Midgard, a paradigm shift in virtual memory use in data centers

Virtual Memory has always been a pillar for memory isolation, protection, and security in digital platforms. As services host more data in server memory for faster access, the traditional virtual memory technologies that lookup data in server memory and check for protection have emerged as a bottleneck.

Data centers that provide services such as social networks or business analytics spend more than 20% of their processing time in virtual memory and protection checks. This means any gains made in this area can have a massive effect on server efficiency and data security.

Now, EPFL researchers have pioneered an innovative approach to implementing virtual Memory in data centers. They have developed Midgard, a software-modeled prototype demonstrating proof of concept to greatly increase server efficiency. It is an intermediate address space between the virtual and the physical address spaces to mitigate address translation overheads without program-level changes.

Midgard is a technology that can allow for growing memory capacity while continuing to guarantee the security of the data of each user in the cloud services,” explains Professor Babak Falsafi, Founding Director of the Ecocloud Center and one of the paper’s authors.

With Midgard, the all-important data lookups and protection checks are done directly in on-chip memory rather than virtual memory, removing so much of the traditional hierarchy of lookups and translations that it scores a net gain in efficiency, even as more memory is deployed,” he continued.

In the recent tests, the Midgard achieves only 5% higher address translation overhead as compared to traditional TLB hierarchies. But at loads of 256 MB aggregate large cache, it was able to outperform traditional systems in terms of virtual memory overheads.

While the Midgard technology does represent a paradigm shift, it is compatible with existing operating systems such as Windows, MacOS, and Linux. This is the first of several steps needed to demonstrate a fully working system with Midgard. The researchers focused on a proof-of-concept software-modeled prototype of key architectural components.

Future work will address the wide spectrum of topics needed to realize Midgard in real systems, such as compatibility development, packaging strategies, and maintenance plans.


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