How to Use MPI - Revision history

Paul-kapinos-e26d@rwth-aachen.de: /* Process Binding */

2020-06-12T07:13:39Z

Process Binding

Paul-kapinos-e26d@rwth-aachen.de: /* References */

2020-06-12T07:11:37Z

References

Paul-kapinos-e26d@rwth-aachen.de: /* Process Binding in Open MPI */

2020-06-12T07:00:28Z

Process Binding in Open MPI

Paul-kapinos-e26d@rwth-aachen.de: /* Intel MPI */

2020-05-05T10:51:43Z

Intel MPI

Paul-kapinos-e26d@rwth-aachen.de: /* References */

2020-05-05T10:45:11Z

References

Daniel-schurhoff-de23@rwth-aachen.de at 13:19, 3 September 2019

2019-09-03T13:19:44Z

Nina-loseke-fd7a@rwth-aachen.de at 13:34, 20 April 2018

2018-04-20T13:34:19Z

Christian-wassermann-e30b@rwth-aachen.de: /* Basics */

2018-04-16T14:53:53Z

Basics

Christian-wassermann-e30b@rwth-aachen.de: /* How to Compile MPI Code */

2018-04-16T07:42:03Z

How to Compile MPI Code

Christian-wassermann-e30b@rwth-aachen.de: /* Open MPI */

2018-04-13T14:38:05Z

Open MPI

@@ Line 118: / Line 118: @@
 Binding processes means telling your system how to place the processes onto the architecture. This can be done by adding command-line options when calling <code>mpiexec</code> and/or setting some environment variables (both verndor-specific), and may enhance (or kill) the performance of your application. In order to learn more about that, go here for [[Binding/Pinning#Options_for_Binding_in_Open_MPI|Open MPI]] and there for [[Binding/Pinning#Options_for_Binding_in_Intel_MPI|Intel MPI]].
-In most MPI vendors the Process Binding is '''on''' by default nowadays. All MPIs assume there is only ''one'' MPI job running on hardware at any time. If you start more than one MPI job (e.g. in context of non-exclusive batch job in a batch sheduler w/o binding management, or just interactive tests), all '''N''' jobs would belive they are only children, ''and would bind themselves to the very same cores'', resulting in ''1/N'' performance while remainig cores idling.
+In most MPI vendors the Process Binding is '''on''' by default nowadays. All MPIs assume there is only ''one'' MPI job running on hardware at any time. If you start more than one MPI job (e.g. in context of non-exclusive batch job in a batch sheduler w/o binding management, or just interactive tests), all '''N''' jobs would belive they are only children, ''and would bind themselves to the very same cores'', resulting in ''1/'''N''''' performance while remainig cores idling.
 == References ==

@@ Line 122: / Line 122: @@
 == References ==
-[https://software.intel.com/en-us/mpi-developer-reference-linux-compiler-command-options Intel MPI compiler options]
+[https://software.intel.com/content/www/us/en/develop/documentation/mpi-developer-reference-linux/top/command-reference/compilation-commands.html Intel MPI compiler options]
-[https://www.open-mpi.org/doc/v4.0/man1/mpiexec.1.php Manual page for Open MPI's mpiexec]
+Manual page for [https://www.open-mpi.org/doc/v4.0/man1/mpiexec.1.php Open MPI's] and [https://software.intel.com/content/www/us/en/develop/documentation/mpi-developer-reference-linux/top/command-reference/mpirun.html Intel MPI's] mpiexec/mpirun command.

@@ Line 114: / Line 114: @@
 |}
-=== Process Binding in Open MPI ===
+=== Process Binding ===
-Binding processes means telling your system how to place the processes onto the architecture. This can be done by adding command-line options when calling <code>mpiexec</code> and may enhance the performance of your application. In order to learn more about that, go [[Binding/Pinning#Options_for_Binding_in_Open_MPI|here]].
+Binding processes means telling your system how to place the processes onto the architecture. This can be done by adding command-line options when calling <code>mpiexec</code> and/or setting some environment variables (both verndor-specific), and may enhance (or kill) the performance of your application. In order to learn more about that, go here for [[Binding/Pinning#Options_for_Binding_in_Open_MPI|Open MPI]] and there for [[Binding/Pinning#Options_for_Binding_in_Intel_MPI|Intel MPI]].
 == References ==

← Older revision		Revision as of 10:51, 5 May 2020
Line 39:		Line 39:

	=== Intel MPI ===		=== Intel MPI ===
		+	The Intel MPI is shipped with ''two'' sets of compiler wrappers (for GCC and for Intel compilers); it is rather important to use the right ones. Especially when using any software building tolls like [[Cmake\|CMake]], double-check carefully about the right compiler wrappers being actually used, otherwise you will call the wrong compilers internally.

