Environnement Commun Linux

en construction(cette page s'adresse principalement aux développeurs)

under construction(this page is mainly for developers)

• Useful environment variables
  • PATH : colon ':' separated list of directories where executables or sourced (.) shell includes are to be found
    
  • LD_LIBRARY_PATH : colon ':' separated list of directories where dynamic libraries (.so files) needed by executables can be found
    
  • EC_LD_LIBRARY_PATH : colon ':' separated list of directories where s.compile, s.f90  et al. will look for libraries
    
  • EC_INCLUDE_PATH : colon ':' separated list of directories where s.compile, s.f90  et al. will look for include files
    
  • BASE_ARCH : name of the hardware architecture of the machine
  • EC_ARCH : name of the hardware+software architecture of the machine (BASE_ARCH + compiler usually)
• Useful memory layout information
  • Linux memory layout
    

128 TB ---------------------------------  Top of memory

                 |   thread 0 (master) stack
                 |   local variables
                \ /



                / \
                 |
                 |   heap (allocate/malloc)

~44 TB --------------------------------- 

                 |   thread N stack
                 |
                \ /

                 |   thread N-1 stack
                 |
                \ /

                ...

                 |   thread 1 stack
                 |
                \ /


                / \
                 |   code + static data
                 |   (common blocks + some main program arrays)
                 |

000 ---------------------------------- Bottom of memory 

• • OMP_STACKSIZE environment variable controls thread (>0) stack size
• Useful information about system
  • /proc/cpuinfo : pseudo file containing a full description of logical cpus in a linux system (cat/less/more)<br>
• useful commands<br>
  • r.mpirun : script front end to mpiexec hiding machine/mpi implementation specific details
  • soumet : script used to submit jobs, hiding machine/batch subsystem specific details<br>