IBM Full-System Simulator for the Cell Broadband Engine Processor

1. What's new in this release?

The update to Version 3.1 fixes several bugs identified in the initial 3.1 release.

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2. How can the IBM Full-System Simulator benefit my development process?

The IBM Full-System Simulator is a software application that emulates the behavior of a system containing one or multiple Cell Broadband Engine™ Processors. Users are able to boot a Linux operating system in the simulator and then, in turn, run applications on the simulated operating system. In addition to running applications, the simulator also supports the loading and running of statically-linked executables and stand-alone tests without an underlying operating system.

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2. How can the IBM® Full-System Simulator benefit my development process?

The IBM Full-System Simulator is a software application that emulates the behavior of a Cell Broadband Engine™ Processor. Users are able to boot a Linux operating system on the model and then, in turn, run applications on the simulated operating system. In addition to running applications, a simulated model also supports the loading and running of statically-linked executables and stand-alone tests.

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3. I’m having trouble running the simulator. Where can I go to get help?

The README file contains troubleshooting tips for common problems encountered in running the simulator. If the problem you have is not described in the README, search the Cell BE Forum to see if anyone else has reported a similar problem and whether a solution has been posted. If not, post a detailed description of your problem, including actual simulator output, the machine type and OS version you are using, and application source code or binaries that could be used to recreate the problem when appropriate.

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4. How does the IBM Full-System Simulator for Cell Broadband Engine Processor fit into the overall SDK for Multicore Acceleration?

The IBM Full-System Simulator for the Cell Broadband Engine Processor is a companion technology to the IBM SDK for Multicore Acceleration. Developers can create applications for systems based on the Cell/B.E. processor using the IBM SDK for Multicore Acceleration, and then run these applications on the IBM Full-System Simulator. The simulator allows developers to test and debug applications when access to hardware environments is difficult or limited. The simulator also provides a more controlled environment for analyzing application errors for performance problems.

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5. What documentation is available for the simulator?

The simulator comes with a User’s Guide, which describes the basic operation of the simulator, including its graphical user interface (GUI) and command syntax, and a Performance Analysis Guide, which describes special features of the simulator that allow users to analyze performance characteristics of applications. Both these documents are available in the doc directory of the installed simulator package (typically /opt/ibm/systemsim-cell/doc).

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6. How can I install new build tools or libraries on the simulator sysroot disk?

The sysroot disk available with the IBM SDK for Multicore Acceleration contains a minimal set of build tools and libraries to keep the size of the image file to minimum. A new topic has been added to the simulator User's Guide that describes how to install additional files or packages to the simulator sysroot disk.

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7. Can I use the simulator to get an accurate estimate of the performance of my application?

Support for performance simulation has been evolving since the IBM Full-System Simulator for the Cell Broadband Engine platform was originally released on alphaWorks. The first version of the simulator provided a cycle-accurate model of SPU instruction execution, which enabled developers to gather detailed performance data about the execution of SPU programs, such as pipeline stalls, operand dependencies, and so forth. Subsequent versions of the simulator have provided performance simulation of memory subsystem functions (in version 2.0) and the PPU execution (in version 2.1). As a result, the simulator now supports performance simulation for nearly all aspects of the Cell Broadband Engine processor operation.

The performance models for all components are disabled by default when the simulator is started, so you must explicitly enable the performance models in order to get meaningful performance results. The performance models add a significant amount of overhead to simulator execution, so you should expect a reduction in simulation speed of 10 times or more, depending on the application, when running simulations with performance models enabled.

The performance models in the simulator are intended to compliment the performance analysis tools and techniques available on actual hardware. However, the performance models of the simulator provide only estimates of actual performance results on hardware, and may differ significantly from hardware results in certain circumstances. We expect that the performance models in the simulator will be helpful in initial performance tuning efforts and for diagnosing performance problems. However, only performance results from hardware should be used when precise performance information is required.

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8. Where can I find general information on Cell Broadband Engine (Cell/B.E.)?

You can find out more about the Cell Broadband Engine at the Cell Broadband Engine resource center.

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