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Alessandro Rubini authored
This adds a tool to check the latency in the network. It is selected at build time (config) time. If you select CONFIG_LATENCY_PROBE you are then asked for a CONFIG_LATENCY_ETHTYPE. The sender node sends three frames, as broadcast in that ethertype within the current vlan (or no vlan). The first frame is at priority 7, the second at priority 6, and the third includes the egress timestamps for the former ones. Each group has a sequence number and group identifier. If the tool is built in wrc.bin, every node acts as a receiver. To enable a sender issuing the set of frames every 5 seconds, use "ltest 5". To disable use "ltest 0". The receiver prints the measured latency, and warns if it receives frames that are not in the proper order, using the sequence and frame type fields. This is a successful run crossing two wr switches: latency prio7: 5142.775 latency prio6: 4998.775 latency prio7: 4822.773 latency prio6: 5142.773 latency prio7: 5142.771 latency prio6: 5286.771 Later on, we'll make the thing less verbose, and we'll have threshold to signal a problem if the network went slow. Currently we just print all collected data. Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
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