Design

The following conditions have to be met by the application:

  • The application handles startup and termination of all processes itself. Both startup with a fixed number of processes and dynamic spawning of processes is supported, but spawning processes is an expensive operation and should not be done too frequently.

  • For a reliable startup, the application has to gather a short string from every process in one place to bootstrap the TCP/IP communication in Intel® Trace Collector. Alternatively one process is started first and its string is passed to the others. In this case you can assume that the string is always the same for each program run, but this is less reliable because the string encodes a dynamically chosen port which may change.

  • Map the hostname to an IP address that all processes can connect to.

Note

This is not the case if /etc/hosts lists the hostname as alias for 127.0.0.1 and processes are started on different hosts. As a workaround for that case the hostname is sent to other processes, which then requires a working name lookup on their host systems.

Intel® Trace Collector for distributed applications consists of a special library (libVTcs) that is linked into the application's processes and the VTserver executable, which connects to all processes and coordinates the trace file writing. Linking with libVTcs is required to keep the overhead of logging events as small as possible, while VTserver can be run easily in a different process.

Alternatively, the functionality of the VTserver can be accomplished with another API call by one of the processes.

Per informazioni complete sulle ottimizzazioni del compilatore, consultare l'Avviso sull'ottimizzazione