https://docs.matildes.dev/tags/system-administration/Recent content in System-Administration on Samuel Matildes - Knowledge BaseHugoenTue, 26 May 2026 14:15:13 +0100https://docs.matildes.dev/linux/kernel/cpu-statistics/Tue, 14 Jan 2025 00:00:00 +0000https://docs.matildes.dev/linux/kernel/cpu-statistics/<p><i class="fas fa-microchip" aria-hidden="true"></i> Kernel-Level CPU Time Accounting</p> <h2 id="summary">Summary<a class="td-heading-self-link" href="#summary" aria-label="Heading self-link"></a></h2> <p>The Linux kernel maintains precise, per-CPU time accounting across ten distinct execution contexts. These statistics, exposed via <code>/proc/stat</code>, represent cumulative jiffy counters (typically 1/100th or 1/1000th of a second) since system boot. Understanding these counters is essential for performance analysis, capacity planning, and diagnosing CPU contention, I/O bottlenecks, interrupt storms, and virtualization overhead.</p> <h2 id="the-procstat-interface">The /proc/stat Interface<a class="td-heading-self-link" href="#the-procstat-interface" aria-label="Heading self-link"></a></h2> <p><code>/proc/stat</code> is a virtual file provided by the kernel&rsquo;s proc filesystem. It contains system-wide statistics aggregated across all CPUs and individual per-CPU lines. The format is non-blocking and updated atomically by the kernel scheduler&rsquo;s tick handler.</p>