Packet assembly module for multi-core, multi-thread network processors

A method of assembling output packets of a network processor implemented as a system-on-chip, the network processor processing received packets with a plurality of processing modules into one or more processed-packet portions, the network processor coupled to an external memory, the method comprising:

• receiving, by a shared on-chip system memory of the network processor, one or more processed-packet portions corresponding to one or more packet assemblies, each of the packet assemblies having one or more associated tasks, the packet assembly processor comprising an input queue configured to receive the one or more associated tasks for the packet assemblies;
• constructing, by a packet assembly processor, an output packet for each packet assembly from the one or more processed-packet portions in accordance with instructions from the one or more tasks associated with the packet assembly;
• coordinating, by the packet assembly processor, storage of the one or more processed-packet portions for each output packet that is read from the system memory based on the instructions from the one or more tasks associated with the corresponding packet assembly;
• entering a drop mode upon detecting that a depth of the input queue has reached a threshold, wherein the drop mode comprises:
• removing an oldest task from the input queue;
• setting a drop indication in a state data entry corresponding to the packet assembly associated with the removed task;
• dropping one or more subsequent tasks from the input queue, without processing the tasks, until the input queue depth is below the threshold;
• setting a drop indication in a state data entry corresponding to the packet assembly associated with the one or more dropped tasks;
• removing the packet assembly having the drop indication set from the system memory without constructing an output packet, thereby avoiding transmitting corrupt output packets;
• sending an indicator to a destination device that a corresponding packet assembly was dropped;
• and
• when the input queue depth is below the threshold:
• exiting the drop mode and processing an oldest task in the input queue.

A non-transitory machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method of assembling output packets of a network processor implemented as a system-on-chip, the network processor processing received packets with a plurality of processing modules into one or more processed-packet portions, the network processor coupled to an external memory, the method comprising:

• receiving, by a shared on-chip system memory of the network processor, one or more processed-packet portions corresponding to one or more packet assemblies, each of the packet assemblies having one or more associated tasks, the packet assembly processor comprising an input queue configured to receive the one or more associated tasks for the packet assemblies;
• constructing, by a packet assembly processor, an output packet for each packet assembly from the one or more processed-packet portions in accordance with instructions from the one or more tasks associated with the packet assembly;
• coordinating, by the packet assembly processor, storage of the one or more processed-packet portions for each output packet that is read from the system memory based on the instructions from the one or more tasks associated with the corresponding packet assembly;
• entering a drop mode upon detecting that a depth of the input queue has reached a threshold, wherein the drop mode comprises:
• removing an oldest task from the input queue;
• setting a drop indication in a state data entry corresponding to the packet assembly associated with the removed task;
• dropping one or more subsequent tasks from the input queue, without processing the tasks, until the input queue depth is below the threshold;
• setting a drop indication in a state data entry corresponding to the packet assembly associated with the one or more dropped tasks;
• removing the packet assembly having the drop indication set from the system memory without constructing an output packet, thereby avoiding transmitting corrupt output packets;
• sending an indicator to a destination device that a corresponding packet assembly was dropped;
• and
• when the input queue depth is below the threshold:
• exiting the drop mode and processing an oldest task in the input queue.