Intel® Trace Analyzer and Collector

SYNCED-HOST

Syntax

SYNCED-HOST [on|off]

Variable

VT_SYNCED_HOST

Default

off

Description

Use this setting to override whether Intel Trace Collector treats the clock of all processes one the same node as synchronized or not. Whether Intel Trace Collector makes that assumption depends on the selected time source.

Buffer Given to MPI Cannot Be Read or Written

(LOCAL:MEMORY:INACCESSIBLE)

During the check for LOCAL:MEMORY:ILLEGAL_MODIFICATION of a send buffer Intel® Trace Collector will read each byte in the buffer once. This works for contiguous as well as non-contiguous data types. If any byte cannot be read because the memory is inaccessible, a LOCAL:MEMORY:INACCESSIBLE is reported. This is an error because it is only possible to proceed by skipping the entire operation.

Mappings in Comparison Views

It is important to compare only comparable things. When comparing two program runs you can try to compare the time that a process A.P0 spent in a function in run A to the time of another process B.P0 in run B with or without caring for the fact that B.P0 did only half of the work because run B used twice as much processes.

Project Menu

The Project menu enables you to save your working environment. The Intel® Trace Analyzer and Collector does not save your environment automatically. You need to save the environment manually.

Intel® Trace Analyzer

You can perform the following actions from the Project menu:

Comparison

The Comparison feature is available from the Views menu bar only when the Comparison mode is activated. To activate it, select View > Compare.

The Comparison menu contains the following entries that enable you to customize the navigation of the compared charts:

  • Same Time Scaling

  • Synchronize Navigation Keys

  • Synchronize Mouse Zoom

Filtering and Tagging

Tagged cells are emphasized by a small additional frame around the cell in the color of the alphanumerical entry in the cell. A cell is tagged as soon as a single tagged message falls into that cell. Here is an example of tagging MPI_Allreduce function in Collective Operations Profile:

Imbalance Diagram Dialog Box

The Imbalance Diagram enables you to compare the performance between a real trace and an ideal trace.

Use the Imbalance Diagram total mode to see the time spent on calculation, interconnect, and imbalance as well as the time distribution between them. The diagram displays the time distribution in different colors.

Use the Imbalance Diagram breakdown mode to see:

  1. how three most time-consuming functions of the application work

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