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Diffstat (limited to 'static/freebsd/man4/kvmclock.4 3.html')
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diff --git a/static/freebsd/man4/kvmclock.4 3.html b/static/freebsd/man4/kvmclock.4 3.html deleted file mode 100644 index ce4cc343..00000000 --- a/static/freebsd/man4/kvmclock.4 3.html +++ /dev/null @@ -1,76 +0,0 @@ -<table class="head"> - <tr> - <td class="head-ltitle">KVMCLOCK(4)</td> - <td class="head-vol">Device Drivers Manual</td> - <td class="head-rtitle">KVMCLOCK(4)</td> - </tr> -</table> -<div class="manual-text"> -<section class="Sh"> -<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> -<p class="Pp"><code class="Nm">kvmclock</code> — - <span class="Nd">Para-virtualized clock driver for x86 KVM guests</span></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> -<p class="Pp">To compile this driver into the kernel, place the following line - in your kernel configuration file:</p> -<div class="Bd Pp Bd-indent"><code class="Cd">device kvm_clock</code></div> -</section> -<section class="Sh"> -<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> -<p class="Pp">This driver reads time-keeping information from the - para-virtualized clock device provided by the KVM hypervisor on Linux hosts. - The <code class="Nm">kvmclock</code> driver is only implemented on i386 and - amd64 platforms. It acts as a <a class="Xr">timecounters(4)</a> device and - is preferred over the Time Stamp Counter (TSC) when available. The driver - exports timekeeping information via <span class="Pa">/dev/pvclock</span>, - enabling the implementation of <a class="Xr">clock_gettime(2)</a> and - related functions without entering the kernel.</p> -<p class="Pp">The <code class="Nm">kvmclock</code> driver works by accessing a - per-vCPU timekeeping structure maintained by the hypervisor. It uses a - combination of TSC readings and information from the shared structure to - produce a high-resolution timecounter which is invariant under hypervisor - events such as vCPU migration and live VM migration.</p> -</section> -<section class="Sh"> -<h1 class="Sh" id="SYSCTL_VARIABLES"><a class="permalink" href="#SYSCTL_VARIABLES">SYSCTL - VARIABLES</a></h1> -<p class="Pp">The following variables are available as both - <a class="Xr">sysctl(8)</a> variables and <a class="Xr">loader(8)</a> - tunables:</p> -<dl class="Bl-tag"> - <dt id="dev.kvmclock.0.vdso_enable_without_rdtscp"><var class="Va">dev.kvmclock.0.vdso_enable_without_rdtscp</var></dt> - <dd>By default, timekeeping information is exported to userspace only when the - (virtual) CPU announces support for the “rdtscp” - instruction. Setting this sysctl to 1 overrides this behavior, allowing - timekeeping information to be exported even in the absence of - “rdtscp” support. However, this breaks compatibility with - copies of <span class="Pa">/lib/libc.so.7</span> released prior to - <span class="Ux">FreeBSD 14.0</span>, and statically linked binaries which - embed a copy of the system C library. Thus, this sysctl value should not - be changed if the system may execute binaries older than - <span class="Ux">FreeBSD 14.0</span>.</dd> - <dt id="dev.kvmclock.0.vdso_force_unstable"><var class="Va">dev.kvmclock.0.vdso_force_unstable</var></dt> - <dd>Mark the timecounter as unstable for userspace consumers. This is mostly - useful for debugging the driver and userspace timekeeping code, and - generally should not be touched.</dd> -</dl> -</section> -<section class="Sh"> -<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE - ALSO</a></h1> -<p class="Pp"><a class="Xr">timecounters(4)</a></p> -</section> -<section class="Sh"> -<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1> -<p class="Pp">The <code class="Nm">kvmclock</code> driver first appeared in - <span class="Ux">FreeBSD 13.1</span>.</p> -</section> -</div> -<table class="foot"> - <tr> - <td class="foot-date">February 1, 2023</td> - <td class="foot-os">FreeBSD 15.0</td> - </tr> -</table> |