International Business Machines Corporation

Compagnie Ibm France

William John Goetzinger

Glen Howard Handlogten

James Francis Mikos

David Alan Norgaard

Fabrice Jean Verplanken

Jean Louis Calvignac

Marco C Heddes

Joseph Franklin Logan

Kent Harold Haselhorst

Lonny Lambrecht

Daniel James Sucher

Merwin Herscher Alferness

Joshua W Rensch

In a first aspect, a first method is provided for self-adjusting allocation of memory bandwidth in a network processor system. The first method includes the steps of (1) determining an amount of memory bandwidth of a network processor used by each of a plurality of data types; and (2) dynamically adjusting the amount of memory bandwidth allocated to at least one of the plurality of data types based on the determination. Numerous other aspects are provided.

Methods and apparatus for allocating bandwidth for a network processor

A data communication apparatus includes a plurality of output ports and a scheduler for assigning priorities for outbound data frames. The scheduler includes one or more scheduling queues. Each scheduling queue indicates an order in which data flows are to be serviced. At least one scheduling queue has a respective plurality of output ports assigned to the scheduling queue. That is, the scheduling queue is shared by two or more output ports.

Weighted fair queue serving plural output ports

In a first aspect, a network processor services a plurality of flows including a first flow and a discard flow. The first flow includes a first flow queue and the discard flow includes a discard queue that lists frames to be discarded. An indication is made that the first flow is to be disabled. In response to the indication, all frames included in the first flow queue are transferred to the discard queue. Because the first flow queue is now empty, reconfiguration of the first flow may proceed immediately.

Network processor having fast flow queue disable process

A scheduler for a network processor includes one or more scheduling queues. Each scheduling queue defines a respective sequence in which flows are to be serviced. A respective empty indicator is associated with each scheduling queue to indicate whether the respective scheduling queue is empty. By referring to the empty indicators, it is possible to avoid wasting operating cycles of the scheduler on searching scheduling queues that are empty.

Empty indicators for weighted fair queues

A scheduler for a network processor includes a scheduling queue in which weighted fair queuing is applied. The scheduling queue has a range R. Flows are attached to the scheduling queue at a distance D from a current pointer for the scheduling queue. The distance D is calculated for each flow according to the formula D=((WF&#xd7;FS)/SF), where WF is a weighting factor applicable to a respective flow; FS is a frame size attributable to the respective flow; and SF is a scaling factor. The scaling factor SF is adjusted depending on a comparison of the distance D to the range R.

Weighted fair queue having adjustable scaling factor

In a first aspect, a network processor includes a scheduler in which a scheduling queue is maintained. A last frame is dispatched from a flow queue maintained in the network processor, thereby emptying the flow queue. Data indicative of the size of the dispatched last frame is stored in association with the scheduler. A new frame corresponding to the emptied flow queue is received, and the flow corresponding to the emptied flow queue is attached to the scheduling queue. The flow is attached to the scheduling queue at a distance D from a current pointer for the scheduling queue. The distance D is determined based at least in part on the stored data indicative of the size of the dispatched last frame.

Method and apparatus for improving the fairness of new attaches to a weighted fair queue in a quality of service (QoS) scheduler

A scheduler for a network processor includes a scheduling queue in which weighted fair queuing is applied to define a sequence in which flows are to be serviced. The scheduling queue includes at least a first subqueue and a second subqueue. The first subqueue has a first range and a first resolution, and the second subqueue has an extended range that is greater than the first range and a lower resolution that is less than the first resolution. Flows that are to be enqueued within the range of highest precision to the current pointer of the scheduling queue are attached to the first subqueue. Flows that are to be enqueued outside the range of highest precision from the current pointer of the scheduling queue are attached to the second subqueue. Numerous other aspects are provided.