	Use the following command to specify the program you would like to compile (replace <code><src_file></code> with a path to your code, e. g. <code>./myprog.c</code>).		Use the following command to specify the program you would like to compile (replace <code><src_file></code> with a path to your code, e. g. <code>./myprog.c</code>).

← Older revision		Revision as of 10:45, 5 May 2020
Line 121:		Line 121:
	[https://software.intel.com/en-us/mpi-developer-reference-linux-compiler-command-options Intel MPI compiler options]		[https://software.intel.com/en-us/mpi-developer-reference-linux-compiler-command-options Intel MPI compiler options]

−	[https://www.open-mpi.org/doc/v2.0/man1/mpiexec.1.php Manual page for Open MPI's mpiexec]	+	[https://www.open-mpi.org/doc/v4.0/man1/mpiexec.1.php Manual page for Open MPI's mpiexec]

← Older revision		Revision as of 13:19, 3 September 2019
Line 1:		Line 1:
		+	[[Category:HPC-User]]
	== Basics ==		== Basics ==

← Older revision		Revision as of 13:34, 20 April 2018
Line 2:		Line 2:

	This page will give you a general overview of how to compile and execute a program that has been [[Parallel_Programming\|parallelized]] with [[MPI]]. Many of the options listed below are the same for both Open MPI and Intel MPI, however, be careful and look up if they indeed behave the same way.		This page will give you a general overview of how to compile and execute a program that has been [[Parallel_Programming\|parallelized]] with [[MPI]]. Many of the options listed below are the same for both Open MPI and Intel MPI, however, be careful and look up if they indeed behave the same way.
		+
		+
		+	__TOC__
		+

	== How to Compile MPI Code ==		== How to Compile MPI Code ==

@@ Line 1: / Line 1: @@
 == Basics ==
-This page will give you a general overview of how to compile and execute a program that has been [[Parallel_Programming|parallelized]] with [[MPI]]. Many of the options listed below are the same for both Open MPI and Intel MPI, however, be careful if they do differentiate.
+This page will give you a general overview of how to compile and execute a program that has been [[Parallel_Programming|parallelized]] with [[MPI]]. Many of the options listed below are the same for both Open MPI and Intel MPI, however, be careful and look up if they indeed behave the same way.
 == How to Compile MPI Code ==

@@ Line 31: / Line 31: @@
 |}
-For RWTH cluster users:
+Instead of typing the compiler wrapper <code>mpicc</code>, <code>mpicxx</code> or <code>mpifort</code> explicitly, on most systems (e.g. the RWTH Compute Cluster) there are environment variables defined, which you can use to call the MPI compiler in a more general manner. Simple use <code>$MPICC</code>, <code>$MPICXX</code> or <code>$MPIFC</code> for the compiler you want to use and let the module system handle the dirty details of using the appropriate command.
 === Intel MPI ===
@@ Line 56: / Line 55: @@
 |}
-For RWTH cluster users:
+Instead of typing the compiler wrapper <code>mpicc</code>, <code>mpicxx</code> or <code>mpifort</code> explicitly, on most systems (e.g. the RWTH Compute Cluster) there are environment variables defined, which you can use to call the MPI compiler in a more general manner. Simple use <code>$MPICC</code>, <code>$MPICXX</code> or <code>$MPIFC</code> for the compiler you want to use and let the module system handle the dirty details of using the appropriate command.
 == How to Run an MPI Executable ==

@@ Line 80: / Line 80: @@
 |-
 | -wdir <directory> || change to directory specified before executing the program
 |-
 | -path <path> || look for executables in the directory specified