gmx-tune_pme - Online in the Cloud

PROGRAM:

NAME

gmx-tune_pme - Time mdrun as a function of PME ranks to optimize settings

SYNOPSIS

gmx tune_pme [-s [<.tpr>]] [-cpi [<.cpt>]] [-table [<.xvg>]]
[-tabletf [<.xvg>]] [-tablep [<.xvg>]]
[-tableb [<.xvg>]] [-rerun [<.xtc/.trr/...>]]
[-ei [<.edi>]] [-p [<.out>]] [-err [<.log>]]
[-so [<.tpr>]] [-o [<.trr/.cpt/...>]] [-x [<.xtc/.tng>]]
[-cpo [<.cpt>]] [-c [<.gro/.g96/...>]] [-e [<.edr>]]
[-g [<.log>]] [-dhdl [<.xvg>]] [-field [<.xvg>]]
[-tpi [<.xvg>]] [-tpid [<.xvg>]] [-eo [<.xvg>]]
[-devout [<.xvg>]] [-runav [<.xvg>]] [-px [<.xvg>]]
[-pf [<.xvg>]] [-ro [<.xvg>]] [-ra [<.log>]]
[-rs [<.log>]] [-rt [<.log>]] [-mtx [<.mtx>]]
[-dn [<.ndx>]] [-swap [<.xvg>]] [-bo [<.trr/.cpt/...>]]
[-bx [<.xtc>]] [-bcpo [<.cpt>]] [-bc [<.gro/.g96/...>]]
[-be [<.edr>]] [-bg [<.log>]] [-beo [<.xvg>]]
[-bdhdl [<.xvg>]] [-bfield [<.xvg>]] [-btpi [<.xvg>]]
[-btpid [<.xvg>]] [-bdevout [<.xvg>]] [-brunav [<.xvg>]]
[-bpx [<.xvg>]] [-bpf [<.xvg>]] [-bro [<.xvg>]]
[-bra [<.log>]] [-brs [<.log>]] [-brt [<.log>]]
[-bmtx [<.mtx>]] [-bdn [<.ndx>]] [-bswap [<.xvg>]]
[-xvg <enum>] [-mdrun <string>] [-np <int>]
[-npstring <enum>] [-ntmpi <int>] [-r <int>]
[-max <real>] [-min <real>] [-npme <enum>] [-fix <int>]
[-rmax <real>] [-rmin <real>] [-[no]scalevdw]
[-ntpr <int>] [-steps <int>] [-resetstep <int>]
[-nsteps <int>] [-[no]launch] [-[no]bench] [-[no]check]
[-gpu_id <string>] [-[no]append] [-[no]cpnum]
[-deffnm <string>]

DESCRIPTION

For a given number -np or -ntmpi of ranks, gmx tune_pme systematically times gmx mdrun
with various numbers of PME-only ranks and determines which setting is fastest. It will
also test whether performance can be enhanced by shifting load from the reciprocal to the
real space part of the Ewald sum. Simply pass your .tpr file to gmx tune_pme together
with other options for gmx mdrun as needed.

gmx tune_pme needs to call gmx mdrun and so requires that you specify how to call mdrun
with the argument to the -mdrun parameter. Depending how you have built GROMACS, values
such as 'gmx mdrun', 'gmx_d mdrun', or 'mdrun_mpi' might be needed.

The program that runs MPI programs can be set in the environment variable MPIRUN (defaults
to 'mpirun'). Note that for certain MPI frameworks, you need to provide a machine- or
hostfile. This can also be passed via the MPIRUN variable, e.g.

export MPIRUN="/usr/local/mpirun -machinefile hosts" Note that in such cases it is
normally necessary to compile and/or run gmx tune_pme without MPI support, so that it can
call the MPIRUN program.

Before doing the actual benchmark runs, gmx tune_pme will do a quick check whether gmx
mdrun works as expected with the provided parallel settings if the -check option is
activated (the default). Please call gmx tune_pme with the normal options you would pass
to gmx mdrun and add -np for the number of ranks to perform the tests on, or -ntmpi for
the number of threads. You can also add -r to repeat each test several times to get better
statistics.

gmx tune_pme can test various real space / reciprocal space workloads for you. With -ntpr
you control how many extra .tpr files will be written with enlarged cutoffs and smaller
Fourier grids respectively. Typically, the first test (number 0) will be with the
settings from the input .tpr file; the last test (number ntpr) will have the Coulomb
cutoff specified by -rmax with a somewhat smaller PME grid at the same time. In this last
test, the Fourier spacing is multiplied with rmax/rcoulomb. The remaining .tpr files will
have equally-spaced Coulomb radii (and Fourier spacings) between these extremes. Note that
you can set -ntpr to 1 if you just seek the optimal number of PME-only ranks; in that case
your input .tpr file will remain unchanged.

