Josh Simons
High Performance Computing
Biography
With over 20 years of experience in High Performance Computing, Josh currently leads an effort within VMware's Office of the CTO to bring the full value of virtualization to HPC.
Previously, he was a Distinguished Engineer at Sun Microsystems with broad responsibilities for HPC direction and strategy. He joined Sun in 1996 from Thinking Machines Corporation, a pioneering company in the area of Massively Parallel Processors (MPPs), where he held a variety of technical positions. Josh has worked on developer tools for distributed parallel computing, including language and compiler design, scalable parallel debugger design and development, and MPI. He has also worked in the areas of 3D graphics, image processing, and realtime device control. Josh has an undergraduate degree in Engineering from Harvard College and a Masters in Computer Science from Harvard University. He has served as a member of the OpenMP ARB Board of Directors since 2002 and is currently serving as Chairman of the Board.
Posts by Josh Simons
We’ve just published a third Hadoop performance paper, written by VMware performance expert Jeff Buell, which looks in detail at the relative performance of a bare-metal 32-node Hadoop cluster compared to a range of virtual clusters with up to 128 VMs. The executive summary is that while we saw a 13% performance degradation in a head-to-head comparison of a 32-node physical cluster against a 32-VM virtual cluster (one VM per host) running on the same hardware and running the same tests, virtualized performance can be increased significantly — to the point where virtualized Hadoop actually runs a bit faster than physical — by increasing the number of VMs per host. We’ve seen this effect before with Hadoop...
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The Office of the CTO has been exploring how to best enable application access to RDMA for those applications requiring the ultimate in high bandwidth, low-latency communication, which includes many HPC MPI applications as well as many scale-out databases and BigData approaches. Passthrough mode is the most straightforward way to enable guest-level RDMA. With passthrough (which we call VM DirectPath I/O), a physical PCI device can be made directly visible to the guest operating system running within the virtual machine. We published a research note showing that this approach delivers very good InfiniBand latencies (under 2us) and excellent bandwidths over a wide range of message sizes. There is a downside, however: Punching through the virtual machine abstraction in this way disables several...
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It’s time again to dust off the crystal ball, cast the yarrow sticks, read the tea leaves, and share some thoughts about where the IT world is heading over the next twelve months and beyond. Because my focus at VMware is on High Performance Computing (HPC), I’ll confine my prognostications primarily to the growing area of overlap between mainstream Enterprise Computing and HPC — places where each world can benefit from the other in important ways. Before I start, let’s get one no-brainer prediction out of the way: 2012 will be remembered for Nicira , and not Nibiru . Yes, software-defined networking ( SDN ) will trump planetary collisions and the...
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I met recently with a group of academic CIOs and IT Directors in Denver to talk about how virtualization and private cloud technologies can help lower the barriers to adopting a centralized approach to delivering HPC resources in an academic environment. Of course, the barriers and concerns — losing control of resources, fear of not getting ones “fair share” in a shared facility, being forced into a standardized and sub-optimal software environment, etc. – are relevant outside of academia as well. Because the topic is of broad interest, I’ve published the slides in SlideRocket and added an audio track that explains why virtualization should not be viewed simply as a tax one pays to move into a cloud environment, but rather as an approach...
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I spoke last week at ISC Cloud 2012 in Mannheim, Germany about the performance of HPC applications in the cloud, citing results from several studies. I have summarized the talk below and my PDF slide deck is available here . For full details of ISC Cloud 2012, I recommend the coverage at HPC in the Cloud . I gave my talk to share some specific data about HPC performance in virtual environments, but I first described what new capabilities can be gained by virtualizing an HPC environment. I felt this was necessary because in HPC discussions it is often the case that...
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We just announced a pile of new vSphere features at VMworld 2012 in San Francisco this week so I thought I’d take a few moments to describe several of those capabilities that will be of particular interest to High Performance Computing customers.
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I’m in Fiuggi, Italy this week teaching a four-lecture course on Virtualization and High Peformance Computing as part of the Eighth International Summer School on Advanced Computer Architecture for High Performance and Embedded Systems ( ACACES 2012 ). I have about 70 students in the class, primarily from European countries.
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I gave a talk recently at the HPC Advisory Council Workshop at the International Supercomputing Conference ( ISC ’12) in Hamburg. The main purpose of the presentation, which was titled Ultra-low Latency in the Cloud: How low can we go?, was to share our InfiniBand performance results with the HPC community to begin to address the question of whether cloud computing can be useful for more demanding types of applications than the throughput-oriented technical workloads that are known to run well in a virtualized cloud environment. (The short answer is we believe it can.) Before I presented our performance results, I spent the first part of the talk explaining what I see as an...
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I’ll be speaking this weekend at the HPC Advisory Council European Conference 2012 in Hamburg, just prior to the International Supercomputing Conference ( ISC ’12 ), which runs from June 17-21st. If you will be attending either event and would like to talk about HPC and virtualization, send me an email — “simons” at the obvious place.
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I’ve talked to a lot of customers in the past year who have islands of unvirtualized infrastructure within their organizations. Examples include insurance companies running risk analyses, digital content creation companies rendering movie frames, electronic design companies running simulations of chip designs, life sciences organizations running a variety of genomics and other applications, and government agencies running security-related simulations and other workloads. If your organization runs such workloads and you are interested in hearing how they can be virtualized, consider voting for the following VMworld proposal. Public votes can be cast here (free registration required) and voting closes on June 8th. 1984 A self-service model for supporting engineering, scientific and other technical applications in a vCloud environment As the use...
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