timers.txt
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timers.txt
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			"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

			:link(lws,http://lammps.sandia.gov)
			:link(ld,Manual.html)
			:link(lc,Section_commands.html#comm)

			:line

			timestep command :h3

			[Syntax:]

			timers args :pre

			{args} = one or more of {off} or {loop} or {normal} or {full} or {sync} or {nosync} :l
			{off} = do not collect and print timing information
			{loop} = collect only the total time for the simulation loop
			{normal} = collect timer information broken down in sections (default)
			{full} = like {normal} but also include CPU and thread utilzation
			{sync} = explicitly synchronize MPI tasks between sections
			{nosync} = do not synchronize MPI tasks when collecting timer info (default) :pre

			[Examples:]

			timers full sync
			timers loop :pre

			[Description:]

			Select to which level of detail LAMMPS is performing internal profiling.

			During regular runs LAMMPS will collect information about how much time is
			spent in different sections of the code and thus can provide valuable
			information for determining performance and load imbalance problems. This
			can be done at different levels of detail and accuracy. For more
			information about the timing output, please have a look at the "discussion
			of screen output"_Section_start.html#start_8.

			The {off} setting will turn all time measurements off. The {loop} setting
			will only measure the total time of run loop and not collect any detailed
			per section information. With the {normal} setting, timing information for
			individual sections of the code are collected and also information about
			load imbalances inside those sections presented. The {full} setting adds
			information about CPU utilization and thread utilization, when multi-threading
			is enabled.

			With the {sync} setting, all MPI tasks are synchronized at each timer call
			and thus allowing to study load imbalance more accuractly, but this usually
			has some performance impact. Using the {nosync} setting this can be turned
			off (which is the default).

			Multiple keywords can be provided and for keywords that are mutually
			exclusive, the last one in that group is taking effect.

			IMPORTANT NOTE: Using the {full} and {sync} options provides the most
			detailed and accurate timing information, but also can have a significant
			negative performance impact due to the overhead of the many required system
			calls. It is thus recommended to use these settings only when making tests
			to identify the performance. For calculations with few atoms or a very
			large number of performance, even using the {normal} setting can have
			a measurable performance impact. It is recommended in those cases to use
			the {loop} or {off} setting.

			[Restrictions:] none

			[Related commands:]
			"run post no"_run.html, "kspace_modify fftbench"_kspace_modify.html

			[Default:]

			timers normal nosync

lammps/doc/timers.txtd68c3769d0b4master

timers.txtView Options

lammps/doc/timers.txt
d68c3769d0b4master

timers.txt
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