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Altair FlowTracer User Guide
FlowTracer is a complete system to create, manage, and execute design flows.
Run, Rerun, Stop and Kill Jobs
The act of requesting FlowTracer to bring a particular target up-to-date is sometimes called a Retrace Request or more simply a Retrace.
Rerun Modes
There are several "modes" of running (retracing), having to do with the way jobs are scheduled and the way jobs are executed. The default mode of execution is "SAFE".

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View new features for FlowTracer 2025.1.0.
FlowTracer Overview
An advanced mission critical dependency management platform for developing and executing flows.
FlowTracer Tutorials
Discover FlowTracer functionality with interactive tutorials.
Altair FlowTracer User Guide
FlowTracer is a complete system to create, manage, and execute design flows.
- FlowTracer Roles
  When using FlowTracer in large deployments, three main roles emerge: Administrator, Developer and User. In smaller organizations, a given person may have multiple roles, but the duties of each role still exist.
- Introduction to VOV
  FlowTracer is derived from the system "VOV" originally developed at UC-Berkeley. The word "VOV" is not an acronym, but can be thought of as a contraction of the word "evolve".
- Concepts and Terminology
- Run, Rerun, Stop and Kill Jobs
  The act of requesting FlowTracer to bring a particular target up-to-date is sometimes called a Retrace Request or more simply a Retrace.
  - Run and Rerun
  - Rerun from the Browser
    When visiting a page for a set of nodes, you can start a run using the Run bar. The bar allows you to select priority and flags.
  - Rerun from the GUI
  - Rerun from the Command Line Interface
    From the CLI, you can request FlowTracer to run with the command vsr.
  - Rerun the down-cone of a File (kicking a file)
  - Rerun Modes
    There are several "modes" of running (retracing), having to do with the way jobs are scheduled and the way jobs are executed. The default mode of execution is "SAFE".
  - Priority
    The scheduling priority affects the order in which the jobs are scheduled. The range is 1 to 15.
  - Rerun Failed Jobs
    A job is labeled as FAILED if something has gone wrong during the execution of the job.
  - Job Life Cycle During a Run
  - Avoid Expensive Reruns
    Sometimes a complete run may take too much time, and you may want to find ways to bypass an expensive execution, at least in the short term, in order to focus on a more urgent issue.
  - Check All Files in a Project
    When you request a run, the FlowTracer server checks the timestamp of all primary inputs in the up-cone of the target.
  - Job Queue
    For each run request (which calculates the runtime tracing graph), VOV creates a set to contain all the jobs to be executed to satisfy the request. Then VOV takes all the jobs that are ready to execute and places them into the Job Queue in order of priority.
  - Dequeue and Stop Jobs
    Often we use the verb "stop" in a loose fashion, but in this section it is important to distinguish "dequeue" from "stop". Dequeuing only impacts scheduled jobs and leaves running jobs unaffected, while "stopping" really means killing jobs that are running.
  - Kill Processes using the CLI
    In order to kill a job, you must be on the machine on which the job is running, identify the PID of the job and then send the Kill signal to the PID.
- Find, Remove and Clean Files
- Graphical User Interface
- Browser Interface
  This chapter will cover how you can use your web browser to manage FlowTracer.
- Command Line Interface
  The Altair Accelerator products have a rich set of programs that can be run on the shell command line.
- Create Sets with Selection Rules
- Advanced Information
- Troubleshooting
- Create a FlowTracer Project
- Resource Management
  Altair Accelerator includes a subsystem for managing computing resources. This allows the design team to factor in various constraints regarding hardware and software resources, as well as site policy constraints.
- Rename Nodes
  Renaming of nodes is a task for more advanced users. In most cases, it is simpler to forget all nodes and rebuild the trace from scratch.
- Miscellaneous
- Reports
Altair FlowTracer Administrator Guide
This manual is aimed at the person who will be the administrator for FlowTracer. This person will be responsible for configuring the network resources, setting up the licensing, and establishing security and access rules for the system.
Altair FlowTracer Developer Guide

View All Altair Accelerator Help

Rerun Modes

There are several "modes" of running (retracing), having to do with the way jobs are scheduled and the way jobs are executed. The default mode of execution is "SAFE".

Mode

Description

FAST

This flag affects the execution of the jobs. If the execution is FAST, runtime tracing is disabled for the job, meaning that the dependencies are not recomputed.

AGGRESSIVE

This flag affects the firing of the jobs in the presence of barriers. Normally, a job is ready to fire only if its entire up-cone is VALID. If the "AGGRESSIVE" flag is used, a job will fire if all its immediate inputs are VALID. The situation where the immediate inputs are VALID but the up-cone is not VALID normally arises when you have barriers.

In AGGRESSIVE mode, jobs are fired in parallel above and below the barrier. If the barrier stops the change propagation, all is OK. Otherwise, the jobs below the barrier will have to be re-executed.

The default mode is not AGGRESSIVE, meaning that all jobs above the barrier are executed before the jobs below the barrier.

CROSSBARRIERS

This flag affects the running of jobs in the presence of barriers. Normally, when you run a target, only the jobs below the barriers are run. With the "CROSSBARRIERS" flag, all jobs in the up-cone of the target will be run.

FORCEFAILED

This flag affects the running of FAILED jobs. Normally, FAILED jobs remain FAILED, until the inputs change. With the "FORCEFAILED" flag, the failed nodes in the up-cone of the target are also run.

SKIPCHECK

This flag affects the checking of the primary inputs in the up-cone of the target. Normally, FlowTracer checks the timestamp of all primary inputs, but this could be expensive especially if you are using a slow filesystem such as ClearCase. If you set this flag, the check is skipped.

This flag reduces the reliability of the running. You should use this flag in conjunction with alternative ways to check timestamps, such as vls or vovcheckfiles.

SAFE

This is the name for the default mode, the one in which all flags mentioned above are OFF.