Vampir vampir visualization and Analysis of mpi resources

VAMPIR

VAMPIR

• Visualization and Analysis of MPI Resources

• Commercial tool from PALLAS GmbH

• VAMPIRtrace - MPI profiling library

• VAMPIR - trace visualization tool

VAMPIRtrace

• Separate Installation and User’s Guide for each supported platform

• Works with MPICH and all vendor MPIs

• Instrumentation done by linking your application with the VAMPIRtrace library

• API for stopping and starting tracing and for inserting user-defined events into the trace file

• Trace files generated by MPI processes are automatically collected and merged into a single trace file

VAMPIRtrace API

• Used to start and stop tracing and to define application-specific activities

• Error to call any VAMPIRtrace API routines before MPI_Init or after MPI_Finalize

• To disable trace collection for the local process:

• void VT_traceoff(void)
• SUBROUTINE VTTRACEOFF()

• To re-enable trace collection for the local process:

• void VT_traceon(void)
• SUBROUTINE VTTRACEON()

VAMPIRtrace API (cont.)

• User-defined activities

• Process states with start and stop times
• Activitiy class can contain activities with different symbolic names
• Start and stop routines identify activity by an integer code that is attached to the class/symbol pair by first calling a definition routine
• Activity definitions are process local, but integer codes must be assigned in a globally consistent manner.

VAMPIRtrace Configuration File

• Logfile-name

• Name for logfile to contain merged trace file

• Logfile-rank

• Rank of process that will write logfile

• Internal-msgs [on|off]

• Specifies whether communications internal to the MPI library should be traced

Configuration file (cont.)

• Activity [on|off]

• Defines a filter for matched activity classes

• Symbol [on|off]

• Defines a filter for matched symbol names

• Filter directives are evaluated in order.

Filtering Example

Default Configuration

Limiting VAMPIRtrace Logfile Size

• Limit number of events to be logged by scaling down application input files, iteration count, number of processes, etc.

• Enable trace data collection for just a subset of the application’s runtime.

• Use the filtering mechanism to limit the set of logged events.

Managing VAMPIRtrace API Calls

• Need both instrumented and uninstrumented versions

• Dummy API library libVTnull.a

• Maps API calls to empty subroutines
• Slight overhead

• Use C preprocessor (or equivalent tool for Fortran) to guard calls to the VAMPIRtrace API using #ifdef directives

VAMPIR

• Highly configurable trace visualization tool

• Originally developed by Forschungszentrum Julich GmbH under name PARvis

• Available for all major workstations and some SMPs and MPPs

• Requires graphical display running X11R5 or later

VAMPIR Displays

• Process State Display

• Statistics Display

• Timeline Display

• Communications Statistics

• Configured by using

• Pull-down menus
• Configuration file