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Barrier required in parallel when we use ftell

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This commit is contained in:
paboyle 2018-03-30 12:41:30 +01:00
parent 2f5add4d5f
commit 5bde64d48b
1 changed files with 24 additions and 6 deletions
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30
lib/parallelIO/IldgIO.h
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@ -350,26 +350,36 @@ class GridLimeWriter : public BinaryIO {
// iv) fseek on FILE * to end of this disjoint section.
// v) Continue writing scidac record.
////////////////////////////////////////////////////////////////////
GridBase *grid = field._grid;
////////////////////////////////////////////
// Create record header
////////////////////////////////////////////
typedef typename vobj::scalar_object sobj;
int err;
uint32_t nersc_csum,scidac_csuma,scidac_csumb;
uint64_t PayloadSize = sizeof(sobj) * field._grid->_gsites;
uint64_t PayloadSize = sizeof(sobj) * grid->_gsites;
createLimeRecordHeader(record_name, 0, 0, PayloadSize);
fflush(File);
// std::cout << "W sizeof(sobj)" <<sizeof(sobj)<<std::endl;
// std::cout << "W Gsites " <<field._grid->_gsites<<std::endl;
// std::cout << "W Payload expected " <<PayloadSize<<std::endl;
fflush(File);
////////////////////////////////////////////////
// Check all nodes agree on file position
////////////////////////////////////////////////
uint64_t offset1 = ftello(File);
uint64_t compare = offset1;
grid->Broadcast(0,(void *)&compare,sizeof(compare));
assert(compare == offset1 );
///////////////////////////////////////////
// Write by other means into the binary record
///////////////////////////////////////////
uint64_t offset1 = ftello(File); // std::cout << " Writing to offset "<<offset1 << std::endl;
std::string format = getFormatString<vobj>();
BinarySimpleMunger<sobj,sobj> munge;
BinaryIO::writeLatticeObject<vobj,sobj>(field, filename, munge, offset1, format,nersc_csum,scidac_csuma,scidac_csumb);
@ -380,7 +390,15 @@ class GridLimeWriter : public BinaryIO {
fseek(File,0,SEEK_END);
uint64_t offset2 = ftello(File); // std::cout << " now at offset "<<offset2 << std::endl;
assert((offset2-offset1) == PayloadSize);
/////////////////////////////////////////////////////////////
// Must synchronise the nodes so no race between nodes
/////////////////////////////////////////////////////////////
grid->Barrier();
/////////////////////////////////////////////////////////////
// Check MPI-2 I/O did what we expect to file
/////////////////////////////////////////////////////////////
assert( (offset2-offset1) == PayloadSize);
err=limeWriterCloseRecord(LimeW); assert(err>=0);