Westmere, Sandybridge, Ivybridge, Haswell and Broadwell Cores

Jobs running on Intel hardware can run on Westmere, Sandybridge, Ivybridge, Haswell or Broadwell CPUs (Broadwell being the newest type). You can choose to restrict your job to a specific architecture or allow the system to choose any of them:

• Using a specific architecture is needed when timing code, doing several runs of the code with increasing numbers of cores – the same architecture should be used for each run.
• Using a specific architecture will however mean the scheduler has a smaller number of nodes on which your job can run.
• By not specifying an architecture (leaving it to the system to choose) the scheduler has many more nodes on which it can look for free cores to run your job.

In general, if your job doesn’t care which architecture it runs on, do not restrict it to a specific architecture – your job may spend less time in the queue.

See below for other advantages of running on Sandybridge, Ivybridge, Haswell or Broadwell CPUs.

A number of nodes have Westmere, Sandybridge, Ivybridge, Haswell or Broadwell cores.

• Westmere provides 12 cores per node
• Sandybridge provides 12 cores per node
• Ivybridge provides 16 cores per node
• Haswell provides 24 cores per node
• Broadwell provides 24 cores per node

Your job may run faster on these nodes depending on whether it has been compiled with the Intel Compiler and AVX (or AVX2) flags to take advantage of the architecture. Please see the CSF Intel Compiler documentation for further info.

• The Sandybridge/Ivybridge nodes are not InfiniBand connected. Hence do not request Sandybridge/Ivybridge if using the orte-24-ib.pe parallel environment (such jobs will land automatically on the Haswell nodes without additional flags).
• Wait times for the Sandybridge/Ivybridge cores are no shorter than the main 7 day pool because these nodes are currently part of the main 7 day pool of Intel nodes.
• The short resources dot not contain any Sandybridge, Ivybridge, Haswell hardware so do not use these architecture flags when running using -l short.

If you do not want to specify an architecture (instead letting the system choose) simply ignore the flags below.

Note also that you must still specify how many cores you wish to use if submitting parallel jobs. The architecture flags can be used with both serial and parallel jobs. For example, the following will request 6 cores on a sandybridge node:

#$ -pe smp.pe 6             # A parallel job. Remove this line for serial jobs.
#$ -l sandybridge           # Ensure the job always lands on a Sandybridge node.

Without the -pe flag you will be given one core for a serial job.

To request Westmere cores (max 12 cores) for your jobs add the following to your job script:

#$ -l westmere

To request Sandybridge cores (max 12 cores) for your jobs add the following to your job script:

#$ -l sandybridge   

To request Ivybridge cores (max 16 cores, not valid for serial jobs) for your jobs add the following in your job script:

#$ -l ivybridge

-24.01.2019 No longer available due to upgrade work.

To request Haswell cores (max 24 cores, not valid for serial jobs) for your jobs add the following in your job script:

#$ -l haswell       

To request Broadwell cores (max 24 cores, not valid for serial jobs) for your jobs add the following in your job script:

#$ -l broadwell

-24.01.2019 No longer available due to upgrade work.