Posts Tagged ‘AMD IOMMU’

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Quick-Take: VMworld 2009 Wrap-Up

September 8, 2009

VMworld 2009 in San Franciso started off with a crash and a fist fight, but ended without further incident. If you’re looking for what happened, it would be hard to beat Duncan Epping’s link-summary of the San Francisco VMworld 2009 at Yellow-Bricks, so we won’t even try. Likewise, Chad Sakacc has some great EMC view point on his Virtualgeek blog, and – fresh from his new book releaseScott Lowe has some great detail about the VMworld keynotes, events and sessions he attended.

There is a great no-spin commentary on VMworld’s “softer underbelly” on Jon William Toigo’s Drunken Data blog – especially the post about Xsigo’s participation in VMworld 2009. Also, Brian Madden has a great wrap-up video of of interviews from the VMworld floor including VMware’s Client Virtualization Platform (CVP) and the software implementation of Teradici’s PC-over-IP.

AMD’s IOMMU was on display using a test mule with two 12-core 6100 processors and a SR5690 chipset. The targets were a FirePro graphics card and a Solarflare 10GE NIC. For IOMMU-based virtualization to have broad appeal, hardware device segmentation must be supported in a manner compatible with vMotion (live migration.) No segmentation was hinted at in AMD’s demo (for FirePro), but the fact that vSphere+IOMMU+Magny-Cours equated to enough stability to be openly demonstrating the technology says a lot about the maturity of AMD’s upcoming chips and chipsets. On the other hand, Solarflare’s demonstration previewed – in 10GE – what could be possible in a future version of IOV for GPU’s:

“The flexible vNIC demonstration will highlight the Solarstorm server adapter’s scalable, virtualized architecture, supporting 100s of virtual machines and 1000s of vNICs. The Solarstorm vNIC architecture provides flexible mapping of vNICs, so that each guest OS can have its own vNIC, as well as traffic management, enabling prioritization and isolation of IP flows between vNICs.”

– Solarflare Press Release

SOLORI’s Take: The controversy surrounding VMware’s “focus” on the VMware “sphere” of products was a non-starter. The name VMworld does not stand for “Virtualization World” – it stands for “VMware World” and denying competitor’s “marketing access” to that venue seems like a reasonable restriction. While it may seem like a strong-arm tactic to some, insisting that vendors/partners are there “for VMworld only” – and hence restricting cross-marketing efforts in and around the venue – makes it more difficult for direct competitors to play the “NASCAR-style marketing” (as Toigo calls it) game.

VMworld is a showcase for technologies driving the virtualization eco-system as seen from VMware’s perspective. While there are a growing number of competitors for virtualization mind-share, VMware’s pace and vision – to date – has been driven by careful observation of use-case more so than innovation for innovation’s sake. It is this attention to business need that has made VMware successful and what defines VMworld’s focus – and it is in that light that VMworld 2009 looks like a great success.

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AMD and Intel I/O Virtualization

April 26, 2009

Virtualization now reaches an I/O barrier where consolidated applications must vie for increasingly more limited I/O resources. Early virtualization techniques – both software and hardware assisted – concentrated on process isolation and gross context switching to accelerate the “bulk” of the virtualization process: running multiple virtual machines without significant processing degradation.

As consolidation potentials are greatly enhanced by new processors with many more execution contexts (threads and cores) the limitations imposed on I/O – software translation and emulation of device communication – begin to degrade performance. This degradation further limits consolidation, especially where significant network traffic (over 3Gbps of non-storage VM traffic per virtual server) or specialized device access comes into play.

I/O Virtualization – The Next Step-Up

Intrinsic to AMD-V in revision “F” Opterons and newer AM2 processors is I/O virtualization enabling hardware assisted memory management in the form of a Graphics Aperture Remapping Table (GART) and the Device Exclusion Vector (DEV). These two facilities provide address translation of I/O device access to a limited range of the system physical address space and provide limited I/O device classification and memory protection.

Combined with specialized software GART and DEV provided primitive I/O virtualization but were limited to the confines of the memory map. Direct interaction with devices and virtualization of device contexts in hardware are efficiently possible in this approach as VMs need to rely on hypervisor control of device access. AMD defined its I/O virtualization strategy as AMD IOMMU in 2006 (now AMD-Vi) and has continued to improve it through 2009.

With the release of new motherboard chipsets (AMD SR5690) in 2009, significant performance gains in I/O will be brought to the platform with end-to-end I/O virtualization. Motherboard refreshes based on the SR5690 should enable Shanghai and Istanbul processors to take advantage of the full AMD IOMMU specification (now AMD-Vi).

Similarly, Intel’s VT-d approach combines chipset and CPU features to solve the problem in much the same way. Due to the architectural separation of memory controller from CPU, this meant earlier processors not only carry the additional instruction enhancements but they must also be coupled to northbridge chipsets that contained support. This feature was initially available in the Intel Q35 desktop chipset in Q3/2007. Read the rest of this entry ?