User Guide

  • 2020.3
  • 07/10/2020
  • Public Content
Contents

Some applications require the capability to trace events with user-defined timestamps and frequencies different from the timestamps and frequencies generated by a CPU, for example, to instrument events that occur on a GPU. For the purpose you can create a clock domain.
To create a clock domain, use the following primitive:
__itt_clock_domain * ITTAPI __itt_clock_domain_create(__itt_get_clock_info_fn fn, void* fn_data)
Parameters of the primitive:
[in]
fn
Pointer to a callback function that retrieves alternative CPU timestamps and frequencies and stores the timestamps and frequencies data in the clock domain structure field __itt_clock_info
[in]
fn_data
Argument of a callback function; can be NULL
Tasks issued from different clock domains are shown on the same timeline by synchronizing a referenced clock domain base timestamp captured at the moment of clock domain creation and a CPU timestamp captured at the same time.
To recalculate clock domain base timestamps and frequencies, if necessary, for example, when a GPU frequency changes, use the following primitive:
__itt_clock_domain_reset()
 

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