There is a high of percentage memory instructions with irregular (variable or random) stride accesses. Improve performance by investigating and handling accordingly.
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A target is an executable version of your serial program that you build. Intel® Advisor provides five tools that you use to prepare your program for Threading or SIMD parallelism. These tools invoke and examine your running program. The table below lists these tools and an overview of the target requirements:
The Survey tool runs and watches your running serial program's target executable. After it analyzes (profiles) your target's execution, it displays the Survey Report window to help you choose possible (candidate) places to add parallelism.
Before you can mark the best parallel opportunities by adding annotations , you need to choose likely places to add parallelism. This section introduces several topics that explain factors you should consider as you closely examine the candidate code regions and their execution.
After the Suitability tool runs your program's target executable to collect data, the Suitability Report window appears. It displays the approximate predicted performance based on its analysis of the annotated parallel sites and tasks.
In this example, analysis is performed for an application that is run in four processes.
Collect survey data for all ranks into the shared ./advi project directory.
$ mpirun -n 4 advixe-cl -project-dir ./advi -collect survey -- <PATH>/mpi-sample/1_mpi_sample_serial
If you need to copy the data to the development system, do so now.
Synchronization is a relatively simple way to eliminate sharing problems, but it must be used very carefully.
The purpose of synchronization is to let tasks run safely in parallel, but it does this by not letting them run in parallel when it would be unsafe. A task that is waiting for a lock is not doing any work at all.
Intel® Cilk™ Plus is supported by the Intel® C++ Compiler, which is part of most Intel® Parallel Studio XE editions). It is also supported by other compilers, such as certain versions of the GNU* gcc compiler with the Intel Cilk Plus branch and other compilers (see http://cilkplus.org/which-license). To use Intel Cilk Plus, you must use one of these compilers so they recognize the Intel Cilk Plus keywords.