Automatic Hardware Trigger of APM
The Causes
When both the local and remote QP or EEC are in the Arm state, they are primed for a path migration. As indicated earlier, a path migration can be triggered either when:
Local software commands (via the Modify QP or Modify EEC verb) the local QP or EEC to transition from the Arm state to the Migrated state or
The QP or EEC experiences Retry Count Exhaustion.
An automatic path migration is triggered on Retry Count exhaustion and can occur due to any of the following circumstances:
Repetitive PSN Sequence Error Naks. If either QP's or EEC's Send Logic receives a PSN Sequence Error Nak, it decrements its Retry Count. If the count is not exhausted, it retries the transmission of that request packet. If ...
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