| 摘要 |
A system and method for synchronizing a set of nodes connected to a central switch in a multi-node data processing system, such as a NUMA data processing system, are disclosed. Initially, time base register values are retrieved from each of the set of nodes. A common time base register value is then determined based upon the time base register values received from the nodes. The common time base register value that is determined is then broadcast to each of the nodes. Prior to reading the time base register values, packet traffic among the set of nodes may be halted by broadcasting a halt traffic packet to each of the nodes. In this embodiment, normal packet traffic may be resumed after synchronization by broadcasting a resume traffic packet to each of the nodes. The time base register values may be read by issuing a special purpose interrupt from a node adapter to one of the node processors in response to the adapter receiving a read time base packet from the switch. The common time base register value may be determined by selecting the maximum of the time base register values read from each of the set of nodes and adjusting the maximum time base register value by an adjustment factor, such as the time required for a packet to travel from the central switch to a node processor plus the time required for a packet to travel from a node processor to the central switch. The synchronization process may be repeated periodically such as by initiating a synchronization each time a decrementing register of the central switch reaches zero.
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