For the benchmark runs, the default of 1000 time steps should suffice for most MD systems.
The dynamic load balancing needs about 100 time steps to adapt to local load imbalances,
therefore the time step counters are by default reset after 100 steps. For large systems
(>1M atoms), as well as for a higher accuracy of the measurements, you should set
-resetstep to a higher value. From the 'DD' load imbalance entries in the md.log output
file you can tell after how many steps the load is sufficiently balanced. Example call:

gmx tune_pme -np 64 -s protein.tpr -launch

After calling gmx mdrun several times, detailed performance information is available in
the output file perf.out. Note that during the benchmarks, a couple of temporary files
are written (options -b*), these will be automatically deleted after each test.

If you want the simulation to be started automatically with the optimized parameters, use
the command line option -launch.

Basic support for GPU-enabled mdrun exists. Give a string containing the IDs of the GPUs
that you wish to use in the optimization in the -gpu_id command-line argument. Unlike
mdrun -gpu_id, this does not imply a mapping but merely the eligible set. g_tune_pme will
construct calls to mdrun that use this set appropriately, assuming that PP ranks with low
indices should map to GPUs with low indices, and increasing both monotonically over the
respective sets.

OPTIONS

Options to specify input files:

-s [<.tpr>] (topol.tpr)
Portable xdr run input file

-cpi [<.cpt>] (state.cpt) (Optional)
Checkpoint file

-table [<.xvg>] (table.xvg) (Optional)
xvgr/xmgr file

-tabletf [<.xvg>] (tabletf.xvg) (Optional)
xvgr/xmgr file

-tablep [<.xvg>] (tablep.xvg) (Optional)
xvgr/xmgr file

-tableb [<.xvg>] (table.xvg) (Optional)
xvgr/xmgr file

-rerun [<.xtc/.trr/...>] (rerun.xtc) (Optional)
Trajectory: xtc trr cpt gro g96 pdb tng

-ei [<.edi>] (sam.edi) (Optional)
ED sampling input

Options to specify output files:

-p [<.out>] (perf.out)
Generic output file

-err [<.log>] (bencherr.log)
Log file

-so [<.tpr>] (tuned.tpr)
Portable xdr run input file

-o [<.trr/.cpt/...>] (traj.trr)
Full precision trajectory: trr cpt tng

-x [<.xtc/.tng>] (traj_comp.xtc) (Optional)
Compressed trajectory (tng format or portable xdr format)

