OR
crawl route-byte-sequence
crawl is a self-ping utility for myrinet on Cplant. It is run on a service or compute node to test each hop in a myrinet route from the local node to a specified desination node. It takes as argument the node id of the destination machine or a space-separated list of route bytes, each of the form 0xST with S and T hex digits.
crawl is a perl script that translates its local node id to a machine name by calling pnid2hname. In the case of a specified destination node it uses this name along with the specified destination node id to parse a route sequence out of the directory of Cplant route files. Then it invokes the troute(1) utility. troute in turn makes ioctl() calls to the portals and rtscts devices.
crawl performs a self-ping test for each byte of the route on the path to the destination machine; each time a ping packet enters a new switch it immediately goes back out that port and retraces the route back to the node of origin.
crawl must be run as the superuser.