
34
Process 1 on hostB
Process 0 on hostA
pi is approximately 3.1416009869231241, Error is 0.0000083333333309
wall clock time = 0.000263
4.6 Removing the Ammasso MPI Installation
Use the
mpich_uninstall
command to remove the AMSO_MPICH installation. This
command will not remove
machines.*
files in the
<install_dir>/mpich-
1.2.5/share
directory. These files are left on the system for use in the future if needed.
# . /etc/ammasso.conf
# $INSTALL_DIR/mpich-1.2.5/mpich_uninstall
Uninstall mpich found at /usr/opt/ammasso/mpich-1.2.5 (y or n)? [no] y
The following files were saved:
/usr/opt/ammasso/mpich-1.2.5/share/machines.sample
/usr/opt/ammasso/mpich-1.2.5/share/machines.LINUX
#
If a 32b library exists on a 64b system, remove that installation as well:
# . /etc/ammasso.conf
# $INSTALL_DIR/mpich-1.2.5-32/mpich_uninstall
Uninstall mpich found at /usr/opt/ammasso/mpich-1.2.5-32 (y or n)? [no] y
Mpich in /usr/opt/ammasso/mpich-1.2.5-32 has been removed.
The following files were saved:
/usr/opt/ammasso/mpich-1.2.5-32/share/machines.sample
/usr/opt/ammasso/mpich-1.2.5-32/share/machines.LINUX
#
4.7 Ammasso MPI Tunable Parameters
The following parameters can be used to tune the maximum amount of memory that will be
consumed by the AMSO_MPICH RDMA driver. Memory consumed by the driver is locked
down, or pinned, and not available for application or even operating system use, so at times it
can be necessary to adjust these parameters to limit how much memory the driver will lock
down.
NOTE:
This also affects the performance of the driver, and overly reducing these limits
can cause extremely poor performance. Conversely, setting these too high can cause
consumption of all memory on the system. Caution should be used when adjusting these
parameters.
For the purpose of this discussion, four variables are defined; Node Count, (NC), Local
Process count (LP), Number of Processes (NP), and the Remote Process count (RP).
NC
is defined as the number of nodes used in an MPI run.
LP
is defined as the number of
local
processes on each compute node. We assume, in this
discussion, that each compute node runs the same number of MPI processes.