-cpo [<.cpt>] (state.cpt) (Optional)
Checkpoint file

-c [<.gro/.g96/...>] (confout.gro)
Structure file: gro g96 pdb brk ent esp

-e [<.edr>] (ener.edr)
Energy file

-g [<.log>] (md.log)
Log file

-dhdl [<.xvg>] (dhdl.xvg) (Optional)
xvgr/xmgr file

-field [<.xvg>] (field.xvg) (Optional)
xvgr/xmgr file

-tpi [<.xvg>] (tpi.xvg) (Optional)
xvgr/xmgr file

-tpid [<.xvg>] (tpidist.xvg) (Optional)
xvgr/xmgr file

-eo [<.xvg>] (edsam.xvg) (Optional)
xvgr/xmgr file

-devout [<.xvg>] (deviatie.xvg) (Optional)
xvgr/xmgr file

-runav [<.xvg>] (runaver.xvg) (Optional)
xvgr/xmgr file

-px [<.xvg>] (pullx.xvg) (Optional)
xvgr/xmgr file

-pf [<.xvg>] (pullf.xvg) (Optional)
xvgr/xmgr file

-ro [<.xvg>] (rotation.xvg) (Optional)
xvgr/xmgr file

-ra [<.log>] (rotangles.log) (Optional)
Log file

-rs [<.log>] (rotslabs.log) (Optional)
Log file

-rt [<.log>] (rottorque.log) (Optional)
Log file

-mtx [<.mtx>] (nm.mtx) (Optional)
Hessian matrix

-dn [<.ndx>] (dipole.ndx) (Optional)
Index file

-swap [<.xvg>] (swapions.xvg) (Optional)
xvgr/xmgr file

-bo [<.trr/.cpt/...>] (bench.trr)
Full precision trajectory: trr cpt tng

-bx [<.xtc>] (bench.xtc)
Compressed trajectory (portable xdr format): xtc

-bcpo [<.cpt>] (bench.cpt)
Checkpoint file

-bc [<.gro/.g96/...>] (bench.gro)
Structure file: gro g96 pdb brk ent esp

-be [<.edr>] (bench.edr)
Energy file

-bg [<.log>] (bench.log)
Log file

-beo [<.xvg>] (benchedo.xvg) (Optional)
xvgr/xmgr file

-bdhdl [<.xvg>] (benchdhdl.xvg) (Optional)
xvgr/xmgr file

-bfield [<.xvg>] (benchfld.xvg) (Optional)
xvgr/xmgr file

-btpi [<.xvg>] (benchtpi.xvg) (Optional)
xvgr/xmgr file

-btpid [<.xvg>] (benchtpid.xvg) (Optional)
xvgr/xmgr file

-bdevout [<.xvg>] (benchdev.xvg) (Optional)
xvgr/xmgr file

-brunav [<.xvg>] (benchrnav.xvg) (Optional)
xvgr/xmgr file

-bpx [<.xvg>] (benchpx.xvg) (Optional)
xvgr/xmgr file

-bpf [<.xvg>] (benchpf.xvg) (Optional)
xvgr/xmgr file

-bro [<.xvg>] (benchrot.xvg) (Optional)
xvgr/xmgr file

-bra [<.log>] (benchrota.log) (Optional)
Log file

-brs [<.log>] (benchrots.log) (Optional)
Log file

-brt [<.log>] (benchrott.log) (Optional)
Log file

-bmtx [<.mtx>] (benchn.mtx) (Optional)
Hessian matrix

-bdn [<.ndx>] (bench.ndx) (Optional)
Index file

-bswap [<.xvg>] (benchswp.xvg) (Optional)
xvgr/xmgr file

Other options:

-xvg <enum>
xvg plot formatting: xmgrace, xmgr, none

-mdrun <string>
Command line to run a simulation, e.g. 'gmx mdrun' or 'mdrun_mpi'

-np <int> (1)
Number of ranks to run the tests on (must be > 2 for separate PME ranks)

-npstring <enum> (np)
Name of the $MPIRUN option that specifies the number of ranks to use ('np', or 'n';
use 'none' if there is no such option): np, n, none

-ntmpi <int> (1)
Number of MPI-threads to run the tests on (turns MPI & mpirun off)

-r <int> (2)
Repeat each test this often

-max <real> (0.5)
Max fraction of PME ranks to test with

-min <real> (0.25)
Min fraction of PME ranks to test with

-npme <enum> (auto)
Within -min and -max, benchmark all possible values for -npme, or just a reasonable
subset. Auto neglects -min and -max and chooses reasonable values around a guess
for npme derived from the .tpr: auto, all, subset

-fix <int> (-2)
If >= -1, do not vary the number of PME-only ranks, instead use this fixed value
and only vary rcoulomb and the PME grid spacing.

-rmax <real> (0)
If >0, maximal rcoulomb for -ntpr>1 (rcoulomb upscaling results in fourier grid
downscaling)

-rmin <real> (0)
If >0, minimal rcoulomb for -ntpr>1

-[no]scalevdw (yes)
Scale rvdw along with rcoulomb

-ntpr <int> (0)
Number of .tpr files to benchmark. Create this many files with different rcoulomb
scaling factors depending on -rmin and -rmax. If < 1, automatically choose the
number of .tpr files to test

-steps <int> (1000)
Take timings for this many steps in the benchmark runs

-resetstep <int> (100)
Let dlb equilibrate this many steps before timings are taken (reset cycle counters
after this many steps)

-nsteps <int> (-1)
If non-negative, perform this many steps in the real run (overwrites nsteps from
.tpr, add .cpt steps)

-[no]launch (no)
Launch the real simulation after optimization

-[no]bench (yes)
Run the benchmarks or just create the input .tpr files?

-[no]check (yes)
Before the benchmark runs, check whether mdrun works in parallel

-gpu_id <string>
List of GPU device id-s that are eligible for use (unlike mdrun, does not imply any
mapping)

-[no]append (yes)
Append to previous output files when continuing from checkpoint instead of adding
the simulation part number to all file names (for launch only)

-[no]cpnum (no)
Keep and number checkpoint files (launch only)

-deffnm <string>
Set the default filenames (launch only)

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