XALT’s environment variables

There are a few environment variables that must be set in order for XALT to work correctly.

XALT_EXECUTABLE_TRACKINGThis variable must be set to yes

otherwise there is no XALT tracking

XALT_DIRThis directory is the base directory where XALT is

installed on your system. This is the directory that contains bin, include, lib, lib64, etc.

LD_PRELOADThis path like variable contains the path to the

libxalt_init.so file.

XALT_SAMPLINGThis variable should be set to yes unless you

are testing XALT.

COMPILER_PATHFor the gnu and intel compilers this needs to be

set to the bin directory containing the ld program from XALT.

XALT_SCALAR_TRACKINGNormally configured to be yes it can be

overridden by an environment variable. yes is on and anything else is off.

XALT_MPI_TRACKINGNormally configured to be yes it can be

overridden by an environment variable. yes is on and anything else is off.

XALT_GPU_TRACKINGCan be configured to be yes it can be

overridden by an environment variable. yes is on and anything else is off.

XALT_SIGNAL_HANDLERNormally XALT disables the signal handler to

catch FPE, etc. Setting this variable to yes enables this feature.

Debugging variables for XALT

XALT_TRACING : This variable allows for debugging the actions of XALT.

This variable can take several values:

link : This will tracing the linking steps and write the results to stderr.

link:<file>This will write the XALT link tracing to <file>.

(e.g. link:linker.log will write the tracing to the file linker.log instead of stderr)

yesThis will tracing the execution of a program under XALT. This

gives the most information. This option will report whether an execution will be tracked or why not.

yes0This will tracing the execution of a program under XALT but

only for task 0. This option will report whether an execution will be tracked or why not for task 0.

runThis shows output just like yes except that there is only

output when the executable is acceptable by the path test and it is task 0.

Special Debugging variables for XALT

XALT_TESTING_RUNTIMEIf this variable is set, XALT uses it to be

the runtime for the executable instead of the real runtime. Obviously this is useful when testing the sampling rules.

XALT_COMM_WORLD_SIZEIf this variable is set, XALT will use this

value as the number of MPI tasks. Note that it won’t affect the number of real MPI tasks.

XALT_MPI_ALWAYS_RECORDXALT will use this env. variable instead

of the configured value.

XALT_DUMP_ENVSetting this variable to yes will print the

current environment to stderr.

Environment variable pushed by XALT

XALT_RUN_UUIDThe current run uuid created by XALT. This is

used by programs such as python, R and MATLAB so that they know what executable has been called. Program like python can track imports. This env. variable is part of that mechanism.

XALT_DIR : The location of the XALT programs

XALT_DATE_TIMEThe current date and time of when the current

executable was started.