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Debugging IBM Cell Broadband Engine Programs
SLURM is an open-source resource manager designed for Linux clusters
of all sizes. It provides three key functions. First it allocates exclusive and/
or non-exclusive access to resources (computer nodes) to users for some
duration of time so they can perform work. Second, it provides a framework
for starting, executing, and monitoring work (typically a parallel job)
on a set of allocated nodes. Finally, it arbitrates conflicting requests for
resources by managing a queue of pending work.
SLURM is not a sophisticated batch system, but it does provide an Applications
Programming Interface (API) for integration with external schedulers
such as the Maui Scheduler. While other resource managers do exist,
SLURM is unique in several respects:
� Its source code is freely available under the GNU General Public
License.
� It is designed to operate in a heterogeneous cluster with up to thousands
of nodes.
� It is portable; written in C with a GNU autoconf configuration engine.
While initially written for Linux, other UNIX-like operating systems
should be easy porting targets. A plugin mechanism exists to support
various interconnects, authentication mechanisms, schedulers, etc.
� SLURM is highly tolerant of system failures, including failure of the node
executing its control functions.
� It is simple enough for the motivated end user to understand its source
and add functionality.
Debugging IBM Cell Broadband
Engine Programs
The IBM Cell Broadband Engine is a heterogeneous computer having a PPE
(PowerPC Processor Element) and eight SPEs (Synergistic Processor Elements).
Despite being a heterogeneous computer, the way you debug Cell
programs is nearly identical to the way you use TotalView to debug programs
running on other architectures. (See Figure 98 on page 139.)
Of course, the way in which programs are loaded and execute mean there
are a few differences. For example, when a context is created on an SPU
(Synergistic Processor Unit), this context is not initialized; instead,
resources are simply allocated. This empty context is visible, but there are
no stack traces or source displays. There is no equivalent to this on other
architectures that TotalView supports. At a later time, the PPU (PowerPC
Processor Unit) will load an SPU image into this context and tell it to run.
In all cases, when you focus on a PPU thread, only the PPU address space is
visible. Similarly, when you focus on an SPU thread, the address space of
that SPU thread is visible.
138 Chapter 7: Setting Up Parallel Debugging Sessions