<story><title>The real realtime preemption end game</title><url>https://lwn.net/SubscriberLink/951337/e9139cdb65a9cb93/</url></story><parent_chain><item><author>tyingq</author><text>I wonder if this being fixed will result in it displacing some notable amount of made-for-realtime hardware&amp;#x2F;software combos.  Especially since there&amp;#x27;s now lots of cheap, relatively low power, and high clock rate ARM and x86 chips to choose from. With the clock rates so high, perfect real-time becomes less important as you would often have many cycles to spare for misses.&lt;p&gt;I understand it&amp;#x27;s less elegant, efficient, etc. But sometimes commodity wins over correctness.</text></item></parent_chain><comment><author>tuetuopay</author><text>The thing is, stuff that require hard realtime cannot satisfy with &amp;quot;many cycles to spare for misses&amp;quot;. And CPU cycles is not the whole story. A badly made task could lock down the kernel not doing anything useful. The point of hard realtime is &amp;quot;nothing cannot prevent this critical task from running&amp;quot;.&lt;p&gt;For automotive and aerospace, you really want the control systems to be able to run no matter what.</text></comment>
<story><title>The real realtime preemption end game</title><url>https://lwn.net/SubscriberLink/951337/e9139cdb65a9cb93/</url></story><parent_chain><item><author>tyingq</author><text>I wonder if this being fixed will result in it displacing some notable amount of made-for-realtime hardware&amp;#x2F;software combos.  Especially since there&amp;#x27;s now lots of cheap, relatively low power, and high clock rate ARM and x86 chips to choose from. With the clock rates so high, perfect real-time becomes less important as you would often have many cycles to spare for misses.&lt;p&gt;I understand it&amp;#x27;s less elegant, efficient, etc. But sometimes commodity wins over correctness.</text></item></parent_chain><comment><author>binary132</author><text>I get the sense that applications with true realtime requirements generally have hard enough requirements that they cannot allow even the remote possibility of failure.  Think avionics, medical devices, automotive, military applications.&lt;p&gt;If you really need realtime, then you &lt;i&gt;really need&lt;/i&gt; it and &amp;quot;close enough&amp;quot; doesn&amp;#x27;t really exist.&lt;p&gt;This is just my perception as an outsider though.</text></comment>