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diff --git a/static/freebsd/man4/ptnet.4 3.html b/static/freebsd/man4/ptnet.4 3.html new file mode 100644 index 00000000..52c179f1 --- /dev/null +++ b/static/freebsd/man4/ptnet.4 3.html @@ -0,0 +1,98 @@ +<table class="head"> + <tr> + <td class="head-ltitle">PTNET(4)</td> + <td class="head-vol">Device Drivers Manual</td> + <td class="head-rtitle">PTNET(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">ptnet</code> — <span class="Nd">Ethernet + driver for passed-through netmap ports</span></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1> +<p class="Pp">This network driver is included in <a class="Xr">netmap(4)</a>, + and it can be compiled into the kernel by adding the following line in your + kernel configuration file:</p> +<div class="Bd Pp Bd-indent"><code class="Cd">device netmap</code></div> +</section> +<section class="Sh"> +<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> +<p class="Pp">The <code class="Nm">ptnet</code> device driver provides direct + access to host netmap ports, from within a Virtual Machine (VM). + Applications running inside the VM can access the TX/RX rings and buffers of + a netmap port that the hypervisor has passed-through to the VM. Hypervisor + support for <code class="Nm">ptnet</code> is currently available for + QEMU/KVM. Any <a class="Xr">netmap(4)</a> port can be passed-through, + including physical NICs, <a class="Xr">vale(4)</a> ports, netmap pipes, + etc.</p> +<p class="Pp">The main use-case for netmap passthrough is Network Function + Virtualization (NFV), where middlebox applications running within VMs may + want to process very high packet rates (e.g., 1-10 millions packets per + second or more). Note, however, that those applications must use the device + in netmap mode in order to achieve such rates. In addition to the general + advantages of netmap, the improved performance of + <code class="Nm">ptnet</code> when compared to hypervisor device emulation + or paravirtualization (e.g., <a class="Xr">vtnet(4)</a>, + <a class="Xr">vmx(4)</a>) comes from the hypervisor being completely + bypassed in the data-path. For example, when using + <a class="Xr">vtnet(4)</a> the VM has to convert each + <a class="Xr">mbuf(9)</a> to a VirtIO-specific packet representation and + publish that to a VirtIO queue; on the hypervisor side, the packet is + extracted from the VirtIO queue and converted to a hypervisor-specific + packet representation. The overhead of format conversions (and packet + copies, in same cases) is not incured by <code class="Nm">ptnet</code> in + netmap mode, because mbufs are not used at all, and the packet format is the + one defined by netmap (e.g., <var class="Ar">struct netmap_slot</var>) along + the whole data-path. No format conversions or copies happen.</p> +<p class="Pp">It is also possible to use a <code class="Nm">ptnet</code> device + like a regular network interface, which interacts with the + <span class="Ux">FreeBSD</span> network stack (i.e., not in netmap mode). + However, in that case it is necessary to pay the cost of data copies between + mbufs and netmap buffers, which generally results in lower TCP/UDP + performance than <a class="Xr">vtnet(4)</a> or other paravirtualized network + devices. If the passed-through netmap port supports the VirtIO network + header, <code class="Nm">ptnet</code> is able to use it, and support TCP/UDP + checksum offload (for both transmit and receive), TCP segmentation offload + (TSO) and TCP large receive offload (LRO). Currently, + <a class="Xr">vale(4)</a> ports support the header. Note that the VirtIO + network header is generally not used in NFV use-cases, because middleboxes + are not endpoints of TCP/UDP connections.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="TUNABLES"><a class="permalink" href="#TUNABLES">TUNABLES</a></h1> +<p class="Pp">Tunables can be set at the <a class="Xr">loader(8)</a> prompt + before booting the kernel or stored in <a class="Xr">loader.conf(5)</a>.</p> +<dl class="Bl-tag"> + <dt id="dev.netmap.ptnet_vnet_hdr"><var class="Va">dev.netmap.ptnet_vnet_hdr</var></dt> + <dd>This tunable enables (1) or disables (0) the VirtIO network header. If + enabled, <code class="Nm">ptnet</code> uses the same header used by + <a class="Xr">vtnet(4)</a> to exchange offload metadata with the + hypervisor. If disabled, no header is prepended to transmitted and + received packets. The metadata is necessary to support TCP/UDP checksum + offloads, TSO, and LRO. The default value is 1.</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">netintro(4)</a>, <a class="Xr">netmap(4)</a>, + <a class="Xr">vale(4)</a>, <a class="Xr">virtio(4)</a>, + <a class="Xr">vmx(4)</a>, <a class="Xr">ifconfig(8)</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">ptnet</code> driver was written by + <span class="An">Vincenzo Maffione</span> + <<a class="Mt" href="mailto:vmaffione@FreeBSD.org">vmaffione@FreeBSD.org</a>>. + It first appeared in <span class="Ux">FreeBSD 12.0</span>.</p> +</section> +</div> +<table class="foot"> + <tr> + <td class="foot-date">December 11, 2018</td> + <td class="foot-os">FreeBSD 15.0</td> + </tr> +</table> |