Developer Guide

Intel oneAPI FPGA Handbook

ID 785441
Date 2/07/2024
Public

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Reduce Area Resource Use While Profiling

Due to various performance counters being added to the pipeline, introducing profiling into your design can result in a large amount of area resource use. This may be inconvenient for particularly large designs as adding profiling performance counters might result in no fit errors.

To reduce the amount of area resources that profiling takes up, you can choose to profile with shared performance counters. This profiling mode allows counters to be shared by various signals over multiple design runs to reduce the number of performance counters added to the design. During run time, the Profiler Runtime Wrapper runs the host application four times, where, for each run, the counters count a different signal.

NOTE:

You must invoke the Profiler Runtime Wrapper only once.

To turn on the shared performance counters profiling mode, perform these steps:

  1. Include the -Xsprofile-shared-counters flag along with the -Xsprofile flag during your compile.
  2. Include the -shared-counters flag when running your design with the Profiler Runtime Wrapper.

    The -shared-counters flag tells the profiled to run your design multiple times to collect the profiling data from everywhere requested. If you do not include the -shared-counters flag, your design is run only once, which provides a limited set of profiler data (no data for everything after the first shared signal).

CAUTION:

The shared performance counters profiling mode works well only for kernels and designs that are deterministic. Because the host application and design are run multiple times to collect all of the data, non-deterministic designs result in shared data that is difficult to combine, and it may be difficult to determine where design problems occur temporally.