User Guide

Contents

Using
Intel® Inspector
and
Intel® VTune™
Profiler

Intel® Advisor
helps you:
  • Discover where to add parallelism to your program by identifying where your program spends its time. You propose parallel code regions when you annotate the parallel sites and tasks.
  • Predict the performance you might achieve with the proposed parallel code regions.
  • Predict the data sharing problems that could occur in the proposed parallel code regions.
Intel Advisor
does not catch all problems, and it cannot ensure that you have correctly implemented the parallelism. Before deploying your parallel program, you need to test it for Dependencies and verify its performance. To do this, you can use analyzer tools provided in certain editions of the
Intel® Parallel Studio XE
suite.
The thread error analysis provided by
Intel® Inspector
and the
Intel Advisor
Dependencies analysis tool use similar technology. Intel Inspector includes a data race and deadlock detection tool that works on the
parallel
code. It can find more errors because it operates on the parallel code instead of working on the annotated
serial
code analyzed by the Dependencies tool. Intel Inspector also can find problems with memory: memory leaks, references to freed storage, references to uninitialized memory, and so forth. The memory-checking tool works on serial or parallel code.
Similarly, the
Intel Advisor
Survey and Suitability tools provide features found in the
Intel® VTune™
Profiler
. The Survey tool profiles your program to find hotspots and the Suitability tool makes predictions of approximate parallel performance including overhead costs based on the
Intel Advisor
annotations. When you have a working parallel program, you should use
Intel VTune
Profiler
to measure the parallel program gain and core utilization, as well as check whether the parallel framework overhead is acceptable.
Once you have parallel code, you should:
  • Measure the speedup.
  • Make adjustments if locks are causing excessive delays, or if one task runs much longer than others.
Intel VTune
Profiler
has many features to help you find and fix performance problems in your parallel code. It also helps you check:
  • Where are the hotspots now?
  • Am I missing opportunities for more parallelism?
  • Is my program spending a lot of time waiting?
  • How does the performance compare to that of prior versions?
Another technique is to use a debugger to debug a serial version of your parallel program with the parallel constructs in reverse order (see Debugging Parallel Programs).

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804