Intel's powerful new Xeon Phi co-processor
Operating System
Because the Xeon Phi has full-fledged cores, not just highly optimized special-purpose computing units, it can run its own operating system. Intel leverages this ability to manage the board's resources and simplify software development.
When the host computer boots, the Xeon Phi first appears as a normal PCI device; the processor on the board is inactive. To activate the card, the host system's system management controller helps load an initrd image with a built-in BusyBox into the Xeon Phi's memory.
The Linux kernel used on the Xeon Phi differs only slightly from an ordinary x86 kernel; the necessary adjustments are comparable to those for an ARM image. After the image is transferred, the processor is started, and Linux is booted on the card for the first time. The coprocessor either uses initrd directly as the root filesystem, or it loads a filesystem from the host computer to the memory card, or it uses NFS to retrieve a filesystem.
Data Exchange
The PCIe bus allows the host system to write data to a memory expansion card. Conversely, expansion cards can also write to the memory of the host computer. However, writing directly to the memory of the host system is extremely awkward for an application programmer because this kind of low-level data transfer usually only takes place at the driver level. Intel therefore provides the Symmetric Communications Interface (SCIF), a library that includes an easy-to-use interface for low-level data transfer at the memory level. SCIF is the most efficient way of exchanging data between the host computer and the Xeon Phi card, and it also provides a means for transferring the root file system to the memory of the card.
Networking via Virtio
Intel has implemented additional data exchange options. The most important of these options integrates the card into a network. Intel uses the Virtio framework [5], among other things, for network access. Virtio provides virtual Ethernet interfaces on both the host system and the card's operating system, with the data traveling across the PCIe bus. The Ethernet interfaces operates in typical Linux style. In other words, the virtual Ethernet interface on the host operating system can connect to a physical port on the host computer and the Linux running on the card can join the local network via the virtual network interface (Figure 2).
Following the same principle, Intel has also implemented a virtual serial port and a virtual block device. The virtual serial port is designed to transfer the boot log, debug messages, and other status information to the host computer. The block device is actually intended to provide the Linux swap space on the card, but if you modify the init scripts supplied by Intel appropriately, it also provides a root filesystem and thus basically a fourth option for booting the card.
« Previous 1 2 3 Next »
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Direct Download
Read full article as PDF:
Price $2.95
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Find SysAdmin Jobs
News
-
MNT Seeks Financial Backing for New Seven-Inch Linux Laptop
MNT Pocket Reform is a tiny laptop that is modular, upgradable, recyclable, reusable, and ships with Debian Linux.
-
Ubuntu Flatpak Remix Adds Flatpak Support Preinstalled
If you're looking for a version of Ubuntu that includes Flatpak support out of the box, there's one clear option.
-
Gnome 44 Release Candidate Now Available
The Gnome 44 release candidate has officially arrived and adds a few changes into the mix.
-
Flathub Vying to Become the Standard Linux App Store
If the Flathub team has any say in the matter, their product will become the default tool for installing Linux apps in 2023.
-
Debian 12 to Ship with KDE Plasma 5.27
The Debian development team has shifted to the latest version of KDE for their testing branch.
-
Planet Computers Launches ARM-based Linux Desktop PCs
The firm that originally released a line of mobile keyboards has taken a different direction and has developed a new line of out-of-the-box mini Linux desktop computers.
-
Ubuntu No Longer Shipping with Flatpak
In a move that probably won’t come as a shock to many, Ubuntu and all of its official spins will no longer ship with Flatpak installed.
-
openSUSE Leap 15.5 Beta Now Available
The final version of the Leap 15 series of openSUSE is available for beta testing and offers only new software versions.
-
Linux Kernel 6.2 Released with New Hardware Support
Find out what's new in the most recent release from Linus Torvalds and the Linux kernel team.
-
Kubuntu Focus Team Releases New Mini Desktop
The team behind Kubuntu Focus has released a new NX GEN 2 mini desktop PC powered by Linux.