Hp XC System 2.x Software Manuel d'utilisateur télécharger pdf (Page 51)

single compilation line, so it is common to talk about concu rrent compilations, though GNU

make is more general.

On non-cluster platforms or comm a nd nodes, matching concurrency to t he number of processors

oftenworkswell.Italsooftenworkswelltospecify a few more jobs than processors so that one

job can proceed while another is waiting for I/O. On an HP XC system, there is the potential to

use compute nodes to do co mp ilations, and there are a variety of ways to make this happen.

One way is to p ref ix the actual compilation line in the rule with an srun command. So, instead

of executing cc foo.c -o foo.o it would execute srun cc foo.c -o foo.o.

With concurrency, multiple command nodes would h ave multiple srun commands instead of

multiple cc comm ands. For projects that recursively run make on subdirectories, the recursive

make can be run on the compute nodes. For example:

$ cd subdir; srun $(MAKE)...

Further, if the recursive make is run remotely, it can be told to use concurrency on the remote

node. For example:

$ cd subdir; srun -n1 -N1 $(MAKE) -j4...

This can cause multiple makes to run concurrently, each building their targets concurrently.

The -N1 option is used to reserve the entire node, because it is intended to be used for multiple

compilations. The following examples illustrate these ideas. In GNU make,a$(VARIABLE)

that is unspecified is replaced with nothing. Therefore, not specifying PREFIX keeps the

original makefile’s behavior, but specifying PREFIX to appropriate srun command prefixes

will cause concurrency within the build.

For m ore information about GNU parallel make, refer to the make manpage. For additional

sources of GNU information, refer to the references provided in A bout This Docum ent.

In this section, t hree different w a ys to par a ll elize a make pro cedur e are il lustrated. The smg98

package is used to illustrate these three procedures. The smg98 package is available at the

following URL:

http://www.llnl.gov/asci/applications/SMG98README.html

These procedures take advantage of the GN U make -j switch, which specifies the number o f

jobs to run sim ultaneo usly. Refer to the make manpage for more information about this switch.

The following parallel make approaches are described:

• Section 3.9.1.1 — Go through the directories serially and have the make procedure within

each directory be parallel. (Modified makefile: Makefile_type1).

• Section 3.9.1.2 — Go through the directories in p arallel and have the make procedure

within each directory be s erial (Modified makefile: Makefile_type2).

• Section 3.9.1.3 — Go through the directories in p arallel and have the make procedure

within each directory be parallel (Modified makefile: Makefile_type3).

The original makefile is shown below:

#BHEADER***********************************************************

# See the file COPYRIGHT_and_DISCLAIMER for a complete copyright

# notice, contact person, and disclaimer.

# $Revision: 1.1 $

#EHEADER***********************************************************

SHELL = /bin/sh

Developing Applications 3-11

1 2 ... 46 47 48 49 50 51 52 53 54 55 56 ... 153 154

Commentaires sur ces manuels

Pas de commentaire

Hp XC System 2.x Software Manuel d'utilisateur Page 51

Commentaires sur ces manuels

Produits connexes et manuels pour Logiciel Hp XC System 2.x Software