Intel qpi what is

This is what is stated in my answer, QPI connects nowadays to other CPUs and that's only possible in the multi-socket case. That is there is just a local memory for A which is non-local for B and vice-versa, and no memory which is non-local to both. The QPI links are generally between sockets, and are probably best through of as connecting the uncore components of separate sockets.

In fact, discussing what QPI is for single socket systems is fraught with confusion - since you can argue that such systems don't really have QPI links per say although some QPI concepts may be internally used in some of the internal interconnects.

So QPI is primarily designed to be an inter-socket interconnect originally, an inter-CPU connection , and one of the primary duties of this interconnect is to satisfy memory access. Show 6 more comments. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete?

Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta. Now live: A fully responsive profile. Linked 2. Related Hot Network Questions. Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. The diagram below shows a 4-way Xeon system with two IOH devices. Notice there 2 QPI links between the processors.

It is unclear whether this configuration has any performance advantages over a system with a single QPI link between processors. The diagram below shows an 8-way glueless Xeon system. Glueless means that there are no silicon components connecting the processors. Memory Controller Mbox Two integrated memory controllers.

Mbox interface logic to Scalable Memory Buffer. Each 64 bytes of cache line stored in memory, there are 16 bits available to be used for directory support.

Hemisphere mode Hemisphere mode of operation the processors Caching Agent 1 will not access it's Home Agent 2, thereby reducing memory latencies. Intel Nehalem based systems with QPI The first Nehalem architecture processor release was the Core i7 for single socket desktop systems in November Xeon and E7 Series The 4-way Nehalem architecture which might be a Dell R scheduled for release in late , actual - Q2.