Embedded Systems Design Europe - February 2008 - (Page 31)

feature ers visualize all the system’s cores and choose any combination to debug, each optionally in its own window. At the same time, the tool provides controls for synchronized running and halting of the debugged cores. RUN-MODE MULTICORE DEBUGGING Run-mode debugging is also useful for SMP systems, as the cores are never stopped. Rather, the debugger controls application threads using a communications channel (usually Ethernet) between the host PC and a target-resident debug agent. The SMP operating system typically provides an integrated debug agent (and the associated communications device drivers) that’s operatingsystem–aware and provides ﬂexible options for interrogating the system. For example, one operating system comes with a powerful debug agent that communicates with the debugger, providing the ability to debug any combination of user threads on any core. The user can set specialized breakpoints that enable user-deﬁned groups of threads to be halted when another thread hits the breakpoint. Some classes of bugs require this ﬁnegrained level of control. By collecting a system’s execution history and making it available for playback within debugging tools, even the most difﬁcult multicore bugs become easy to ﬁnd and ﬁx. If you’re new to SMP, choosing a processor with onchip trace capabilities may be desirable. Multicore trace capability is just starting to arrive on multicore processors. A major technical challenge that has kept this hardware feature from becoming a reality involves ﬁnding a way to keep up with trace data emitted simultaneously from multiple cores. An emerging solution is high-speed serial trace (HSST). HSST replaces the current generation of parallel trace ports by taking advantage of highspeed serial bus technology, which enables higher data throughput with a lower pin count. HSST has been proposed to the Nexus standards committee. In addition, ARM has adopted HSST as part of its CoreSight trace solution. SMP is a promising technology for improved performance in an attractive cost and power footprint. However, SMP is not a panacea. The application must have the potential for concurrency, and designers may need to manually refactor software to unlock this concurrency. Furthermore, SMP systems are more difﬁcult to manage and debug than unicore designs. This in turn may require switching operating systems and tooling to acquire the load balancing and multicore debugging capabilities that go hand in hand with SMP. David Kleidermacher (davek@ghs.com) is chief technology ofﬁcer at Green Hills Software where he has been designing compilers, software development environments, and real-time operating systems for the past 16 years. www.embedded.com/europe | embedded systems design europe | JANUARY – FEBRUARY 2008 31 028-029-030-031_ESDE.indd 31 8/02/08 11:11:12 http://www.lauterbach.co.uk http://www.lauterbach.de http://www.lauterbach.it http://www.lauterbach.com http://www.lauterbach.cn http://www.lauterbach.co.jp http://www.lauterbach.com http://www.embedded.com/europe

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Embedded Systems Design Europe - February 2008 Contents ARTEMIS and ENIAC Get Parlimentary Approval Product Teardown Videos Come On Screen Esterel and Abslnt Integrate Products Microsoft Opens Windows to Networked Embedded Applications Trango Embeds Virtualization Tool in Cavium's Multicore CPUs MindTree - ADI Develop Security DVR Platform NXP Extends Deal with ARM to Cover MCUs Automotive and Embedded to Dominate DATE 08 ZigBee Spec Gets Smart On Energy Updated Card Spec Provides for Power-On Boot The Basics of Embedded Multitasking On a PIC Cover Feature: The Art of FPGA Construction Is Symmetric Multiprocessing For You? Accelerating MATLAB Using MEX-Files ARM Provides the Microcontroller Solution Embedded World Advertising Contracts

Embedded Systems Design Europe - February 2008

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