Intel® MPI Library Developer Reference for Windows* OS
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.
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 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:
> mpiexec -n 1 -env I_MPI_DEBUG=2 test.exe
...
[0] MPI startup(): shared memory data transfer mode
The following commands are equal and produce the same output:
> mpiexec -n 1 -env I_MPI_DEBUG=+2 test.exe > mpiexec -n 1 -env I_MPI_DEBUG=2,pid,host test.exe ... [0#1986@mpicluster001] MPI startup(): shared memory data transfer mode
Compiling with the /Zi, /ZI or /Z7 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.
Choose the network interface for MPI communication over sockets.
Syntax
I_MPI_NETMASK=<arg>
Arguments
<arg> |
Define the network interface (string parameter) |
<interface_mnemonic> |
Mnemonic of the network interface: ib or eth |
ib |
Select IPoIB* |
eth |
Select Ethernet. This is the default value |
<network_address> |
Network address. The trailing zero bits imply netmask |
<network_address/netmask> |
Network address. The <netmask> value specifies the netmask length |
<list of interfaces> |
A colon separated list of network addresses or interface mnemonics |
Description
Set this environment variable to choose the network interface for MPI communication over sockets in the sock and ssm communication modes. If you specify a list of interfaces, the first available interface on the node will be used for communication.
Examples
Use the following setting to select the IP over InfiniBand* (IPoIB) fabric:
I_MPI_NETMASK=ib
I_MPI_NETMASK=eth
Use the following setting to select a particular network for socket communications. This setting implies the 255.255.0.0 netmask:
I_MPI_NETMASK=192.169.0.0
Use the following setting to select a particular network for socket communications with netmask set explicitly:
I_MPI_NETMASK=192.169.0.0/24
Use the following setting to select the specified network interfaces for socket communications:
I_MPI_NETMASK=192.169.0.5/24:ib0:192.169.0.0
If the library cannot find any suitable interface by the given value of I_MPI_NETMASK, the value will be used as a substring to search in the network adapter's description field. And if the substring is found in the description, this network interface will be used for socket communications. For example, if I_MPI_NETMASK=myri and the description field contains something like Myri-10G adapter, this interface will be chosen.
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.
Specify the Intel® MPI Library configuration.
Syntax
I_MPI_LIBRARY_KIND=<value>
Arguments
<value> |
Binary indicator |
release |
Multi-threaded optimized library. This is the default value |
debug |
Multi-threaded debug library |
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.bat release