User Guide


Clockticks Vs. Pipeline Slots Based Metrics

Intel® VTune™
provides hardware event-based metrics for the Microarchitecture Exploration analysis measured either as Clockticks or Pipeline Slots. To understand the difference, consider the following example:
Clockticks and Pipeline Slots Metrics
Here the two slots are wasted on each cycle, which is 50% in terms of Pipeline Slots. But in terms of Clockticks, the stall metrics will be 100% since on each cycle there is some stall. Moreover, on each cycle there may be stalls due to different reasons, which means that metrics measured in Clockticks may overlap.
So, metrics measured in Clockticks are less precise compared to the metrics measured in Pipeline Slots since they may overlap and their sum at some level does not necessarily match the parent metric value. But such metrics are still useful for identifying the dominant performance bottleneck in the code.

Product and Performance Information


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