Other Environment Variables

Print out debugging information when an MPI program starts running.

Syntax

I_MPI_DEBUG=<level>[,<flags>]

Arguments

`<level>`	Indicate level of debug information provided
`0`	Output no debugging information. This is the default value.
`1`	Output verbose error diagnostics.
`2`	Confirm which `I_MPI_FABRICS` was used and which Intel® MPI Library configuration was used.
`3`	Output effective MPI rank, `pid` and node mapping table.
`4`	Output process pinning information.
`5`	Output environment variables specific to Intel MPI Library.
`6`	Output collective operation algorithms settings.
`> 6`	Add extra levels of debug information.

`<flags>`	Comma-separated list of debug flags
`pid`	Show process id for each debug message.
`tid`	Show thread id for each debug message for multithreaded library.
`time`	Show time for each debug message.
`datetime`	Show time and date for each debug message.
`host`	Show host name for each debug message.
`level`	Show level for each debug message.
`scope`	Show scope for each debug message.
`line`	Show source line number for each debug message.
`file`	Show source file name for each debug message.
`nofunc`	Do not show routine name.
`norank`	Do not show rank.
`flock`	Synchronize debug output from different process or threads.
`nobuf`	Do not use buffered I/O for debug output.

Description

Set this environment variable to print debugging information about the application.

Note

Set the same <level> value for all ranks.

You can specify the output file name for debug information by setting the I_MPI_DEBUG_OUTPUT environment variable.

Each printed line has the following format:

[<identifier>] <message>

where:

<identifier> is the MPI process rank, by default. If you add the '+' sign in front of the <level> number, the <identifier> assumes the following format: rank#pid@hostname. Here, rank is the MPI process rank, pid is the UNIX* process ID, and hostname is the host name. If you add the '-' sign, <identifier> is not printed at all.
<message> contains the debugging output.

The following examples demonstrate possible command lines with the corresponding output:

$ mpirun -n 1 -env I_MPI_DEBUG=2 ./a.out
...
[0] MPI startup(): shared memory data transfer mode

The following commands are equal and produce the same output:

$ mpirun -n 1 -env I_MPI_DEBUG=+2 ./a.out
$ mpirun -n 1 -env I_MPI_DEBUG=2,pid,host ./a.out
...
[0#1986@mpicluster001] MPI startup(): shared memory data transfer mode

Note

Compiling with the -g option adds a considerable amount of printed debug information.

I_MPI_DEBUG_OUTPUT

Set output file name for debug information.

Syntax

I_MPI_DEBUG_OUTPUT=<arg>

Arguments

`<arg>`	String value
`stdout`	Output to `stdout`. This is the default value.
`stderr`	Output to `stderr`.
`<file_name>`	Specify the output file name for debug information (the maximum file name length is 256 symbols).

Description

Set this environment variable if you want to split output of debug information from the output produced by an application. If you use format like %r, %p or %h, rank, process ID or host name is added to the file name accordingly.

I_MPI_OUTPUT_CHUNK_SIZE

Set the size of the stdout/stderr output buffer.

Syntax

I_MPI_OUTPUT_CHUNK_SIZE=<size>

Arguments

`<size>`	Define output chunk size in kilobytes
`<n>` `> 0`	The default chunk size value is 1 KB

Description

Set this environment variable to increase the size of the buffer used to intercept the standard output and standard error streams from the processes. If the <size> value is not greater than zero, the environment variable setting is ignored and a warning message is displayed.

Use this setting for applications that create a significant amount of output from different processes. With the -ordered-output option of mpiexec.hydra, this setting helps to prevent the output from garbling.

Note

Set the I_MPI_OUTPUT_CHUNK_SIZE environment variable in the shell environment before executing the mpiexec.hydra/mpirun command. Do not use the -genv or -env options for setting the <size> value. Those options are used only for passing environment variables to the MPI process environment.

I_MPI_REMOVED_VAR_WARNING

Print out a warning if a removed environment variable is set.

Syntax

I_MPI_REMOVED_VAR_WARNING=<arg>

Arguments

`<arg>`	Binary indicator
`enable \| yes \| on \| 1`	Print out the warning. This is the default value
`disable \| no \| off \| 0`	Do not print the warning

Description

Use this environment variable to print out a warning if a removed environment variable is set. Warnings are printed regardless of whether I_MPI_DEBUG is set.

I_MPI_LIBRARY_KIND

Specify the Intel® MPI Library configuration.

Syntax

I_MPI_LIBRARY_KIND=<value>

Arguments

`<value>`	Binary indicator
release	Multi-threaded optimized library (with the global lock). This is the default value
debug	Multi-threaded debug library (with the global lock)
release_mt	Multi-threaded optimized library (with per-object lock for the thread-split model)
debug_mt	Multi-threaded debug library (with per-object lock for the thread-split model)

Description

Use this variable to set an argument for the mpivars.[c]sh script. This script establishes the Intel® MPI Library environment and enables you to specify the appropriate library configuration. To ensure that the desired configuration is set, check the LD_LIBRARY_PATH variable.

Example

$ export I_MPI_LIBRARY_KIND=debug

Setting this variable is equivalent to passing an argument directly to the mpivars.[c]sh script:

Example

$ . <installdir>/intel64/bin/mpivars.sh release