Improvements to existing functionality
--------------------------------------
- MPI is initialised without thread support if it is not needed e.g. uncollated
- Use native c++11 threading; avoids problem with static destruction order.
- etc/cellModels now only read if needed.
- etc/controlDict can now be read from the environment variable FOAM_CONTROLDICT
- Uniform files (e.g. '0/uniform/time') are now read only once on the master only
(with the masterUncollated or collated file handlers)
- collated format writes to 'processorsNNN' instead of 'processors'. The file
format is unchanged.
- Thread buffer and file buffer size are no longer limited to 2Gb.
The global controlDict file contains parameters for file handling. Under some
circumstances, e.g. running in parallel on a system without NFS, the user may
need to set some parameters, e.g. fileHandler, before the global controlDict
file is read from file. To support this, OpenFOAM now allows the global
controlDict to be read as a string set to the FOAM_CONTROLDICT environment
variable.
The FOAM_CONTROLDICT environment variable can be set to the content the global
controlDict file, e.g. from a sh/bash shell:
export FOAM_CONTROLDICT=$(foamDictionary $FOAM_ETC/controlDict)
FOAM_CONTROLDICT can then be passed to mpirun using the -x option, e.g.:
mpirun -np 2 -x FOAM_CONTROLDICT simpleFoam -parallel
Note that while this avoids the need for NFS to read the OpenFOAM configuration
the executable still needs to load shared libraries which must either be copied
locally or available via NFS or equivalent.
New: Multiple IO ranks
----------------------
The masterUncollated and collated fileHandlers can now use multiple ranks for
writing e.g.:
mpirun -np 6 simpleFoam -parallel -ioRanks '(0 3)'
In this example ranks 0 ('processor0') and 3 ('processor3') now handle all the
I/O. Rank 0 handles 0,1,2 and rank 3 handles 3,4,5. The set of IO ranks should always
include 0 as first element and be sorted in increasing order.
The collated fileHandler uses the directory naming processorsNNN_XXX-YYY where
NNN is the total number of processors and XXX and YYY are first and last
processor in the rank, e.g. in above example the directories would be
processors6_0-2
processors6_3-5
and each of the collated files in these contains data of the local ranks
only. The same naming also applies when e.g. running decomposePar:
decomposePar -fileHandler collated -ioRanks '(0 3)'
New: Distributed data
---------------------
The individual root directories can be placed on different hosts with different
paths if necessary. In the current framework it is necessary to specify the
root per slave process but this has been simplified with the option of specifying
the root per host with the -hostRoots command line option:
mpirun -np 6 simpleFoam -parallel -ioRanks '(0 3)' \
-hostRoots '("machineA" "/tmp/" "machineB" "/tmp")'
The hostRoots option is followed by a list of machine name + root directory, the
machine name can contain regular expressions.
New: hostCollated
-----------------
The new hostCollated fileHandler automatically sets the 'ioRanks' according to
the host name with the lowest rank e.g. to run simpleFoam on 6 processors with
ranks 0-2 on machineA and ranks 3-5 on machineB with the machines specified in
the hostfile:
mpirun -np 6 --hostfile hostfile simpleFoam -parallel -fileHandler hostCollated
This is equivalent to
mpirun -np 6 --hostfile hostfile simpleFoam -parallel -fileHandler collated -ioRanks '(0 3)'
This example will write directories:
processors6_0-2/
processors6_3-5/
A typical example would use distributed data e.g. no two nodes, machineA and
machineB, each with three processes:
decomposePar -fileHandler collated -case cavity
# Copy case (constant/*, system/*, processors6/) to master:
rsync -a cavity machineA:/tmp/
# Create root on slave:
ssh machineB mkdir -p /tmp/cavity
# Run
mpirun --hostfile hostfile icoFoam \
-case /tmp/cavity -parallel -fileHandler hostCollated \
-hostRoots '("machineA" "/tmp" "machineB" "/tmp")'
Contributed by Mattijs Janssens
- controlled by the the 'printExecutionFormat' InfoSwitch in
etc/controlDict
// Style for "ExecutionTime = " output
// - 0 = seconds (with trailing 's')
// - 1 = day-hh:mm:ss
ExecutionTime = 112135.2 s ClockTime = 113017 s
ExecutionTime = 1-07:08:55.20 ClockTime = 1-07:23:37
- Callable via the new Time::printExecutionTime() method,
which also helps to reduce clutter in the applications.
Eg,
runTime.printExecutionTime(Info);
vs
Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
<< " ClockTime = " << runTime.elapsedClockTime() << " s"
<< nl << endl;
--
ENH: return elapsedClockTime() and clockTimeIncrement as double
- previously returned as time_t, which is less portable.
- IOstreamOption class to encapsulate format, compression, version.
This is ordered to avoid internal padding in the structure, which
reduces several bytes of memory overhead for stream objects
and other things using this combination of data.
Byte-sizes:
old IOstream:48 PstreamBuffers:88 Time:928
new IOstream:24 PstreamBuffers:72 Time:904
====
STYLE: remove support for deprecated uncompressed/compressed selectors
In older versions, the system/controlDict used these types of
specifications:
writeCompression uncompressed;
writeCompression compressed;
As of DEC-2009, these were deprecated in favour of using normal switch
names:
writeCompression true;
writeCompression false;
writeCompression on;
writeCompression off;
Now removed these deprecated names and treat like any other unknown
input and issue a warning. Eg,
Unknown compression specifier 'compressed', assuming no compression
====
STYLE: provide Enum of stream format names (ascii, binary)
====
COMP: fixed incorrect IFstream construct in FIREMeshReader
- spurious bool argument (presumably meant as uncompressed) was being
implicitly converted to a versionNumber. Now caught by making
IOstreamOption::versionNumber constructor explicit.
