The primary computing platform will be an instructional cluster (the
Totient cluster) with fifteen Xeon Phi 5110P
boards hosted in eight 12-core compute nodes consisting of
Intel Xeon E5-2620 v3 processors and 32 GB RAM per node.
totient-02 has one Phi board; the other compute nodes have two.
The head node is not as powerful as the compute nodes; please
refrain from using it to run computationally intensive jobs.
Unless otherwise stated, homework and projects should be tested and
timed on these machines.
The cluster runs RedHat Enterprise Linux 6.7 (Santiago). The system base compilers are a bit old, but we plan to install the Developer Toolset with more recent versions of the compiler as well as some utilities.
Intel generously donated the Xeon Phi boards and funded the purchase of the host machines, which were provided with deep matching discounts by Dell.
Accounts and login
In order to obtain access to the cluster, you will need to be enrolled in the class. If you want access as an informal auditor, you will need to contact me (David Bindel) regarding access; please make sure you send your netid in any such email. The Cornell information systems don’t all talk to each other, so please also drop me a note if you are adding or dropping the course after the first week or so, so that we can keep the account information up to date.
Basic login information
The cluster head node is
It is accessible via SSH. You will need to be on the campus network
(or connected via the
campus VPN) in order to
access this machine. The cluster login information is synchronized
with the campus Active Directory, so your login name is your Cornell
netid and your password is the associated password.
I recommend setting up SSH key-based authentication so that you don’t have to type your password every time you log in. From your private machine (e.g. a laptop computer), you can generate an SSH key pair; see, for example this tutorial. How to generate an SSH key and register it with an agent varies a bit depending on your operating system and SSH client; my recommendation is
If you are on Mac OS X, the native SSH client can use the system keychain directly. To add your private key, simply use the command
ssh-add -K /path/of/private/key
If you are on a Linux variant, or if you are using Cygwin under Windows, I recommend using the keychain program. If you are running GNOME, you likely have GNOME Keyring already installed on your system and do not need keychain. If are you running KDE, you likely have KWallet, a similar program. If you do not have these, you can still use keychain.
Under Windows, PuTTY seems to be the most common SSH client (unless you are using the SSH client under Cygwin). One set of directions for setting up passwordless ssh is here. I have little personal experience with this, so feel free to put in a better link!
Once you have generated an SSH key, copy the public part of the key to
.ssh/authorized_keys and change the permission by typing
chmod 600 ~/.ssh/authorized_keys at the command prompt on the head node.
Then you should be set to go.
Public keys, agent forwarding, and GitHub
You can use SSH public keys for write access to your GitHub repository (and likewise with BitBucket, GitLab, and most other hosted solutions). GitHub has a useful five-step walkthrough for setting this up.
If you want to use a single SSH key on your laptop to also access
your repositories from the class cluster, you may want to
log in with
In my case, I have the following lines in my laptop
to simplify logging into the cluster with agent forwarding:
Host totient Hostname en-cs-totient-01.coecis.cornell.edu User dsb253 ForwardAgent yes
Submitting batch jobs
For simple compiling, editing, and testing, you can work on the
Totient head node. For timing runs, you will want to submit jobs to
the batch queue system. Batch jobs on the Totient cluster are managed by the
resource manager. To run a batch job, you will need to create a PBS
script; for example, the
on a single machine, sending an email to my address if anything went
#!/bin/sh #PBS -N hostname #PBS -j oe #PBS -M email@example.com hostname
To submit this, I would run
qsub hostname.pbs; and I can see the status
(queued, running, exiting, completed) by running
completion, I would have a file called
hostname.o35 (or similar)
with the output of the script.
Batch scripts must be script files, but they don’t have to use the standard Bourne or BASH shells. If you prefer, you can use csh, zsh, or Python! Just change the executable mentioned in the first line. This can be useful when doing things that are more complex than running a single executable, such as running parameter studies.
High-performance computing installations often use environment modules to manage the (sometimes conflicting) software requirements for different applications and environments. For example, different modules may be available for different implementations of MPI, different compilers, or different versions of major libraries.
Using environment modules
The basic module commands are:
module avail: list available modules
module list: list loaded modules
module load foo: load module
module unload foo: unload module
To load a standard set of modules for the class, do
module load cs5220
This will load the
General system tools
The default tools on the system are rather old. The
utils packages are there to get newer versions of the most critical
tools (e.g. compiler support).
cs5220: Load a standard set of modules for the class
binutils, and various other utilities
devtoolset: RedHat devtoolset-3 developer utilities
The system Python installation is Python 2.6. We have vanilla Python 2.7 and 3.4.3 installs, but for anything serious, I recommend using the Anaconda Python distribution (which comes with Python 2.7 and Python 3.4 with a full NumPy/SciPy stack, Matplotlib, and many other utilities).
anaconda: Anaconda Scientific Python distribution
python/2.7: Generic Python build (version 2.7)
python/3.4.3: Generic Python build (version 3.4.3)
Compilers and such
In addition to the system GCC (4.4.7) and the
(4.9.2), we have the Intel compilers and Clang/Clang++ available.
We also have GCC 5.2.0, though I didn’t build that much for it.
psxe/2015: Intel Parallel Studio XE 2015 (Intel compilers, VTune, etc)
llvm/3.7.0: LLVM 3.7 and ISPC
gcc/5.2.0: GCC 5.2.0
upc/2.20.2: Berkeley Unified Parallel C
Boost is a standard set of tools for C++. Armadillo and Eigen are linear algebra libraries in C++; if you have no preference between the two, I recommend Armadillo.
We’re going to see BLAS and LAPACK early in the semester, and also FFTW and perhaps SuiteSparse. We likely won’t say anything in particular about GSL, but it’s there if you want it.
fftw: Fastest Fourier Transform in the West
suitesparse: SuiteSparse sparse linear solvers
gsl: GNU Scientific Library
HDF5 is one of the major standards for storing large volumes of scientific data. NetCDF plays in the same space as HDF5, and MatI/O is a set of convenience wrappers that’s kind of nice if you want to read and write MATLAB files.
hdf5: HDF5: Heirarchical Data Format library
netcdf: NetCDF: Network Common Data Format library
matio: Matrix I/O library
We have multiple OpenMPI implementations installed, as well as Intel MPI. If you’re going to use OpenMPI, I recommend one of the OpenMPI 1.10.0 builds.