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# Difference between revisions of "Vampirtrace"

The VampirTrace library allows MPI communication events of a parallel program to be recorded as a trace file. Additionally, certain program-specific events can also be included. To record MPI communication events, simply relink the program with the VampirTrace library. A new compilation of the program source code is only necessary if program-specific events should be added.

## Introduction

Tracing with Vampir in three steps:

1. Compiling with the vampirtrace wrappercompiler
2. Running the application
3. Analysing the trace files using vampir or vampir-server

For detailed usage of Vampirtrace see the user manual which can either be found on your local machine or in the internet.

## Usage

### Compiling with the vampirtrace wrappercompiler

First you should load the needed software module:

Now you can compile your application using the wrapper compilers vtcc, vtf90, ... as described in the user VampirTrace manual.

Note: When using vampirtrace in combination with MPI you will need at least to specify the name of your mpi compiler to VampirTrace
vtf90 -vt:f90 mpif90
vtcc  -vt:cc  mpicc

### Generating the trace files

Run your applicatin as usual. This will generate the needed tracefiles

#### BW-Grid special:

On the BW-Grid you first have to login to a node as some libs are not accessible from the frontend

qsub -I -l walltime=1:00:00

### Viewing traces with vampir or Vampir-Server

There are two GUIs available to view your trace files: Vampir and Vampir-Server. For both you will need read access to all generated output files (*.def.z, *.events.z, *.otf).

Note: Because Vampir and Vampir-Server are GUIs don't forget to use X-forwarding when you login via ssh.

#### Vampir

Vampir is the sequential version of the graphical trace file analyzing software. It is capable of analyzing smaller trace files and should not be used for files which have 100MB or more.

#### Vampir-Server

Vampir-Server is the parallel version of the graphical trace file analyzing software. It can be found on the SX-8 frontend (a1.hww.de). The tool consists of a client and a server. The server itself is a parallel MPI Program.

First load the necessary software module

Now start the server and afterwards the client

vngd &

Remember the port number which will be displays as you will need it later on. Then start the graphical client

vng

The last step is to connect the client to the server using the port number offered you from the server. This is done under

file $\rightarrow$ Connect to Server ...

Then you can open your traces via

file $\rightarrow$ Open Tracefile  ...

Select the desired *.otf file

## Trouble shooting

If the program crashes unexpectedly it is possible that there is not enough space on the node local /tmp. A solution is to use a workspace in combination with the VT_PROFM_LDIR variable

In some cases problems concerning library issues occure. In this case it could help

export LD_LIBRARY_PATH=/opt/NECcomp/compiler100/ia64/lib