[dpdk-users] False conflicts over .rte_config lock file

[dpdk-users] False conflicts over .rte_config lock file

[John Ousterhout]

I recently upgraded to the DPDK git head, and am now getting messages of
the following form when I run RAMCloud using DPDK:

EAL: Error - exiting with code: 1
  Cause: Cannot create lock on '/home/ouster/.rte_config'. Is another
primary process running?

This is a false conflict that is coming about because several different
DPDK applications are starting up on several different nodes (only one per
node), but they are all running in the same shared NFS home directory. It
appears that DPDK is choosing the same lock file for all of the nodes,
which fools it into thinking that multiple DPDK applications are running on
the same node.

Is there a way to get rid of this conflict? I have seen the --file-prefix
in the documentation, but generating a unique prefix for each application
is nontrivial. I suppose I could just generate a large random number and
assume there will be no conflicts, but I'm wondering if there is a cleaner
mechanism supported by DPDK. I would guess that running multiple DPDK apps
on different nodes in a shared directory might be fairly common?

-John-