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Department of Computer Science and Technology

Software Prefetching for Indirect Memory Accesses

23 February 2017

I’ve always considered software prefetching to be something of a black art. There have been times in the past when I’ve looked at my code, noticed a load is causing problems and tried inserting one or more software prefetches to alleviate the issue. Mostly this hasn’t worked, although I’ve never been sure why. In fact, even when it has worked I haven’t been totally sure why it has, usually because it’s involved a lot of trial and error in trying out different options before I hit on improved performance.

Now it turns out that most of the time I was probably trying to prefetch the wrong things. Trying to prefetch linked data structures, which are those that involve pointer chasing (like a linked list),...

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Hardware Graph Prefetchers

3 June 2016

This week sees the publication of two papers from my research group at ICS 2016 and so, in this post, I’d like to look a little more into one of these schemes: the graph prefetcher that my student, Sam, has developed.

Graph workloads are important in a number of domains, and becoming increasingly so. You only have to look at the numerous social media applications to see examples of graph-based data (e.g. in a network of people, each person is a vertex and the edges represent links to friends). But graph representations are also significant in less publicly-visible application areas, such as those in scientific computing or “big data” analytics. However, efficient processing of graph workloads is often...

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