Weighted fair queue having extended effective range

A scheduler, scheduling method, and computer program product are provided for implementing Quality-of-Service (QoS) scheduling of a plurality of flows with aging time stamps. Subsets of time stamp data stored in a time stamp aging memory array are sequentially accessed. Each time stamp data subset contains time stamp data for a subplurality of flows. Guaranteed aging processing steps are performed for each flow utilizing the time stamp data subsets to identify and mark invalid calendar next time values. When a new frame arrival for an empty flow is identified, flow queue control block (FQCB) time stamp data and the flow time stamp data in the time stamp aging memory array are accessed. Based on the calendar to which the new frame is directed or the target calendar for the new frame, the target calendar next time valid bit of the time stamp aging memory array data is checked. When the target calendar next time valid bit is on, a target calendar next time value from the flow queue control block (FQCB) time stamp data is compared with a current time. When the target calendar next time is less than the current time, the target calendar next time valid bit is turned off to mark the target calendar next time as invalid. The guaranteed aging processing steps for each flow in the time stamp data subset includes checking a selection indicator of the time stamp aging memory array data for the flow to identify a calendar. Responsive to the selection indicator value, a calendar valid bit is checked. When the calendar valid bit is on, a calendar next time is compared with a current time. When the calendar next time is less than the current time, the calendar valid bit is turned off to mark the calendar next time as invalid. Invalid time stamp values are identified for all scheduler calendars.

QoS scheduler and method for implementing quality of service with aging time stamps

A QoS scheduler, scheduling method, and computer program product are provided for implementing Quality-of-Service (QoS) scheduling with a cached status array. A plurality of calendars are provided for scheduling the flows. An active flow indicator is stored for each calendar entry in a calendar status array (CSA). A cache copy subset of the active flow indicators from the calendar status array (CSA) is stored in a cache. The calendar status array (CSA) is updated based upon a predefined calendar range and resolution. The cache copy subset of the active flow indicators from the calendar status array (CSA) is used to determine a given calendar for servicing. The subset of the active flow indicators from the calendar status array (CSA) is used to increment a current pointer (CP) by an identified number of positions up to a current time (CT) value, where the identified number of positions is equal to a variable number of inactive flow indicators up to the current time (CT) value and the identified number of positions has a maximum value equal to a number of entries in the cache.

QoS scheduler and method for implementing quality of service with cached status array

A Network Processor (NP) is formed from a plurality of operatively coupled chips. The NP includes a Network Processor Complex (NPC) Chip coupled to a Data Flow Chip and Data Store Memory coupled to the Data Flow Chip. An optional Scheduler Chip is coupled to the Data Flow Chip. The named components are replicated to create a symmetric ingress and egress structure.

High speed network processor

A QoS scheduler, scheduling method, and computer program product are provided for implementing Quality-of-Service (QoS) scheduling with detecting and anticipating the end of a chain of flows. A first indicator is provided for indicating a number of flows being chained to a physical entry. A second indicator is provided for indicating when the first indicator has saturated. The second indicator is set active for a flow whose chaining causes the first indicator to saturate. During de-chaining of the flows from the physical entry, the second indicator is used to determine when the first indicator becomes accurate to begin decrementing the first indicator. The first indicator is decremented for detecting the end of the chain of flows. Responsive to the first indicator being not saturated, the first indicator is used for anticipating the end of a chain of flows. The first indicator and the second indicator include a predefined number of bits or n-bits. The first indicator includes n&#x2212;1 bits stored in a physical entry and the second indicator includes 1-bit stored in a chained link list.

QoS scheduler and method for implementing quality of service anticipating the end of a chain of flows

A scheduler and scheduling method implement peak service distance using a next peak service time violated (NPTV) indication. A flow scheduled on a best effort or weighted fair queue (WFQ) is identified for servicing and a frame is dispatching from the identified flow. A next PSD time (NPT) being violated is checked for the flow. Responsive to identifying the next PSD time (NPT) being violated for the identified flow, a NPTV indicator is set. Alternatively, responsive to identifying the next PSD time (NPT) not being violated for the identified flow, the NPTV indicator is reset. A next PSD time (NPT) value is calculated for the flow. Checking for more frames to be dispatched from the flow is performed. Responsive to identifying no more frames to be dispatched from the flow, the NPTV indicator is utilized to identify a calendar for attaching the flow upon a new frame arrival for the flow. If the NPTV indicator is not set when the flow goes empty, upon a new frame arrival for the flow, the flow is attached to a weighted fair queue (WFQ) ring using a queue distance calculation. If the NPTV indicator is set when the flow goes empty, upon a new frame arrival for the flow, then it is determined if the next PSD time (NPT) value for the flow has been passed. If the next PSD time (NPT) value has been passed, then the flow is attached to the weighted fair queue (WFQ) ring using the queue distance calculation. If the next PSD time (NPT) value has not been passed, then the flow is attached to a peak bandwidth service (PBS) calendar using the next PSD time (NPT) value.

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Rochester, MN, United States of America

William John Goetzinger