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This commit is contained in:
Gabriele Cosmo
2020-12-04 12:30:43 +01:00
parent 67ba86d073
commit dab42d2018
3770 changed files with 226369 additions and 286486 deletions
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examples/extended/parallel/ThreadsafeScorers/README
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@@ -9,7 +9,7 @@
----------------------------
This example demonstrates a very simple application where an energy
deposit and # of steps is accounted in thread-local (i.e. one instance per
deposit and # of steps is accounted in thread-local (i.e. one instance per
thread) hits maps with underlying types of plain-old data (POD) and global
(i.e. one instance) hits maps with underlying types of atomics.
The example uses a coarse mesh, extensive physics, and step limiters
@@ -17,15 +17,15 @@
when updating the scorers to test the robustness of the atomics
classes and maximize the compounding of thread-local round-off error.
At the end of the simulation, the scorers are printed to
"mfd_<DATA_TYPE>_<SCORER_TYPE>.out", where DATA_TYPE is either
"mfd_<DATA_TYPE>_<SCORER_TYPE>.out", where DATA_TYPE is either
"tl" (thread-local) or "tg" (thread-global) and SCORER_TYPE is "EnergyDeposit"
or "NumberOfSteps". These values are then compared to a thread-global
sum of these scorers that were updated via mutex locking. If round-off
errors in thread-local EnergyDeposit are present, they can be viewed
in "mfd_diff.out" at the end of the simulation
This example also provides a demonstration of the TiMemory (timing and
memory analysis) package provided in Geant4 -- for documentation of TiMemory
see https://github.com/jrmadsen/TiMemory.
This example also provides a demonstration of the timemory (a performance
instrumentation toolkit) package provided in Geant4 -- for documentation of timemory
see https://github.com/NERSC/timemory and https://timemory.readthedocs.io.
1- ATOMICS and the ATOMIC SCORERS
@@ -38,33 +38,33 @@
in atomic.hh has limited copy-construction and still cannot be used in
STL containers. Use these copy-constructors with extreme caution. See
opening comments of G4atomic.hh for more details.
The newly provided classes in this example (G4atomic, G4TAtomicHitsMap, and
G4TAtomicHitsCollection) are intended for applications where memory is a
G4TAtomicHitsCollection) are intended for applications where memory is a
greater concern than performance. While atomics generally perform better than
mutex locking, the synchronization is not without a cost. However, since
the memory consumed by thread-local hits maps scales roughly linearly
with the number of threads, simulations with a large number of scoring
volumes can decrease simulation time by increasing the number of threads
volumes can decrease simulation time by increasing the number of threads
beyond what was previously allowed due to the increase in memory consumption.
The G4TAtomicHitsMap and G4TAtomicHitsCollection work exactly the same way
as the standard G4THitsMap and G4THitsCollection, respectively, with the
exception(s) that you should only implement one instance and provide a
exception(s) that you should only implement one instance and provide a
pointer/reference of that instance to the threads instead of having the
threads create them. Additionally, there is no need to include them
in the G4Run::Merge().
2- GEOMETRY DEFINITION
The geometry is constructed in the TSDetectorConstruction class.
The setup consists of a box filling the world. The volume is divided into
subregions, where the outermost boxes are a different material. The materials
by default are water and boron as these have large scattering cross-sections
for neutrons (the default particle).
by default are water and boron as these have large scattering cross-sections
for neutrons (the default particle).
3- PHYSICS LIST
The particle's type and the physic processes which will be available
in this example are set are built from a variety of physics constructors.
The chosen physics lists are extensive, primarily
@@ -90,28 +90,28 @@
in multi-threading mode the same method is invoked for each thread worker
and so all user action classes are defined thread-local.
A run action class is instantiated both thread-local
A run action class is instantiated both thread-local
and global that's why its instance is created also in the method
TSActionInitialization::BuildForMaster()
TSActionInitialization::BuildForMaster()
which is invoked only in multi-threading mode.
5- PRIMARY GENERATOR
The primary generator is defined in the TSPrimaryGeneratorAction class.
The default kinematics is a 1 MeV neutron, randomly distributed in front
of the target across 100% of the transverse (X,Y) target size.
This default setting can be changed via the Geant4 built-in commands
This default setting can be changed via the Geant4 built-in commands
of the G4ParticleGun class.
6- DETECTOR RESPONSE
This example demonstrates a scoring implemented
in the user action classes and TSRun object.
The energy deposited is collected per event in the PrimitiveScorer
G4PSEnergyDeposit (as part of a MultiFunctionalDetector)
and the thread-local version are merged at the end of the run.
The number of steps is collected per event in the PrimativeScorer
G4PSNoOfSteps and the thread-local version are merged at the end of the run.
@@ -162,7 +162,7 @@
and type in the commands from run.mac line by line:
Idle> /control/verbose 2
Idle> /tracking/verbose 1
Idle> /run/beamOn 10
Idle> /run/beamOn 10
Idle> ...
Idle> exit
or
@@ -177,14 +177,12 @@
8- TIMEMORY USAGE
This example demonstrates timing and memory analysis with TiMemory
(https://github.com/jrmadsen/TiMemory).
This example demonstrates profiling analysis with timemory
(https://github.com/NERSC/timemory).
- Compile Geant4 with TiMemory (-DGEANT4_USE_TIMEMORY=ON)
- TiMemory auto-timer provide timing within the Geant4 source code
- Compile Geant4 with timemory (-DGEANT4_USE_TIMEMORY=ON)
- timemory provide timing within the Geant4 source code
and within the example (TSRun::RecordEvent)
- Analysis is echoed to stdout, recorded in ts_scorers.out, and
serialized in ts_scorers.json
- Generates plots:
"timemory-plotter -f ts_scorers.json -t "ThreadSafe Scorers" -o plots -e"
- Uploads plots to CDash if enabled
- Analysis is echoed to stdout and generates several output
files in a folder based on the name of the executable. In
general that folder will be "timemory-{name of executable}-output"