;quot;Not affected&amp;quot;;&lt;p&gt;&lt;pre&gt;&lt;code&gt;  Vulnerability Spectre v1: Mitigation; usercopy&amp;#x2F;swapgs barriers and __user pointer sanitization
  Vulnerability Spectre v2: Mitigation; Full AMD retpoline, STIBP disabled, RSB filling
&lt;/code&gt;&lt;/pre&gt;
By having those it will affect my CPU perferomance? Will applying &amp;quot;mitigations=off&amp;quot; help with perfermance? Also by having &amp;quot;mitigations=off&amp;quot; what are the real security implications? Thank you for your help!</text></comment>
<story><title>A Look at the CPU Security Mitigation Costs Three Years After Spectre/Meltdown</title><url>https://www.phoronix.com/scan.php?page=article&amp;item=3-years-specmelt&amp;num=1</url></story><parent_chain></parent_chain><comment><author>pstrateman</author><text>The context switching thing is the biggest.&lt;p&gt;If you have something that&amp;#x27;s just making a huge number of syscall&amp;#x27;s in a tight loop the mitigations absolutely dumpster performance.</text></comment>