Idphix

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This page describes the first steps to play with the Xeon Phi installed in the Digitalis platform in idphix.

Contents

Overview

A Xeon Phi 5110P is installed in the idphix machine

The setup is the following:

We use an internal network on the host (idphix) for the Xeon Phi: 192.168.1.0/24.

This gives the following scheme:

                          =======================================
                        | -------------             -----------  |
                        ||    host     |           |  Xeon Phi | |
                        ||   idphix    |           |idphix-mic0| |
Grid5000 network <---> eth0           mic0 <----> mic0         | |
                    172.16.21.6 192.168.1.254  192.168.1.1     | |
                        ||             |           |           | |
                        | -------------             -----------  |
                          =======================================


How to experiment ?

For now (2013-09-13) the operating system is a Centos 6 (OS officially supported by Intel for the Xeon Phi).

Use the machine as follows:

Connect to digitalis/grid5000

workstation$ ssh digitalis.grenoble.g5k

In case of any issue (network issue, connection hanging...) please read more info here or ask on the Digitalis mailing list.

Reserve the machine/run a job

digitalis$ oarsub -p "machine='idphix'" -l walltime=2 -I

Setup your access to the Xeon Phi

(This might not be relevant if your are using some level of abstraction (COI, ...)

Make sure you created your G5K ssh keys (keys without passephrase protection, dedicated to G5K and stored in your NFS home directory)

Run:

idphix$ sudo /usr/local/bin/mic-setup-my-user

If you get the error:

Error: Cannot get your SSH keys, please run 'chmod 755 ~/.ssh && chmod 644 ~/.ssh/{authorized_keys,id_*.pub}'

Please run:

idphix$ chmod 755 ~/.ssh && chmod 644 ~/.ssh/{authorized_keys,id_*.pub}

Output should be:

idphix$ sudo /usr/local/bin/mic-setup-my-user 
*** Configure user pneyron:users (10106:8000) on mic0
*** Copy user files to mic0
id_rsa.pub                                    100%  420     0.4KB/s   00:00    
authorized_keys                               100%  916     0.9KB/s   00:00    
.profile                                      100%   62     0.1KB/s   00:00    
*** Force creation of pneyron:users on mic0 and fix file ownership and permission
Done

You shoud now be able to ssh to the coprocessor:

idphix$ ssh mic0
idphix-mic0$ uname -a
Linux idphix-mic0.grenoble.grid5000.fr 2.6.38.8-g5f2543d #2 SMP Tue Apr 30 14:05:06 PDT 2013 k1om k1om k1om GNU/Linux

Intel compiler, compilation for the MIC

Intel compiler (icc & co) is installed in /opt/intel /applis/digitalis/intel.

It is configured to use Inria's license server (FlexLM).

This licence server provides 2 tokens which are shared among all Inria's users. Only 2 compilations can be performed at a time.

If icc complains about the license (error message talking about FlexLM), please report the issue to digitalis@lists.grid5000.fr

Rebooting the MIC

If needed, you can reboot the MIC from within a exclusive job (doing so in shared job session would risk annoying other users).

oarsub -t exclusive -p "machine='idphix'" ....

Then, you will be able to run

sudo /usr/local/bin/mic-reboot

(no password should be requested).

Rebooting the MIC takes some time. You can look at the output of dmesg or miccrtl -s meanwhile.

Data on the mic: no persistence

Please mind the fact that data pushed to the mic are not persistent. Your home directory on idphix-mic0 could be emptied for various reasons.

References

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