- bad version specifier in changeDictionary
- in many cases can just use lookupOrDefault("key", bool) instead of
lookupOrDefault<bool> or lookupOrDefault<Switch> since reading a
bool from an Istream uses the Switch(Istream&) anyhow
STYLE: relocated Switch string names into file-local scope
- use succincter method names that more closely resemble dictionary
and HashTable method names. This improves method name consistency
between classes and also requires less typing effort:
args.found(optName) vs. args.optionFound(optName)
args.readIfPresent(..) vs. args.optionReadIfPresent(..)
...
args.opt<scalar>(optName) vs. args.optionRead<scalar>(optName)
args.read<scalar>(index) vs. args.argRead<scalar>(index)
- the older method names forms have been retained for code compatibility,
but are now deprecated
- expose the names of write and stopAt controls for reuse elsewhere and
provide a stopAtControls enum for 'unknown'
- track the requested number of sub-cycles (was previously a bool)
Original commit message:
------------------------
Parallel IO: New collated file format
When an OpenFOAM simulation runs in parallel, the data for decomposed fields and
mesh(es) has historically been stored in multiple files within separate
directories for each processor. Processor directories are named 'processorN',
where N is the processor number.
This commit introduces an alternative "collated" file format where the data for
each decomposed field (and mesh) is collated into a single file, which is
written and read on the master processor. The files are stored in a single
directory named 'processors'.
The new format produces significantly fewer files - one per field, instead of N
per field. For large parallel cases, this avoids the restriction on the number
of open files imposed by the operating system limits.
The file writing can be threaded allowing the simulation to continue running
while the data is being written to file. NFS (Network File System) is not
needed when using the the collated format and additionally, there is an option
to run without NFS with the original uncollated approach, known as
"masterUncollated".
The controls for the file handling are in the OptimisationSwitches of
etc/controlDict:
OptimisationSwitches
{
...
//- Parallel IO file handler
// uncollated (default), collated or masterUncollated
fileHandler uncollated;
//- collated: thread buffer size for queued file writes.
// If set to 0 or not sufficient for the file size threading is not used.
// Default: 2e9
maxThreadFileBufferSize 2e9;
//- masterUncollated: non-blocking buffer size.
// If the file exceeds this buffer size scheduled transfer is used.
// Default: 2e9
maxMasterFileBufferSize 2e9;
}
When using the collated file handling, memory is allocated for the data in the
thread. maxThreadFileBufferSize sets the maximum size of memory in bytes that
is allocated. If the data exceeds this size, the write does not use threading.
When using the masterUncollated file handling, non-blocking MPI communication
requires a sufficiently large memory buffer on the master node.
maxMasterFileBufferSize sets the maximum size in bytes of the buffer. If the
data exceeds this size, the system uses scheduled communication.
The installation defaults for the fileHandler choice, maxThreadFileBufferSize
and maxMasterFileBufferSize (set in etc/controlDict) can be over-ridden within
the case controlDict file, like other parameters. Additionally the fileHandler
can be set by:
- the "-fileHandler" command line argument;
- a FOAM_FILEHANDLER environment variable.
A foamFormatConvert utility allows users to convert files between the collated
and uncollated formats, e.g.
mpirun -np 2 foamFormatConvert -parallel -fileHandler uncollated
An example case demonstrating the file handling methods is provided in:
$FOAM_TUTORIALS/IO/fileHandling
The work was undertaken by Mattijs Janssens, in collaboration with Henry Weller.
Time: call functionObject 'execute()' and 'end()' for last time-step
Now the operation of functionObject 'end()' call is consistent between running and post-processing
- this option overrides any controlDict settings as a convenient means
to selecting profiling without messing with the controlDict.
- provide Profiling::writeNow() to emit profiling for utilities that
don't have any natural time increment mechanism to trigger it.
- basic cpuInfo (model identification, MHz, etc)
- process memInfo
- profiling is activated via the case system/controlDict by
adding a "profiling" sub-dictionary.
Simply add the following (everything enabled):
profiling
{}
Which corresponds to the longer form:
profiling
{
active true; // default: true
cpuInfo true; // default: true
memInfo true; // default: true
sysInfo true; // default: true
}
This can be used to selectively disable any extra information
(eg, you don't want anyone else to know what hardware was used).
the equivalent functionality is provided by the writeRegisteredObject
functionObject in a MUCH simpler, easier and extensible manner.
functionObject: Removed the now redundant 'timeSet' function.
to have the prefix 'write' rather than 'output'
So outputTime() -> writeTime()
but 'outputTime()' is still supported for backward-compatibility.
Also removed the redundant secondary-writing functionality from Time
which has been superseded by the 'writeRegisteredObject' functionObject.
Simplified and generalized the handling of functionObjects which fail to
construct by removing them from the list rather than maintaining an
"enabled" switch in each functionObject.
Moved file path handling to regIOobject and made it type specific so
now every object can have its own rules. Examples:
- faceZones are now processor local (and don't search up anymore)
- timeStampMaster is now no longer hardcoded inside IOdictionary
(e.g. uniformDimensionedFields support it as well)
- the distributedTriSurfaceMesh is properly processor-local; no need
for fileModificationChecking manipulation.
- old convention was that on last time step it would only call end()
and not execute()
- however this meant that e.g. the functionObjectProperties file
did not get written
- and almost all functionObjects were doing an execute() inside of end()
- new convention: call execute() on last time step, just before doing end()
Avoids unnecessary increases in precision during intermediate steps for
cases with adjustable time-step which may require very high precision to
represent the time name.
