The resources available for ''LIP'' users are a mix of servers from different generations and brands, as seen on the following table. The '''feature''' name tag may be used on the '''--constraint ''' ''sbatch'' option to request a specific '''CPU''' type.

||<#ffffcc>'''Model''' ||<#ffffcc>'''CPU Desciption''' ||<#ffffcc>'''Features''' ||
||HP BL460c G6 ||Intel(R) Xeon(R) CPU X5550 @ 2.67GHz ||intel nehalem ||
||HP DL160 G5 ||Intel(R) Xeon(R) CPU E5472 @ 3.00GHz ||intel core2 ||
||HP DL160 G6 ||Intel(R) Xeon(R) CPU E5540 @ 2.53GHz ||intel nehalem ||
||IBM LS22 ||Quad-Core AMD Opteron(tm) Processor 2356 ||amd opteron ||
||IBM HS21 ||Intel(R) Xeon(R) CPU L5420 @ 2.50GHz ||intel core2 ||


For example, suppose we want to target only '''Intel''' processors, then we would include the '''--constraint=intel''' option on our '''[[https://wiki-lip.lip.pt/Computing/LIP_Lisbon_Farm/6_SLURM/6.2_Job_Submission_from_a_non_Shared_Directory|root example]]''':

{{{
[uname@pauli01 mdir]$ cat MyMacro.sh
#!/bin/bash
# --------------------------------------------------------------------- #

# Select partition, or queue. The LIP users should use "lipq" partition
#SBATCH -p lipq

# Transfer input files to the execution machine
# INPUT = MyMacro.c

# Transfer output files back to submission machine
# OUTPUT= graph_with_law.pdf

# Request Intel processor
#SBATCH --constraint=intel

# --------------------------------------------------------------------- #
# Load environment
module load root/6.18.04

# Execute macro
root -b -q MyMacro.c

[uname@pauli01 mdir]$ sbatch MyMacro.sh
}}}

For example the '''Gate''' application may crash if executed on an old '''AMD Opteron''' '''CPU''', in this case we would provide '''--constraint=intel''' option to target only '''Intel CPUs'''. 

Another example, suppose we would like to target the best performant '''CPU''' '''nehalem''', then we can simply request '''--constraint=nehalem'''.


Nodes have '''features''' assigned that stand for the supported '''CPU''' types like the ones found on the table above. For the time being only '''CPU''' type features are available but other caracteristics will be available in the near future. The request will be satisfied only by nodes having the features matching the job constraints.

Multiple constraints may be specified with '''AND''', '''OR''' or '''comma''', the '''OR''' operator is equivalent to '''comma'''. Check the sbatch manual page for more details: '''man sbatch'''.
If no constraints are specified then the job will be eligeble to run on all '''CPUs''' or servers.