User Guide

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Problem: Unexpected Paused Time

You may see unexpected Paused time in the
Timeline
pane even though you did not add any calls to the
__itt_pause()
API or manually paused the analysis target. For example:
This may happen when collecting call stacks with hardware event-based sampling (EBS).

Cause

In the above example, the application called
__itt_pause()
at about the 22 sec mark. But the other, smaller pauses were inserted by the
VTune
Profiler
, which temporarily pauses profiling when data generation rate exceeds data spill rate and it is about to lose data. The data is flushed and then the collection resumes. In the paused regions, your application is not executing: the
VTune
Profiler
lets the application exhaust its current quanta and then prevents it from being scheduled on the CPU until all the data has been saved to a file.

Solution

You can ignore this injected paused time. For example, in the
Summary
information below, you can see that Paused Time is part of the Elapsed Time, but is not included in CPU Time.

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