<story><title>Two Objects Not Namespaced by the Linux Kernel (2017)</title><url>https://blog.jessfraz.com/post/two-objects-not-namespaced-linux-kernel/</url></story><parent_chain><item><author>derefr</author><text>I wonder whether namespacing time would also result in those namespaces being able to have separate &amp;quot;clocks&amp;quot; (time backends? time schedulers?) that progress at different rates, or for different reasons.&lt;p&gt;Being able to put a process into a time namespace with a deterministic &amp;quot;clock&amp;quot; would obviate a large benefit of &lt;a href=&quot;http:&amp;#x2F;&amp;#x2F;www.zerovm.org&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.zerovm.org&amp;#x2F;&lt;/a&gt;.&lt;p&gt;Also, having &amp;quot;clock slew&amp;quot; be a matter of perspective—with processes that &lt;i&gt;can&lt;/i&gt; handle leap seconds seeing them happen instantaneously; and processes that &lt;i&gt;can&amp;#x27;t&lt;/i&gt; handle leap-seconds, seeing slewed time—would be nice. Then you could have different system facilities that care about &lt;i&gt;monotonic&lt;/i&gt; time, vs. &lt;i&gt;synced to calendar&lt;/i&gt; time, vs. &lt;i&gt;one second per second&lt;/i&gt; time, all having that kind of time available to them as &amp;quot;the time&amp;quot;, rather than through different APIs.</text></item></parent_chain><comment><author>rwmj</author><text>Accelerated time might also be a way to test programs.  It&amp;#x27;s similar to techniques used to test planes (by repeatedly pressurising and depressurising them).  It might, for example, reveal race conditions faster in programs that ordinarily do a lot of sleeping.  I wrote a bit more about this (unproven) idea here: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;rwmj.wordpress.com&amp;#x2F;2010&amp;#x2F;10&amp;#x2F;14&amp;#x2F;half-baked-ideas-accelerated-testing-for-vms&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;rwmj.wordpress.com&amp;#x2F;2010&amp;#x2F;10&amp;#x2F;14&amp;#x2F;half-baked-ideas-accel...&lt;/a&gt;</text></comment>
<story><title>Two Objects Not Namespaced by the Linux Kernel (2017)</title><url>https://blog.jessfraz.com/post/two-objects-not-namespaced-linux-kernel/</url></story><parent_chain><item><author>derefr</author><text>I wonder whether namespacing time would also result in those namespaces being able to have separate &amp;quot;clocks&amp;quot; (time backends? time schedulers?) that progress at different rates, or for different reasons.&lt;p&gt;Being able to put a process into a time namespace with a deterministic &amp;quot;clock&amp;quot; would obviate a large benefit of &lt;a href=&quot;http:&amp;#x2F;&amp;#x2F;www.zerovm.org&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.zerovm.org&amp;#x2F;&lt;/a&gt;.&lt;p&gt;Also, having &amp;quot;clock slew&amp;quot; be a matter of perspective—with processes that &lt;i&gt;can&lt;/i&gt; handle leap seconds seeing them happen instantaneously; and processes that &lt;i&gt;can&amp;#x27;t&lt;/i&gt; handle leap-seconds, seeing slewed time—would be nice. Then you could have different system facilities that care about &lt;i&gt;monotonic&lt;/i&gt; time, vs. &lt;i&gt;synced to calendar&lt;/i&gt; time, vs. &lt;i&gt;one second per second&lt;/i&gt; time, all having that kind of time available to them as &amp;quot;the time&amp;quot;, rather than through different APIs.</text></item></parent_chain><comment><author>kbenson</author><text>&amp;gt; Also, having &amp;quot;clock slew&amp;quot; be a matter of perspective—with processes that can handle leap seconds seeing them happen instantaneously; and processes that can&amp;#x27;t handle leap-seconds, seeing slewed time—would be nice.&lt;p&gt;I imagine there might be some really interesting (for meanings of interesting that include &lt;i&gt;shoot me now&lt;/i&gt;) and hard to track down bugs as you deal with inconsistent clocks not just across systems within a network, but processes within a single system.</text></comment>