User Guide

Contents

threading
Command Line Analysis

Threading analysis helps identify the cause of ineffective processor utilization and shows where your application is not parallel. One of the most common problems is threads waiting too long on synchronization objects (locks). Performance suffers when waits occur while cores are under-utilized.
Threading analysis combines and replaces the Concurrency and Locks and Waits analysis types available in previous versions of
Intel® VTune™
Profiler
.
Threading analysis uses user-mode sampling and tracing collection. With this analysis you can estimate the impact each synchronization object has on the application and understand how long the application had to wait on each synchronization object, or in blocking APIs, such as sleep and blocking I/O.
There are two groups of synchronization objects supported by the
Intel® VTune™
Profiler
:
  • objects usually used for synchronization between threads, such as Mutex or Semaphore
  • objects associated with waits on I/O operations, such as Stream

Syntax

vtune
-collect threading [-knob <
knobName=knobValue
>] [--] <
target
>
For the most current information on available knobs (configuration options) for the Threading analysis, enter:
vtune
-help collect threading
Example
This example shows how to run the Threading analysis on a Linux*
myApplication
application:
vtune -collect threading -- /home/test/myApplication

What's Next

When the data collection is complete, do one of the following to view the result:

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