Changes between Initial Version and Version 1 of Public/User_Guide/OpenCHK

Timestamp:

Jun 18, 2019, 11:20:54 AM (5 years ago)

Author:

Marcos Maronas Bravo

Comment:

—

Public/User_Guide/OpenCHK

@@ +1 @@
+== What is OpenCHK?  
+
+The OpenCHK model is a pragma-based checkpointing model developed by the Programming Models group at the Barcelona Supercomputing Center.
+
+The aim of this model is to provide a generic and portable way to checkpoint and recover data in C/C++ and Fortran High Performance Computing applications.
+
+The prototype implementation of the model is based on two software components:
+
+Mercurium source-to-source compiler
+Transparent Checkpoint Library
+
+= Loading the OpenCHK module 
+ 
+Firstly, it is required to append some paths to your "MODULEPATH" environment variable:
+
+
+{{{
+modulepath="/usr/local/software/skylake/Stages/2018b/modules/all/Core:$modulepath"
+modulepath="/usr/local/software/skylake/Stages/2018b/modules/all/Compiler/mpi/intel/2019.0.117-GCC-7.3.0:$modulepath"
+modulepath="/usr/local/software/skylake/Stages/2018b/modules/all/MPI/intel/2019.0.117-GCC-7.3.0/psmpi/5.2.1-1-mt:$modulepath"
+export MODULEPATH="$modulepath:$MODULEPATH"
+}}}
+
+
+Once this is done, simply load the following modules:
+
+
+{{{
+module load Intel/2019.0.117-GCC-7.3.0
+module load ParaStationMPI/5.2.1-1-mt
+module load OpenCHK/1.0
+}}}
+
+= Documentation and User guide  
+
+Manual: https://github.com/bsc-pm/OpenCHK-model
+
+= Quick Start Guide
+
+== Before the Execution
+TCL provides support for three different backends: FTI, SCR and VeloC. The backend library must be chosen using the environment variable "TCL_BACKEND". \\
+NOTE: In the current installation, the only enabled backend is FTI.
+
+{{{
+export TCL_BACKEND=FTI
+}}}
+
+
+When using FTI as backend library, the user needs to provide an FTI configuration file using the environment variable "FTI_CONF_FILE". (see attachments: config.fti)
+
+{{{
+export FTI_CONF_FILE=config.fti
+}}}
+
+
+== OpenCHK syntax
+* The ''init'' construct defines the initialization of a checkpoint context. None of the other constructs must be used without initializing a checkpoint context. \\
+* The ''shutdown'' construct defines the finalization of a checkpoint context.
+* The 'store' construct specifies that some variables and memory regions are going to be saved in a new checkpoint.
+* The 'load' construct specifies that some variables and memory regions are goind to be updated with the stored values that we have previously checkpointed (if any).
+
+== Example C/C++
+Compile the example:
+
+{{{
+mpicxx -cxx=mcxx  --checkpoint -o test_scalar-cpp test_scalar.cpp
+}}}
+
+Run the example: \\
+NOTE: Remember that you should have set TCL_BACKEND=FTI and a valid FTI_CONF_FILE.
+
+{{{
+mpirun -np 8 ./test_scalar-cpp [step_to_inject_error]
+}}}
+
+
+{{{#!C++
+#include <iostream>
+#include <cassert>
+#include <stdlib.h>
+
+void error_handler(int err_code)
+{
+    std::cout << "Error inside CheckpointLib. Error code: " << err_code << "." << std::endl;
+    exit(-1);
+}
+
+int main(int argc, char **argv)
+{
+    int err = MPI_Init(&argc, &argv);
+    assert(err == MPI_SUCCESS);
+    MPI_Comm comm = MPI_COMM_WORLD;
+
+    int inject_error = -1;
+    if(argc == 2) {
+        inject_error = std::atoi(argv[1]);
+        std::cout << "Inject error at step " << inject_error << "." << std::endl;
+    }
+
+    #pragma chk init comm(comm)
+    {
+        int data, i = 0;
+        bool restored = false;
+
+        #pragma chk load(i, data)
+        if(i != 0) {
+            std::cout << "Restored data from iteration " << i << ". data = " << data << "." << std::endl;
+            restored = true;
+        }
+        for(i; i < 10; i++) {
+            data = i;
+            #pragma chk store(i, data) kind(CHK_FULL) id(i) level((i%4)+1) if(1) handler(error_handler)
+            if(i == inject_error && !restored) {
+                std::cout << "Injected error." << std::endl;
+                exit(-1);
+            }
+            std::cout << "Completed step " << i << std::endl;
+        }
+    }
+    #pragma chk shutdown
+
+    MPI_Finalize();
+}
+}}} 
+
+== Example Fortran
+Compile the example:
+
+{{{
+mpif90 -fc=ifort-mfc  --checkpoint -o test_scalar-fortran test_scalar.f90
+}}}
+
+Run the example: \\
+NOTE: Remember that you should have set TCL_BACKEND=FTI and a valid FTI_CONF_FILE.
+
+{{{
+mpirun -np 8 ./test_scalar-fortran [step_to_inject_error]
+}}}
+
+
+{{{#!Fortran
+PROGRAM T1
+   include 'mpif.h'
+   integer rank, size, ierror, tag, comm, status(MPI_STATUS_SIZE)
+   integer actual_data = 0, restored_i = 0, restored = 0, inject_error = -1, i
+    CHARACTER(len=32) :: arg
+
+   call MPI_INIT(ierror)
+   comm = MPI_COMM_WORLD
+
+   if (iargc() == 1) then
+       call getarg(1, arg)
+       read (arg,'(I10)') inject_error
+       print *, 'Inject error at step ', inject_error, '.'
+   endif
+
+!$chk init comm(comm)
+!$chk load(restored_i, actual_data)
+   if (restored_i .ne. 0) then
+       print *, 'Restored data from iteration ', restored_i , '. data = ', actual_data, '.'
+       restored = 1
+   end if
+
+   do i = restored_i, 10
+       actual_data = i
+!$chk store(i, actual_data) kind(0) id(i) level(mod(i,4)+1) if(i .ge. 0)
+       if (i .eq. inject_error .AND. restored .eq. 0) then
+           print *, 'Injected error'
+           call EXIT(-1)
+       end if
+       print *, 'Completed step ', i
+   end do
+!$chk shutdown
+
+   call MPI_FINALIZE(ierror)
+END PROGRAM
+}}}